CN207007336U - Raman spectrum test system - Google Patents

Abstract

A tunable Raman spectrum testing system, including a broad-spectrum monochromatization module, an optical path coupling and output module, and a signal detection module, wherein: the broad-spectrum monochromatization module includes: a supercontinuum white light source for outputting broad-spectrum excitation Light; the monochromatic unit, used to filter the broad-spectrum excitation light into monochromatic light; the optical path coupling and output module, used to irradiate the monochromatic light to the sample surface, and excite to obtain Raman signal light; the signal detection module is used to The Raman signal light is received for detection, and the Raman spectrum of the sample is obtained. The monochromatic unit includes a grating and a first reflector. Adjusting the deflection angle of the grating and the first reflector relative to the supercontinuum white light source can change the position where monochromatic light of different wavelengths is reflected to the aperture. A supercontinuum white light source is used to provide broad-spectrum excitation light, and the tunable Raman spectrum with a wavelength of excitation light from 400 to 2400nm can be measured. Therefore, a wide range of Raman can be easily realized without using an expensive and inconvenient wavelength tunable laser. Resonance Raman spectroscopy measurements.

Description

Raman Spectroscopy Test System

technical field

The utility model belongs to the technical field of microscopic spectrometers, in particular to a Raman spectrum testing system.

Background technique

As an efficient and non-destructive characterization technique for detecting material components and lattice vibrations, Raman spectroscopy is widely used in many fields such as physics, chemistry, biomedicine, and materials science. Resonance Raman spectroscopy is based on conventional Raman spectroscopy, using excitation light that resonates with the energy level of the sample to be tested to excite the Raman signal, which can make the Raman signal of the sample to be tested resonantly enhanced by several orders of magnitude. In this way, the relevant electronic band structure information of the sample to be tested can be obtained by measuring the curve of the Raman signal intensity changing with the wavelength of the excitation light (hereinafter referred to as "resonance profile"). Gas, ion or solid-state pump lasers commonly used today generally have discrete single or multiple laser wavelengths. Therefore, to test the resonance profile of the Raman spectrum of a material, a large number of lasers covering a large wavelength range are often required. In addition, it is necessary to accurately determine the electronic band structure information of the material through the Raman spectral resonance profile.

Previous Raman spectral resonance profiles are usually measured on a triple-grating Raman spectrometer using a tunable laser as the excitation light source. Tunable lasers such as Ti:Sapphire lasers or dye lasers. The three-grating Raman spectrometer can filter the Rayleigh signal light well by making the first two-stage grating work in the subtraction mode, and in the visible light range, no notch or sideband filter is required, and the three-grating is used Raman spectrometers can test Raman signals as low as 5 wavenumbers. However, due to the efficiency of devices such as gratings and mirrors, the transmittance of the spectral signal of a three-grating Raman spectrometer is usually only 1/10 of that of a single-grating Raman spectrometer.

With the advancement of science and technology, Raman filters such as notch filters and sideband filters for different excitation wavelengths have been manufactured. Since the Raman filter has a cut-off rate of up to 10 ^-6 for the Rayleigh signal light, it is unnecessary to use a multi-level grating subtraction mode to filter the Rayleigh signal light. A single grating spectrometer combined with a Raman filter can also be used to test the Raman spectrum signal, and has a high signal transmittance. Therefore, the single grating Raman spectrometer has become the mainstream equipment for the current Raman spectroscopy test.

However, there are also problems in testing the resonance profile of Raman spectroscopy with a single-grating Raman spectrometer. Conventional Raman filters are only designed for a specific excitation wavelength. When the normal working angle is exceeded, the working wavelength range of the s-wave and p-wave of the scattered light will be different, so it cannot continue to be used in Raman spectroscopy. In this way, the laser of each wavelength must be equipped with a sideband filter of the corresponding working wavelength in order to use a single grating spectrometer to test the Raman spectrum. This makes testing the resonance profiles of Raman spectroscopy using lasers of discrete wavelengths very expensive. For a continuous tunable laser, in principle, an infinite number of Raman filters are required to complete the test of the fine Raman spectral resonance profile, and custom non-standard Raman filters are very expensive, which limits the single-grating Raman Application of Mann spectrometer in Raman spectrum resonance profile test.

Utility model content

Based on the above technical problems, the main purpose of the present disclosure is to propose a Raman spectroscopy testing system for solving at least one of the above technical problems.

In order to achieve the above purpose, the present disclosure proposes a Raman spectroscopy testing system, including a broad-spectrum monochromatization module, an optical path coupling and output module, and a signal detection module, wherein:

Broad Spectrum Monochromation Module, including:

Supercontinuum white light source for outputting broad-spectrum excitation light;

a monochromatization unit for filtering broad-spectrum excitation light into monochromatic light;

The optical path coupling and output module is used to irradiate the monochromatic light to the sample surface to excite and obtain Raman signal light;

The signal detection module is configured to receive and detect the Raman signal light to obtain the Raman spectrum of the sample.

In some embodiments of the present disclosure, the above-mentioned monochromatization unit includes:

Broadband pass filter, used to select a broad-spectrum excitation light in a certain wavelength range;

A grating is used to disperse broad-spectrum excitation light in a certain wavelength range into monochromatic light of different wavelengths;

The diaphragm is used to filter monochromatic light of different wavelengths to obtain monochromatic light irradiated on the surface of the sample.

