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WO1997009759A1 - Procede et dispositif laser d'amplification de la puissance de lasers a frequence doublee - Google Patents

Procede et dispositif laser d'amplification de la puissance de lasers a frequence doublee Download PDF

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Publication number
WO1997009759A1
WO1997009759A1 PCT/EP1996/003767 EP9603767W WO9709759A1 WO 1997009759 A1 WO1997009759 A1 WO 1997009759A1 EP 9603767 W EP9603767 W EP 9603767W WO 9709759 A1 WO9709759 A1 WO 9709759A1
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Prior art keywords
laser
arrangement according
laser arrangement
harmonic
oscillators
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Ceased
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PCT/EP1996/003767
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German (de)
English (en)
Inventor
Keming Du
Peter Loosen
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Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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Priority claimed from DE19536880A external-priority patent/DE19536880B4/de
Application filed by Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of WO1997009759A1 publication Critical patent/WO1997009759A1/fr
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
    • H01S3/108—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering
    • H01S3/109—Frequency multiplication, e.g. harmonic generation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
    • H01S3/2383—Parallel arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/0602—Crystal lasers or glass lasers
    • H01S3/0604—Crystal lasers or glass lasers in the form of a plate or disc
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/0619—Coatings, e.g. AR, HR, passivation layer
    • H01S3/0621—Coatings on the end-faces, e.g. input/output surfaces of the laser light
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/0627—Construction or shape of active medium the resonator being monolithic, e.g. microlaser
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/08059—Constructional details of the reflector, e.g. shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/08095—Zig-zag travelling beam through the active medium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H01S3/0813—Configuration of resonator
    • H01S3/0816—Configuration of resonator having 4 reflectors, e.g. Z-shaped resonators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H01S3/083—Ring lasers

