JP2000101170A - Ld excitation solid-state laser device for simultaneously emitting blue light and green light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously emit economically blue light and green light by eliminating an LD excitation system. SOLUTION: A solid-state laser system 10B for blue light is excited by an excitation light from a common LD (semiconductor laser) system 10A to extract blue light. Meanwhile, a solid-state laser system 10C for green light is excited by the excitation light which is not absorbed by the solid-state laser system 10B for blue light and transmitted through it to take out green light at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LD (semiconductor laser) -excited solid-state laser device for simultaneously generating blue light and green light, and is used, for example, in stage lighting in entertainment, in the field of measurement or in physics and chemistry research. can do.

[0002]

2. Description of the Related Art As a technique for generating blue light and green light using a laser, for example, a blue laser and a green light are simultaneously generated using a gas laser such as an argon ion laser, and then the blue light and green light are generated using a dichroic mirror. Some are separated into light and emitted at the same time.

[0003] However, gas lasers such as argon lasers are currently changing to highly efficient LD (semiconductor laser) pumped solid-state lasers because of their extremely low efficiency and the need for large amounts of power and cooling water. .

When simultaneously generating blue light and green light with an LD-pumped solid-state laser, it is difficult to generate blue light and green light simultaneously and stably using one system of LD-pumped solid-state laser. In this case, two types of LD-excited solid-state lasers are used, as shown in FIG. 1, in which a solid-state laser system for green light and a solid-state laser for green light are respectively excited using individual LD excitation systems.

The LD-pumped solid-state lasers A and B shown in FIG.
LD pumping is performed by semiconductor lasers 1 and 1 as excitation light sources that generate semiconductor laser light 2 and condensing optics 3 and 3 that condense semiconductor laser light 2 and generate excitation light 4 having a desired beam diameter. Each system has a front side.

On the subsequent stage, a solid-state laser crystal 5 which generates a fundamental wave for blue light or green light by the excitation light 4 is provided.
An output side mirror 7 (7a, 7b) that constitutes an optical resonator for a fundamental wave between (5a, 5b) and the solid-state laser crystal 5.
b) and a nonlinear optical element 6 arranged between the solid-state laser crystal 5 and the output side mirror 7 to generate a second harmonic of the fundamental wave
(6a, 6b).

As the excitation light 4, for example, a laser beam having a wavelength of 808 nm is used.
946 nm wavelength from solid-state laser crystal 5 composed of AG
Alternatively, a fundamental wave having a wavelength of 1064 nm is excited, and the total reflection film 8 (8a, 8a,
8b), the fundamental wave resonates between the solid-state laser crystal 5 having the total reflection film 9 (9a, 9b) for the fundamental wave on the output end face, and the nonlinear optical element. 6, the wavelength 473 nm which is the second harmonic of the fundamental wave
And a green light component having a wavelength of 532 nm are extracted from the output side mirror 7.

However, the configuration in which the two systems of the LD-pumped solid-state laser for blue light and the LD-pumped solid-state laser for green light are arranged side by side, particularly, an LD (semiconductor laser) serving as an excitation light source and a semiconductor laser having a desired beam L due to the optical part that condenses light to the diameter
The D excitation system is expensive, and it is uneconomical to separately provide the LD excitation system for blue light and green light.

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention solves these problems in the prior art and, in particular, discloses a common LD.
(Semiconductor laser) L which generates blue light and green light simultaneously from the solid-state laser by the excitation light from the system, and simultaneously generates economical blue light and green light by eliminating one LD excitation system.
A D-pumped solid-state laser device is provided.

[0010]

In an LD-pumped solid-state laser device for simultaneously generating blue light and green light according to the present invention, a solid-state laser system for blue light is excited by excitation light from a common LD (semiconductor laser) system. It excites blue light and excites the green light solid-state laser system with the excitation light transmitted through the solid-state laser system for blue light without being absorbed, and simultaneously extracts green light.

According to the LD-pumped solid-state laser device of the present invention, an LD (semiconductor laser) serving as a pumping light source and an optical section for condensing the semiconductor laser light to a desired beam diameter are reduced by one system. In addition, since blue light and green light can be generated simultaneously with an inexpensive configuration, it is very economical.

Further, the LD (semiconductor laser) of the present invention
The excitation light from the system is supplied to a solid-state laser system for blue light of 60 to 8
With a configuration in which 0% is absorbed and 20 to 40% is transmitted, blue light whose light conversion efficiency is about 1/3 of that of green light is caused by other optical system variations, mounting accuracy errors, and the like. Even taking into account the difference between the two, the solid-state laser outputs of blue light and green light can be extracted in a state where they are almost equal.