In some embodiments of the present disclosure, the above-mentioned monochromatic unit further includes a first reflector, configured to reflect monochromatic light of different wavelengths to the diaphragm.

In some embodiments of the present disclosure, the above-mentioned grating and the first reflector are placed on the same rotatable bracket, which is used to adjust the deflection angle of the grating and the first reflector relative to the supercontinuum white light source, thereby changing the single The position at which colored light is reflected to the diaphragm.

In some embodiments of the present disclosure, the above-mentioned monochromatic light unit further includes at least one tunable narrow bandpass filter, and each tunable narrow bandpass filter is placed on a rotatable bracket capable of adjusting its position and deflection angle on, used to purify monochromatic light that hits the sample surface.

In some embodiments of the present disclosure, the band-pass range of the above-mentioned wide-band pass filter is greater than twice the full width at half maximum of the resonance profile of the Raman spectrum.

In some embodiments of the present disclosure, the working range of the above-mentioned grating matches the range of the resonance profile of the Raman spectrum.

In some embodiments of the present disclosure, the above-mentioned grating includes a transmission grating or a reflection grating.

In some embodiments of the present disclosure, the optical path coupling and output module includes:

The beam splitter is used to make the monochromatic light irradiated on the surface of the sample enter the microscope objective lens;

The microscope objective lens is used to focus the monochromatic light irradiated on the sample surface to the sample surface, excite and obtain Raman signal light, and collect the Raman signal light reflected by the sample surface and transmit it to the beam splitter;

The focusing lens is used to focus the Raman signal light to be incident on the signal detection module.

In some embodiments of the present disclosure, the above-mentioned beam splitter is placed on a vertical two-dimensional angle adjustment frame for collimating the monochromatic light irradiated on the surface of the sample to enter the microscope objective lens.

In some embodiments of the present disclosure, the above-mentioned optical path coupling and output module further includes:

At least one tunable sideband filter, located between the microscope objective lens and the focusing lens, is used to filter out the Rayleigh signal light carried when the sample surface reflects the Raman signal light, so as to obtain pure Raman signal light.

In some embodiments of the present disclosure, the above-mentioned at least one tunable sideband filter is fixed on a two-dimensional vertically adjustable frame arranged on a rotatable bracket, so as to adjust the working angle of the at least one tunable sideband filter Make fine adjustments.

In some embodiments of the present disclosure, the transmittance of the tunable sideband filter to Raman signal light is greater than or equal to 90%; the transmittance to Rayleigh signal light is less than 10 ^-6 .

In some embodiments of the present disclosure, the above-mentioned optical path coupling and output module further includes:

At least one second reflector, each second reflector is placed on a vertical two-dimensional angle adjustment frame, used to reflect the monochromatic light irradiated on the sample surface to the center of the beam splitter;

At least one third mirror is used to make the Raman signal light reflected by the sample surface through the beam splitter enter the focusing lens.

In some embodiments of the present disclosure, the above-mentioned focusing lens is placed on a three-dimensional adjustment frame, and by adjusting the three-dimensional adjustment frame, the Raman signal light can be precisely focused and incident on the signal detection module.

In some embodiments of the present disclosure, the above-mentioned signal detection module includes:

The single grating spectrometer is used to receive the Raman signal light for detection and obtain the Raman spectrum of the sample.

The Raman spectroscopy testing system proposed in the present disclosure has the following beneficial effects:

1. The supercontinuous white light source is used to provide broad-spectrum excitation light, so that it can provide light with a wavelength of 400-2400nm, so there is no need to use wavelength-tunable lasers that are expensive and inconvenient to operate, that is, it is convenient to select monochromatic light of different wavelengths ; and because the monochromatic unit adopts a grating and a diaphragm, the monochromatic light with good monochromaticity can be easily obtained, so that the half width of the output monochromatic light is less than 1mm; therefore, the design of the broad-spectrum monochromatization module is simple and practical, and can realize Low cost, simple operation, low technical difficulty and other effects;

2. By adjusting the deflection angle of the grating and the first reflector relative to the supercontinuum white light source, the position of the monochromatic light of different wavelengths reflected to the diaphragm can be changed, so that the diaphragm can be filtered to obtain the light of different wavelengths irradiated on the sample surface Monochromatic light; and by setting at least one tunable narrow bandpass filter to purify the monochromatic light and a tunable sideband filter, it is convenient to switch monochromatic light of different wavelengths to test the resonance profile of the Raman spectrum, Accurately obtain the electronic band structure information of the sample;

3. The optical coupling and output module adopts the tunable sideband filter on the two-dimensional vertically adjustable frame placed on the rotatable bracket. By changing its working angle, the optimal adjustment of its working angle is realized, so as to achieve a suitable The cut-off wavenumber allows most of the Raman signal light to pass through, effectively blocking the Rayleigh signal light, thereby improving the accuracy of the entire system test.