As a means for transmitting part of the excitation light from the LD (semiconductor laser) system, if the thickness of the solid-state laser crystal used in the solid-state laser system for blue light is reduced, the solid-state laser system may be used. Since the absorption of the solid-state laser crystal with respect to the fundamental wavelength to be resonated is reduced to reduce the loss of the optical resonator, a higher solid-state laser output can be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An LD-pumped solid-state laser device according to the present invention, in which blue light and green light are simultaneously generated, will be described with reference to a block diagram of FIG. Reference numeral 10 includes a common LD excitation system 10A, a solid-state laser system 10B for blue light, and a solid-state laser system 10C for green light.

The LD excitation system 10A includes an LD as an excitation light source.
(Semiconductor laser) 11 and condensing optics 13
A (semiconductor laser) 11 generates a semiconductor laser beam 12 having a wavelength of 808 nm, and the semiconductor laser beam 12 is condensed by a condensing optical unit 13 to produce an excitation light 14 having a desired beam diameter. The laser system 10B is excited to generate blue light, and at the same time, the solid-state laser system 10C is excited to generate green light.

The solid-state laser system 10 B for blue light includes a first solid-state laser crystal 15, a dichroic mirror 18,
The first solid-state laser crystal 15, the dichroic mirror 18, and the end face of the resonance reflection mirror 20 have a wavelength 946.
Reflection surfaces 16, 17, 21 provided with a total reflection film (946HR coat) for nm are provided respectively.

The first solid-state laser crystal 15 is, for example, Nd:
Using YAG, the pumping light 14 having a wavelength of 808 nm is absorbed, and the second harmonic excites a fundamental wave having a wavelength of 946 nm corresponding to the blue light having a wavelength of 473 nm. The second harmonic acts on the solid-state laser crystal 23 so that the second harmonic has a wavelength of 1 corresponding to green light having a wavelength of 532 nm.
In order to excite the fundamental wave of 064 nm, the excitation light 14 is partially absorbed without being absorbed by 100%.

As means for transmitting part of the excitation light 14, for example, the excitation light 14 is
In order to transmit 0 to 40% (in a leaked state), for example, the thickness of Nd: YAG is reduced, and in particular, 70% of the excitation light 14 is absorbed and 30% is transmitted (in a leaked state). For example, a configuration in which the thickness of Nd: YAG is reduced to about 2 mm is desirable.

That is, the first solid-state laser crystal 15 made of Nd: YAG absorbs the excitation light 14 having the wavelength of 808 nm and also absorbs the fundamental wave having the wavelength of 946 nm.
If the thickness is set so that the AG absorbs the excitation light 14 by nearly 100% (for example, about 5 mm), the fundamental wave having a wavelength of 946 nm is absorbed by about 3%, thereby increasing the loss of the optical resonator and lowering the output. Nd: YA
The configuration in which the thickness of G is reduced is effective in reducing loss and obtaining a high output.

The blue light having a wavelength of 473 nm and the wavelength 53
Comparing the light conversion efficiency of 2 nm green light (solid laser output with respect to LD excitation light), the blue light efficiency (5 to 10%) is about 1/3 of the green light efficiency (20%). , Nd: YAG, the 30% excitation light 14 transmitted (leaked) from the first solid-state laser crystal 15 is used to excite the second solid-state laser crystal 23 for green light. In addition to the above, even when a difference between the two due to variations in the optical system, errors in the mounting accuracy, and the like is anticipated, the solid-state laser outputs of the blue light and the green light can be adjusted to be substantially equal and extracted.

The fundamental wave having a wavelength of 946 nm pumped by the first solid-state laser crystal 15 resonates with the reflection mirror 20 for resonance arranged at an orthogonal position via the reflection surface 17 of the dichroic mirror 18. At the same time, the wavelength is converted into a second harmonic having a wavelength of 473 nm by a non-linear optical crystal 19 such as an LBO crystal or KNbO ₃ disposed in the optical path and transmitted through the dichroic mirror 18 to transmit a wavelength of 473n.
It can be taken out as a solid-state laser output by m blue light.

The solid-state laser crystal 15 and the reflection surfaces 16 and 21 of the reflection mirror 20 constituting the optical resonator totally reflect the laser light having a wavelength of 946 nm, which is a fundamental wave of blue light, but have high gain. Wavelength 106 which is a fundamental wave of green light
Transmitting 30% or more of a 4 nm laser beam, thereby preventing resonance at a wavelength of 1064 nm on the solid-state laser system 10B for blue light and stabilizing resonance at a wavelength of 473 nm. Can be.

The solid-state laser system 10C for green light has a condenser lens 22, a second solid-state laser crystal 23, a dichroic mirror 25, a nonlinear optical crystal 27, and a reflection mirror 28 for resonance. The solid-state laser crystal 23, the dichroic mirror 25, and the end face of the reflection mirror for resonance 28 have a total reflection film (1064H
The reflective surfaces 24, 26, and 29 to which R coats are attached are provided, respectively.