4. In this disclosure, reflectors, beam splitters, and tunable sideband filters are all fixed on two-dimensional vertically adjustable frames, and each adjustable frame can realize fine adjustment in two-dimensional directions. Part of the two-dimensional vertically adjustable frame is placed on a rotatable support, and the rotatable support is pluggably placed on a pillar fixed on the base of the spectrometer. Based on this, when switching monochromatic light of different wavelengths and changing the cut-off sideband of the tunable sideband filter, the optical path can be collimated and adjusted quickly;

5. The Raman spectroscopy test system disclosed in the present disclosure has the advantages of low cost, continuously adjustable excitation light and filter cut-off sidebands, easy operation, reasonable optical path layout, and strong scalability.

Description of drawings

FIG. 1 is a schematic structural diagram of a resonance Raman spectroscopy testing system proposed by an embodiment of the present disclosure;

Fig. 2 is the spectrogram of the monochromatic light emitted by the broad-spectrum monochromatization module in Fig. 1;

Fig. 3 is the white light transmission spectrum of the tunable sideband filter TLF in Fig. 1 at a certain working angle;

Figure 4 is the Raman spectrum of the characteristic peak at 520.6cm ^-1 measured by the Raman spectrometer at the working angle in Figure 3;

Fig. 5 is the Raman spectrum of the G-mode (~1580cm ^-1 ) of the angled double graphene t(1+1) LG measured by the Raman spectrum testing system in Fig. 1;

Fig. 6 is the resonance profile of the Raman intensity of the G-mode of the double graphene t(1+1) LG normalized to the single-layer graphene measured by the Raman spectroscopy test system in Fig. 1 .

detailed description

In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

With the gradual progress of coating technology, a special sideband filter, namely tunable sideband filter, has been manufactured. By changing the working angle of the tunable sideband filter, its cut-off sideband will be continuously adjustable, and in the adjustment process, there is no difference between the cut-off wavelengths of s-wave and p-wave, so that it can be used in a wider wavelength range. In the visible light range, the adjustable range of the tunable sideband filter can reach 50-100nm, and the adjustable range is related to the working wavelength. The working range of a single tunable sideband filter is even sufficient for several dye lasers. Therefore, if the tunable sideband filter is applied to the Raman spectrum testing system, the cost of using a single grating Raman spectrometer and a tunable laser to test the Raman spectrum resonance profile can be greatly reduced. However, current wavelength tunable lasers are very expensive or inconvenient to operate. Therefore, it is very necessary to find a cost-effective and easy-to-operate tunable alternative excitation light source for Raman spectrum resonance profile testing.

The supercontinuum white light source (Supercontinuum laser) has been developed to provide unpolarized composite light as wide as the white light spectrum, and its coverage can be as wide as the wavelength range of 400-2400nm. Its total output optical power can reach more than ten watts, and its brightness is very high. At the same time, its beam divergence angle is very small, and its full emission angle can be less than 1mrad. Its collimation is very good, which can be compared with most ion or gas lasers. Therefore, such a supercontinuum light source can replace multiple light sources, such as single-line lasers, white light lamps, superradiant broadband light sources (SLEDs), etc. For such an excitation light source with high brightness and very small beam divergence angle, if we can obtain monochromatic light with continuously adjustable wavelength and stable output, and couple it into a microscopic confocal single-grating Raman spectrometer, it will be possible As an excitation source with a wide tuning range for testing Raman spectroscopy. This light source has a maintenance-free life of thousands of hours. Compared with various expensive lasers, it will greatly reduce the cost and technical difficulty of Raman spectroscopy resonance profile testing.

Therefore, how to design a tunable resonance Raman spectroscopy testing system based on a supercontinuum white light source with a simple structure, easy replacement of optical components with working wavelengths, and the use of tunable sideband filters is a challenge for the majority of Raman spectroscopy workers. One of the spectroscopic technical problems expected to be solved.

Therefore, this disclosure proposes a Raman spectrum testing system, including a broad-spectrum monochromatization module, an optical coupling and output module, and a signal detection module, wherein:

Broad Spectrum Monochromation Module, including:

Supercontinuum white light source for outputting broad-spectrum excitation light;

a monochromatization unit for filtering broad-spectrum excitation light into monochromatic light;

The optical path coupling and output module is used to irradiate the monochromatic light to the sample surface to excite and obtain Raman signal light;

The signal detection module is used to receive and detect the Raman signal light to obtain the Raman spectrum of the sample.

Since the supercontinuum white light source is used to provide broad-spectrum excitation light, it can provide light with a wavelength of 400-2400nm, so it is not necessary to use an expensive and inconvenient wavelength-tunable laser, that is, it is convenient to select monochromatic light of different wavelengths.

In some embodiments of the present disclosure, the above-mentioned monochromatization unit includes:

Broadband pass filter, used to select a broad-spectrum excitation light in a certain wavelength range;

A grating is used to disperse broad-spectrum excitation light in a certain wavelength range into monochromatic light of different wavelengths;

The diaphragm is used to filter monochromatic light of different wavelengths to obtain monochromatic light irradiated on the surface of the sample.

Since the monochromatic unit adopts a grating and a diaphragm, monochromatic light with good monochromaticity can be easily obtained, so that the half-width of the output monochromatic light is less than 1mm; therefore, the design of the broad-spectrum monochromatization module is simple and practical, and can achieve low cost , simple operation, low technical difficulty and other effects.

In some embodiments of the present disclosure, the above-mentioned monochromatic unit further includes a first reflector, configured to reflect monochromatic light of different wavelengths to the diaphragm.

In some embodiments of the present disclosure, the above-mentioned grating and the first reflector are placed on the same rotatable bracket, which is used to adjust the deflection angle of the grating and the first reflector relative to the supercontinuum white light source, thereby changing the single The colored light is reflected to the position of the diaphragm; thus, the diaphragm can be filtered to obtain monochromatic light of different wavelengths irradiated on the surface of the sample, and it is convenient to switch monochromatic light of different wavelengths for Raman spectrum testing.

In some embodiments of the present disclosure, the above-mentioned monochromatic light unit further includes at least one tunable narrow bandpass filter, and each tunable narrow bandpass filter is placed on a rotatable bracket capable of adjusting its position and deflection angle above, used to purify the monochromatic light irradiated on the surface of the sample; thus, the test system of this embodiment can accurately obtain the sample information.

In some embodiments of the present disclosure, the band-pass range of the above-mentioned wide-band pass filter is greater than twice the full width at half maximum of the resonance profile of the Raman spectrum.

In some embodiments of the present disclosure, the working range of the above-mentioned grating matches the range of the resonance profile of the Raman spectrum.

In some embodiments of the present disclosure, the above-mentioned grating includes a transmission grating or a reflection grating; different types of gratings require designing different optical paths to realize the functions of the Raman spectroscopy testing system of this embodiment; preferably, a transmission grating is used.

In some embodiments of the present disclosure, the optical path coupling and output module includes:

The beam splitter is used to make the monochromatic light irradiated on the surface of the sample enter the microscope objective lens;

The microscope objective lens is used to focus the monochromatic light irradiated on the sample surface to the sample surface, excite and obtain Raman signal light, and collect the Raman signal light reflected by the sample surface and transmit it to the beam splitter;

The focusing lens is used to focus the Raman signal light to be incident on the signal detection module.

In some embodiments of the present disclosure, the above-mentioned beam splitter is placed on a vertical two-dimensional angle adjustment frame for collimating the monochromatic light irradiated on the surface of the sample to enter the microscope objective lens.

In some embodiments of the present disclosure, the above-mentioned optical path coupling and output module further includes:

At least one tunable sideband filter, located between the microscope objective lens and the focusing lens, is used to filter out the Rayleigh signal light carried when the sample surface reflects the Raman signal light, so as to obtain pure Raman signal light.

In some embodiments of the present disclosure, the above-mentioned at least one tunable sideband filter is fixed on a two-dimensional vertically adjustable frame arranged on a rotatable bracket, so as to adjust the working angle of the at least one tunable sideband filter Make fine adjustments.

Therefore, since the optical coupling and output module adopts the tunable sideband filter placed on the two-dimensional vertically adjustable frame on the rotatable bracket, by changing its working angle, the optimal adjustment of its working angle is realized, so as to achieve Appropriate cut-off wavenumber allows most of the Raman signal light to pass through, effectively blocking the Rayleigh signal light, thereby improving the accuracy of the entire system test

In some embodiments of the present disclosure, the transmittance of the tunable sideband filter to Raman signal light is greater than or equal to 90%; the transmittance to Rayleigh signal light is less than 10 ^-6 .

In some embodiments of the present disclosure, the above-mentioned optical path coupling and output module further includes:

At least one second reflector, each second reflector is placed on a vertical two-dimensional angle adjustment frame, used to reflect the monochromatic light irradiated on the sample surface to the center of the beam splitter;

At least one third mirror is used to make the Raman signal light reflected by the sample surface through the beam splitter enter the focusing lens.

In some embodiments of the present disclosure, the above-mentioned focusing lens is placed on a three-dimensional adjustment frame, and by adjusting the three-dimensional adjustment frame, the Raman signal light can be precisely focused and incident on the signal detection module.

In some embodiments of the present disclosure, the above-mentioned signal detection module includes:

The single grating spectrometer is used to receive the Raman signal light for detection and obtain the Raman spectrum of the sample.

In some embodiments of the present disclosure, the signal detection module includes a single grating spectrometer and a corresponding control circuit for detecting the pure Raman signal light obtained by the optical path coupling and output module to obtain the Raman spectrum of the sample SMP. The single grating spectrometer GPY in the signal detection module includes a slit SLT, a mirror M5, a mirror M6, a grating GRT and a detector CCD, wherein the Raman signal light from the slit SLT is incident on the mirror MA, and passes through the mirror The signal light reflected by MA is irradiated on the grating GRT, and the signal light dispersed by the grating GRT is collected by the mirror MB and reflected to the detector CCD for detection.

In the present disclosure, the reflector, the beam splitter, and the tunable sideband filter are all fixed on a two-dimensional vertically adjustable frame, and each adjustable frame can realize fine adjustment in two-dimensional directions. Part of the two-dimensional vertically adjustable frame is placed on a rotatable support, and the rotatable support is pluggably placed on a pillar fixed on the base of the spectrometer. Based on this, when switching monochromatic light of different wavelengths and changing the cut-off sideband of the tunable sideband filter, the optical path can be collimated and adjusted quickly.