A part of the excitation light 14 transmitted through the first solid-state laser crystal 15 without being absorbed, for example, 30% of the excitation light 1
4 is a dichroic mirror 1 on the solid-state laser system 10B side.
8, the light is condensed to a desired beam diameter by the condensing lens 22 to excite the second solid-state laser crystal 23. As the second solid-state laser crystal 23, for example, N
Using d: YAG or Nd: YVO ₄ , wavelength 808n
m and the second harmonic has a wavelength of 5
A fundamental wave having a wavelength of 1064 nm corresponding to 32 nm green light is excited.

The fundamental wave having a wavelength of 1064 nm is resonated with the reflection mirror for resonance 28 disposed at an orthogonal position via the reflection surface 26 of the dichroic mirror 25, and the LBO disposed in the optical path thereof. The wavelength is converted to a second harmonic having a wavelength of 532 nm by a nonlinear optical crystal 27 such as a crystal or a KTP crystal, and transmitted through the dichroic mirror 25 to be extracted as a solid-state laser output of green light having a wavelength of 532 nm.

As described above, in the LD-pumped solid-state laser apparatus according to the present invention, the solid-state laser system 10B for blue light and the solid-state laser system 10C for green light are simultaneously obtained (when blue light is generated) by the common LD pumping system. Excess LD light is used to generate green light) to excite it, and solid-state laser output light of both blue light and green light can be simultaneously and easily generated. By increasing the number of relatively inexpensive optical elements, an expensive LD
Since the system can be reduced, the economic effect is extremely large.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an LD-pumped solid-state laser device for simultaneously generating blue light and green light according to the present invention is applied will be described. An LD (semiconductor laser) 11 has a wavelength of 808 nm.
The applicant of the present application has proposed and proposed a method in which a condensing optical unit 13 is suitable for converting a non-circular laser beam into a circular small-diameter spot using an LD bar having a 20 W output. The solid-state laser system 10B for blue light and the solid-state laser system 10C for green light are simultaneously excited by an LD excitation system using a laminated glass beam shaper disclosed in 186246 to generate blue light and green light.

The first solid-state laser crystal 15 made of Nd: YAG is irradiated with 16 W of the excitation light 14 having a wavelength of 808 nm, and when the thickness of Nd: YAG is 2 mm, 70% (16%) is obtained.
W × 0.7 ≒ 11 W), and the remaining 30%, ie, 5 W, of the excitation light 14 leaked from the Nd: YAG is converted to Nd: Nd: Y.
The light is incident on the second solid-state laser crystal 23 composed of VO ₄ and is output from the solid-state laser system 10B as a blue light output having a wavelength of 473 nm of 1.1 W (16 W × 7% efficiency ≒ 1.1 W).
From the solid-state laser system 10C, 1W (5W × 20% efficiency 効率 1W) can be extracted as green light output of 532 nm.

[Brief description of the drawings]

FIG. 1 shows a block diagram of a conventional LD-pumped solid-state laser device that simultaneously generates blue light and green light.

FIG. 2 shows a block diagram of an LD-pumped solid-state laser device that simultaneously generates blue light and green light according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 LD-pumped solid-state laser device 10A LD-pumped system 10B Solid-state laser system for blue light 10C Solid-state laser system for green light 11 LD (semiconductor laser) 12 Semiconductor laser light 13 Focusing optical unit 14 Pump light 15 First solid-state laser Crystal 16, 17, 21 Reflecting surface 18, 25 Dichroic mirror 19, 27 Nonlinear optical crystal 20, 28 Reflecting mirror for resonance 22 Condensing lens 23 Second solid-state laser crystal 24, 26, 29 Reflecting surface

Claims (3)

[Claims] 1. A blue-light solid-state laser system is excited by excitation light from a common LD (semiconductor laser) system to extract blue light, and transmitted without being absorbed by the blue-light solid-state laser system. An LD-excited solid-state laser device that simultaneously emits blue light and green light by exciting a solid-state laser system for green light with excitation light and extracting green light at the same time. 2. The device according to claim 1, wherein the solid-state laser system for blue light absorbs 60 to 80% and transmits 20 to 40% of the excitation light from the LD (semiconductor laser) system. An LD-pumped solid-state laser device that simultaneously generates blue light and green light. 3. A solid-state laser crystal used for a blue-light solid-state laser system as a means for transmitting a part of the excitation light from the LD (semiconductor laser) system. 3. The LD-pumped solid-state laser device according to claim 2, wherein blue light and green light are simultaneously generated.