In addition, in some embodiments of the present disclosure, when the Raman spectroscopy testing system is used for testing, a wavelength measuring device is also used to measure the wavelength of the monochromatic light passing through the aperture; preferably, the wavelength measuring device It can be a fiber optic spectrometer or other equipment that can measure the wavelength of light.

Specifically, the present disclosure is implemented in this way, and its method steps are:

1. Select a suitable broadband filter BBF, select a certain wavelength range from the continuum of the supercontinuum white light source SCL, and ensure that the working range of other optical components in the device covers the wavelength range;

2. Rotate the rotatable support where the transmission grating TG and the first reflector M1 are located, change the deflection angle of the transmission grating TG and the first reflector M1 relative to the incident light path, and change the supercontinuous white light source SCL after being split by the transmission grating TG - where the spectral band of order 1 reaches on the aperture APT. Adjust the deflection angle of two special tunable narrow bandpass filters TBF1 and TBF2 relative to the incident light to purify the monochromatic light. The wavelength of monochromatic light emitted through the tunable narrow bandpass filters TBF1 and TBF2 is measured by a monochromatic light wavelength measuring device WLM.

3. By configuring the first reflector, the monochromatic light emitted from the broad-spectrum monochromatization module is incident on the second reflector M2, and reflected to the beam splitter BS via M3 in the second reflector, and then split The monochromatic light reflected by the beam detector BS is focused on the surface of the sample SMP through the microscope objective lens OBJ. At the same time, the monochromatic reflected light and Raman signal light from the sample SMP are collected by the microscope objective lens OBJ and then incident on the beam splitter BS, and then reflected by the third mirror M4 to the tunable sideband filter TLF. According to the wavelength of the incident monochromatic light, turn the tunable sideband filter TLF on the rotatable bracket to change the deflection angle of the tunable sideband filter TLF relative to the optical path, and adjust the tunable sideband filter TLF's cut-off sidebands to suitable wavenumbers. The tunable sideband filter TLF filters and attenuates the reflected light of monochromatic light (that is, the Rayleigh signal light) to at least 1/10 ⁶ of the original, allowing most of the Raman signal light to pass through, and After being focused by the focusing lens LNS into the slit SLT of the single grating spectrometer, it is then detected by the single grating spectrometer.

4. Repeat the above steps 2 and 3, only need to make small adjustments to the optical components in the optical path, and then the test of the next monochromatic wavelength can be carried out.

The Raman spectroscopy testing system proposed in the present disclosure will be described in detail below through specific examples.

Example

As shown in FIG. 1 , this embodiment discloses a tunable resonance Raman spectroscopy test system based on a supercontinuum white light source, including a broad-spectrum monochromatization module 10 , an optical coupling and output module 20 and a signal detection module 30 .

As a preferred embodiment, utilize this tunable resonance Raman spectrum test system based on supercontinuum white light source, test the G-mode Raman spectrum of double graphene t(1+1)LG and monolayer graphene, obtain two The Raman spectrum resonance profile whose ratio varies continuously with the excitation wavelength of monochromatic light at 550nm-700nm.

Wherein, the broad-spectrum monochromatization module 10 includes at least a supercontinuum white light source (SCL) 101, a broadband filter (BBF) 102, a transmission grating (TG) 103, a reflector M1 (104) and an aperture ( APT) 105, the broad-spectrum monochromatization module 10 is used to emit and select monochromatic light. And it also includes at least two special tunable narrow bandpass filters (TBF1) 106 and (TBF2) 107 for purifying monochromatic light; optionally includes a monochromatic light wavelength measuring device (WLM) 108 for The wavelength of monochromatic light after passing through the aperture (APT) 105 is measured.

Preferably, the supercontinuum white light source (SCL) 101 in the broad-spectrum monochromatization module 10 uses the SuperK series supercontinuum spectrum white light source EXW-12 produced by Denmark NKTPhotonics Company, which has a very wide spectral range and can realize 400- 2400nm spectral output, visible light output power up to 1.2W, easy to operate, and can achieve long-term stable work.

A broadband filter (BBF) 102 is used to select a spectrum of a certain wavelength range from the continuum of the supercontinuum white light source (SCL) 101, so as to ensure that the working range of other optical components in the device covers the wavelength range.

As preferably, the broadband pass filter (BBF) 102 in the broad-spectrum monochromatization module 10 has used the Super Cold Filter super cold filter YSC1100 of Asahi-Spectra Company and the BrightLine FullSpectrum Blocking single-band bandpass filter BroadLine FullSpectrum Blocking single-band bandpass filter of Semrock Company Combination of filters FF01-632/148-25. The transmission range of the broadband ultra-cold filter is 400-1000nm, and the average transmittance is 70%, which is used to filter the light with a wavelength above 1000nm emitted from the supercontinuum white light source (SCL) 101 . The central wavelength of the single bandpass filter is 632nm, the transmission bandwidth is 148nm, and the transmittance is 93%. The operating range of the components covers this wavelength range.

The transmission grating (TG) 103 and the reflection mirror (M1) 104 in the broad-spectrum monochromatization module are fixed on a rotatable bracket, so that their deflection angles relative to the incident light path can be adjusted. When the transmission grating (TG) 103 and the reflection mirror (M1) 104 are placed as shown in Figure 1, the -1 order spectral line of the supercontinuum white light source 101 reaches the aperture (APT) 105 through the reflection mirror (M1) 104, by changing the transmission grating (TG) 103 and reflector (M1) 104 relative to the deflection angle of the incident light source, change the position of the spectral band composed of -1 order to reach the position on the aperture (APT) 105, and use the aperture (APT) 105 to separate the monochromatic Light.

Preferably, the transmission grating (TG) 103 in the broad-spectrum monochromatization module uses Ibsen FusedSilica Transmission Gratings VIS-1379-911, the operating wavelength range is 400-800nm, and the grating resolution is 1379mm ^-1 .

Two special tunable narrow bandpass filters (TBF1) 106 and (TBF2) 107 in the broad-spectrum monochromatization module 10 are used to filter stray light and achieve the purpose of purifying monochromatic light.

As a preference, two special tunable narrow bandpass filters (TBF1) 106 and (TBF2) 107 in the broad-spectrum monochromatization module 10 use Semrock company tunable bandpass filter TBP01-561/14 (tunable central wavelength range 501.5nm～561.0nm, bandwidth 14nm), TBP01-617/14 (tunable central wavelength range 550nm～617nm, bandwidth 13nm), TBP01-628/14 (adjustable central wavelength range 561nm～627nm, bandwidth 14nm), TBP01-697/13 (adjustable central wavelength range 618.5nm～697.0nm, bandwidth 13nm), TBP01-704/13 (adjustable central wavelength The range is 627.7nm～703.8nm, and the bandwidth is 13nm), which need to be combined according to actual needs. By properly adjusting its deflection angle relative to the incident light path, changing the central wavelength of the tunable narrow bandpass filter, and using the intersection of the bandpass bands of the two tunable narrow bandpass filters to achieve the purpose of purifying monochromatic light .

Further, two special tunable narrow bandpass filters (TBF1) 106 and (TBF2) 107 are respectively placed on a rotatable bracket, which can finely adjust the position and deflection angle of the tunable narrow bandpass filters.

The optical path coupling and output module 20 includes at least two second mirrors (M2) 201 and (M3) 202, a beam splitter (BS) 203, a microscope objective lens (OBJ) 204, a third mirror (M4) 205, and Tunable sideband filter (TLF) 206 and focusing lens (LNS) 207, used for the monochromatic light that described broad-spectrum monochromatization module obtains is reflected to splitter through two reflection mirrors (M2) 201, (M3) 202 The center of the beam splitter (BS) 203, the beam splitter (BS) 203 guides the monochromatic light beam to the microscopic objective lens (OBJ) 204, focuses the sample (SMP) through the microscopic objective lens (OBJ) 204 and irradiates it, And allow the reflected light (ie Rayleigh signal light) and Raman signal light after irradiating the sample (SMP) to return to the center of the beam splitter (BS) 203 after being collected by the microscope objective lens (OBJ) 204, and pass through the adjustable side A filter (TLF) 206 is used to obtain pure Raman signal light, which is then converged to a subsequent signal detection module by a focusing lens (LNS) 207 .

Preferably, in the optical path coupling and output module 20, the second reflector (M2) 201, (M3) 202 and the third reflector (M4) 205 are all fixed on the two-dimensional vertically adjustable frame, so that their angles are uniform Two-dimensional adjustable; adjust the second mirror (M3) 202 so that the monochromatic beam can be incident on the center of the beam splitter (BS) 203 .

Preferably, in the optical coupling and output module 20, the beam splitter (BS) 203 and the tunable sideband filter (TLF) 206 are respectively arranged on two-dimensional vertically adjustable racks in a pluggable manner, so that Precise adjustment of its position and deflection angle.

Further, the reflectance of the beam splitter (BS) 203 is 50%, and the transmittance is 50%. The two-dimensional vertically adjustable frame of the beam splitter (BS) 203 also includes adjustment threads, which can further finely adjust the position and angle of the optical filter supported on the two-dimensional vertically adjustable frame.

As preferably, what the tunable sideband filter (TLF) 206 uses is Semrock's VersaChromeEdge ^TM tunable longpass filter tunable longwave sideband filter TLP01-628 (tunable sideband wavelength is 561nm～628nm) and TLP01- 704 (tunable sideband wavelength is 628nm ~ 704nm), its transmittance > 90%. Its two-dimensional vertically adjustable frame is fixed on a rotatable bracket, and the rotatable bracket is pluggably placed on the pillar fixed on the base of the spectrometer, and can adjust the position and position of the tunable sideband filter (TLF) 206 The deflection angle can be further fine-tuned.

Preferably, in the optical coupling and output module 20, the microscope objective (OBJ) 204 uses a 100x Leica microscope objective (numerical aperture NA=0.9), and the diameter of the monochromatic spot reaching the sample SMP is 1-2 μ2.

Preferably, the focus lens (LNS) 207 is placed on the three-dimensional translation adjustment frame, and by adjusting the three translation axes of the three-dimensional translation adjustment frame, not only the position of the focus lens 207 can be adjusted in the two-dimensional vertical direction, but also the position of the focus lens 207 can be adjusted on the optical axis. The direction adjusts the position of the converging lens 207 so that the Raman signal light can be accurately incident and focused on the slit (SLT) 301 of the signal detection module 30 for detection by the signal detection module.

The single grating spectrometer in the signal detection module 30 includes a slit (SLT) 301, a fourth mirror (M5) 302, a fifth mirror (M6) 303, a grating (GRT) 304 and a detector (CCD) 305, wherein The Raman signal light from the slit (SLT) 301 is incident on the fourth mirror (M5) 302, and the signal light reflected by the fourth mirror (M5) 302 is irradiated on the grating (GRT) 304, and passes through the grating (GRT) ) 304 dispersed signal light is collected by the fifth mirror (M6) 303 and reflected to the detector (CCD) 305 for detection.

The signal acquisition and analysis process of the Raman spectrum of the present embodiment comprises the following steps:

Step 1. Select a suitable broadband filter (BBF) 102, select a certain wavelength range from the continuum of the supercontinuum white light source (SCL) 101, and ensure that the working range of other optical elements in the device covers this wavelength range.

Step 2, rotate the rotatable support where the transmission grating (TG) 103 and the first reflection mirror (M1) 104 are located, and change the deflection angle of the transmission grating (TG) 103 and the first reflection mirror (M1) 104 relative to the incident light path, Change the position where the -1st order spectral band of the supercontinuum white light source (SCL) 101 reaches the aperture (APT) 105 after being split by the transmission grating (TG) 103 . The deflection angles of the two special tunable narrow bandpass filters (TBF1) 106 and (TBF2) 107 relative to the incident light are adjusted to purify the monochromatic light. A monochromatic light wavelength measuring device (WLM) 108 is used to measure the wavelength of the monochromatic light emitted through the tunable narrow bandpass filters (TBF1) 106 and (TBF2) 107 .

Step 3. After configuring the first reflector (M1) 103, the monochromatic light emitted from the broad-spectrum monochromatization module is incident on the second reflector (M2) 201, and reflected by the second reflector (M3) 202 to the beam splitter The beam splitter (BS) 203 , and then the monochromatic light reflected by the beam splitter (BS) 203 is focused to the surface of the sample SMP through the microscope objective lens (OBJ) 204 . At the same time, the microscopic objective lens (OBJ) 204 collects the monochromatic light reflection light (ie Rayleigh signal light) and the Raman signal light from the sample SMP to be incident on the beam splitter (BS) 203 after being collected by the microscopic objective lens (OBJ) 204 , and then reflected to the tunable sideband filter (TLF) 206 via the third mirror (M4) 205 . According to the wavelength of the incident monochromatic light, turn the tunable sideband filter (TLF) 206 on the rotatable bracket to change the deflection angle of the tunable sideband filter (TLF) 206 relative to the optical path, and adjust the The cut-off sideband of the sideband filter (TLF) 206 is tuned to the appropriate wavenumber. The tunable sideband filter (TLF) 206 filters and attenuates the reflected light of the monochromatic light (that is, the Rayleigh signal light) to at least 1/10 ⁶ of the original light, so that most of the Raman signal light is transmitted through the focusing lens (LNS) 207 and focus into the slit (SLT) 301 of the single grating spectrometer for detection by the single grating spectrometer.

Step 4. Repeat the above steps (2) and (3), and only need to make small adjustments to the optical elements in the optical path, and then the test of the next monochromatic wavelength can be carried out.

Utilize the Raman spectrum testing system of the present embodiment, test (1 layer+1 layer) the G-mode Raman spectrum of the double graphene of corner and single-layer graphene, have used 100 times of Leica microscopic objective lenses, 600 ruled gratings, The entrance slit width of the spectrometer is 100 μm. As shown in Figure 2, the spectrum of the monochromatic light with a wavelength of 619.5nm emitted by the broad-spectrum monochromatization module is shown. It can be seen from the figure that the half width of the monochromatic light is less than 0.5nm, which shows that it has a very good monochromaticity. As shown in Figure 3 and Figure 4, it is the white light transmission spectrum of the tunable sideband filter (TLF) 206 at a certain deflection angle and the characteristic of the silicon wafer at 520.6 cm ^-1 measured by the Raman spectrometer at this time From the Raman spectrum of the peak, it can be seen that the tunable sideband filter (TLF) 206 can cut off to 200cm ^-1 , and there is no obvious spurious signal in the spectrum above 200cm ^-1 . As shown in FIG. 5 , it is the Raman spectrum of the G mode of the twisted double graphene at 1580 cm ^-1 measured by the Raman spectrum testing system of this embodiment. Because the intensity of the Raman signal is related to the laser power, the excitation light power needs to be normalized to obtain the resonance intensity spectrum. In this example, the G-mode Raman intensity of the single-layer graphene G-mode at 1580 cm ⁻¹ is used for normalization. As shown in Figure 6, the Raman intensity of the G-mode at 1580 cm ^-1 of the corner double graphene measured by the Raman spectroscopy test system of the present embodiment is relative to the Raman intensity of the G-mode of the single-layer graphene relative to the monochromatic The relationship between the change of the excitation light, so as to obtain the resonance intensity spectrum of the corner double graphene with the excitation wavelength of the monochromatic light in the range of 550nm to 700nm.

The above examples illustrate that the Raman spectroscopy test system designed in the present disclosure can not only obtain monochromatic light with continuously adjustable wavelength and stable output, but also utilize the adjustable cut-off sideband of the tunable sideband filter to make the resonance intensity spectrum The measurement is realized in a commercial single-grating Raman spectrometer, which is simple and practical in design, easy to operate, reasonable in optical path arrangement and strong in scalability. The disclosure can make up for the technical deficiency that commercial Raman spectrometers cannot meet the requirements of resonance intensity spectrum measurement, and promote the application of micro-confocal Raman spectroscopy in material research.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above descriptions are only specific embodiments of the utility model and are not intended to limit the utility model. For new models, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims (12)

1. A Raman spectrum testing system, comprising broad-spectrum monochromatization module, optical path coupling and output module and signal detection module, is characterized in that: Broad Spectrum Monochromation Module, including: Supercontinuum white light source for outputting broad-spectrum excitation light; a monochromatization unit, configured to filter the broad-spectrum excitation light into monochromatic light; The optical path coupling and output module is used to irradiate the monochromatic light to the surface of the sample for excitation to obtain Raman signal light; The signal detection module is configured to receive and detect the Raman signal light to obtain the Raman spectrum of the sample. 2. Raman spectroscopy testing system as claimed in claim 1, is characterized in that, described monochromatic unit comprises: a broadband pass filter, used to select the broad-spectrum excitation light in a certain wavelength range; a grating, used to disperse the broad-spectrum excitation light in a certain wavelength range into monochromatic light of different wavelengths; The diaphragm is used to filter the monochromatic light of different wavelengths to obtain the monochromatic light irradiated on the surface of the sample. 3. Raman spectrum testing system as claimed in claim 2, is characterized in that, described monochromatization unit also comprises first mirror, is used for making the monochromatic light reflection of described different wavelengths to described aperture; Preferably, the grating and the first reflector are placed on the same rotatable support, and the rotatable support is used to adjust the deflection angle of the grating and the first reflector relative to the supercontinuum white light source to change the Monochromatic light of different wavelengths is reflected to the position of the diaphragm. 4. Raman spectrum test system as claimed in claim 3, is characterized in that, described monochromatic light unit also comprises at least one tunable narrow bandpass optical filter, each described tunable narrow bandpass optical filter is positioned at A rotatable stand capable of adjusting its position and tilting angle is used to purify the monochromatic light irradiated onto the sample surface. 5. Raman spectrum testing system as claimed in claim 2, is characterized in that, the band-pass range of described broadband pass filter is greater than twice of the full width at half maximum of described Raman spectrum resonance profile; The operating range of described grating It matches the range of the resonance profile of the Raman spectrum; preferably, the grating includes a transmission grating or a reflection grating. 6. Raman spectroscopy testing system as claimed in claim 1, is characterized in that, described optical path coupling and output module comprise: a beam splitter, used to make the monochromatic light irradiated on the sample surface incident on the microscope objective lens; a microscope objective lens, used to focus the monochromatic light irradiated on the sample surface to the sample surface, excite to obtain Raman signal light, and collect the Raman signal light reflected by the sample surface to be transmitted to the beam splitter; The focusing lens is configured to focus the Raman signal light to be incident on the signal detection module. 7. Raman spectroscopic testing system as claimed in claim 6, is characterized in that, described beam splitter is placed on the vertical two-dimensional angle adjustment frame, is used for collimating the monochromatic light that is irradiated to the sample surface incident on the microscope objective. 8. Raman spectroscopy test system as claimed in claim 6, is characterized in that, described optical path coupling and output module also comprise: At least one tunable sideband filter, located between the microscope objective lens and the focusing lens, is used to filter out the Rayleigh signal light carried when the sample surface reflects the Raman signal light. 9. Raman spectrum testing system as claimed in claim 8, is characterized in that, described at least one tunable sideband optical filter is fixed on the two-dimensional vertical adjustable frame that is arranged on rotatable support, is used for The working angle of the at least one tunable sideband filter is finely adjusted; preferably, the transmittance of the tunable sideband filter to the Raman signal light is greater than or equal to 90%; The transmittance of the signal light is less than 10 ^-6 . 10. Raman spectroscopy testing system as claimed in claim 6, is characterized in that, described optical path coupling and output module also comprise: At least one second mirror, each of which is placed on a vertical two-dimensional angle adjustment frame, is used to reflect the monochromatic light irradiated on the sample surface to the center of the beam splitter ; At least one third mirror is used to make the Raman signal light reflected by the sample surface through the beam splitter enter the focusing lens. 11. The Raman spectroscopy testing system according to claim 6, wherein the focusing lens is placed on a three-dimensional adjustment frame for precisely focusing the Raman signal light and incident on the signal detection module. 12. Raman spectroscopy testing system as claimed in claim 1, is characterized in that, described signal detection module comprises: The single grating spectrometer is used to receive the Raman signal light for detection and obtain the Raman spectrum of the sample.