Definitions

  • the present invention relates to a laser arrangement with at least two individual laser oscillators, the laser radiation of the oscillators being bundled by means of optical components. Furthermore, the invention relates to a method for power scaling of frequency-doubled lasers.
  • ERSA ⁇ ZBLA ⁇ T (RULE 26) radial dimensions which, in order to achieve a high beam quality, have to be in relation so that the Fresnell number of the oscillator does not become significantly greater than 1. If these boundary conditions are not met, the beam quality of high-power lasers is significantly impaired.
  • Another measure to scale the laser beam power is the use of oscillator amplifiers. These amplifiers are used to amplify the radiation from a laser oscillator with low power and high beam quality to a high power. However, this procedure has its limits, in particular in connection with continuously operated lasers.
  • laser arrays or field arrangements are set up. In such arrays, several laser oscillators are arranged side by side and operated in parallel.
  • the power of the individual laser oscillators adds up to a total laser power of such a laser array.
  • a problem associated with such a laser array is the coherent coupling of the oscillators to one another. In order to bundle the beams of the individual beam sources of the array in a common focusing point, corresponding optical measures for beam guidance must be taken. Furthermore, imaging errors lead to losses when the radiation of the laser oscillators freely propagates, which in turn has an effect due to a low efficiency. In addition, in order to convert the frequency of the laser oscillators and thus to adapt them to the specific fields of application and the specifications, additional measures must be taken which complicate the above-described problem of power scaling of laser arrangements.
  • the present invention is based on the object of specifying a laser arrangement and a method with which the power of at least two individual laser oscillators can be scaled and the frequency can be changed, specifically with a simple optical structure while achieving a high beam quality.
  • REPLACEMENT BLA ⁇ (RULE 26) Starting from a laser arrangement with at least two individual oscillators, this object is achieved in that the fundamental radiation of the respective oscillator is doubled in frequency by a nonlinear crystal and in that the respective radiation is coaxially superimposed by means of an optical, dichroic component is merged. According to the method, a power scaling of frequency-doubling lasers is carried out in that at least two laser oscillators are arranged next to one another and their fundamental wave is doubled in frequency and in that the doubled radiation is brought together coaxially.
  • the power can be scaled as desired to higher powers by adding further components in the form of individual laser oscillators to the system. This also applies in particular to continuously operated lasers.
  • the dichroic component is designed such that it also takes over the function of the frequency-doubling crystal.
  • the laser oscillators are assigned a common, non-linear crystal into which the fundamental radiation of the respective oscillators is radiated.
  • a nonlinear crystal which has two parallel surfaces, which are the entrance, exit and / or reflection surfaces for the Form radiation. With such a crystal, the same offsets of the respective neighboring beams are achieved in relation to one another to bring the radiation together, so that a simple geometry results.
  • the individual laser oscillators can be set up as ring resonators. Furthermore, there is the possibility of positioning or dividing the active media in the individual folding sections of the laser oscillators, on the other hand there is the possibility of incorporating the nonlinear crystal and the dichroic component into the individual folding sections.
  • a further, preferred structure can be achieved if the crystal in the ring resonators is assigned a function which deflects the radiation.
  • the crystal should have an entrance surface and a reflection surface, the entrance surface for the fundamental wave ( ⁇ ) being coated with an anti-reflective coating and for the second harmonic (2 ⁇ ) being coated with a highly reflective surface, and the reflection surface for the fundamental wave ( ⁇ ) and the second harmonic (2 ⁇ ) is highly reflective.
  • a coupling-out surface for the second harmonic (2 ⁇ ) is provided within the entrance surface or the reflection surface of the non-linear crystal in order to couple this radiation component out of the non-linear crystal after combining all the individual oscillators as an output beam.
  • the structure of the laser arrangement as stated above is preferred in particular with respect to solid-state lasers, moreover for solid-state lasers which are longitudinally pumped by means of diode laser radiation.
  • solid-state lasers there is the possibility of the individual To separate the solid media of the individual laser oscillators;
  • an embodiment is preferred in which a common solid medium is assigned to the laser oscillators, so that a minimum volume for the active medium is used for such a laser arrangement consisting of solid state lasers.
  • the solid-state medium can be formed as an etaon, one surface having an antireflective coating for the fundamental ( ⁇ ) and the other surface having a highly reflective coating for the fundamental (co).
  • the respective resonator radiation is brought together in the solid body medium, embodied as an etalon, the highly reflective coating for the fundamental wave ( ⁇ ) of the solid body medium being used in this arrangement at the same time in the context of a ring resonator as a strain element.
  • While preferred structures of the laser arrangement in the form of ring resonators are specified, based on the principle according to the invention, it is also possible to construct a laser arrangement with laser oscillators arranged parallel to one another.
  • the laser arrangement in the form of individual ring resonators, combining the respective radiation of the individual oscillators by means of an optical, dichroic component in such a way that they are coaxially superimposed, is always preferred when stability and monomode operation are required.
  • the construction of the laser arrangement in such a way that the laser oscillators each form a linear resonator, the radiation of which is brought together coaxially overlapping by means of an optical, dichroic component Doubling the fundamental radiation of the respective oscillator by means of a non-linear crystal is to be preferred if a flexible design of the laser arrangement and effective cooling have priority.
  • a preferred embodiment with regard to the linear structure is obtained if the nonlinear crystal, which doubles the fundamental radiation of each oscillator, has a first surface and an opposite second surface, both of which are coated with an anti-reflective coating for the fundamental wave and for second harmonics (2co ) are highly reflective coated, so that the basic radiation ( ⁇ ) can enter this from both outer surfaces of the nonlinear crystal, while the second harmonic (2co) within the crystal by reflections and to a corresponding coupling-out area, which is for the second Harmonic (2co) is designed to be anti-reflective, is led to decouple the second harmonic (2 ⁇ ) from the non-linear crystal.
  • the linear crystal is arranged in the beam path of the individual laser oscillators at an angle of incidence of the radiation in such a way that the radiation components are refracted within the crystal and guided in such a way that the doubled radiation (second harmonic (2 ⁇ )) the individual laser oscillators are added together and masked out as combined total radiation (2co) from the nonlinear doubling crystal.
  • the distances of the radiation from neighboring oscillators on the input side of the dichroic components can be relatively large.
  • an optical arrangement is advantageous which is inserted into the beam path on the input side of the dichroic components. With this optical arrangement, the distance of the beams of the individual laser oscillators is approximated in the desired manner, preferably via reflection surfaces.
  • step-like mirror elements are advantageous which deflect the beam at least once and thus bring the beams closer together.
  • one cannot with such stair-step-like elements by suitable inclination of the reflection surfaces given parallelism of the radiation of the individual laser oscillators can be achieved.
  • FIG. 1 shows a first embodiment of a laser arrangement according to the invention with three individual laser oscillators with a ring resonator using an etalon for merging or coaxial superimposition of the second harmonic,
  • FIG. 2 shows a laser arrangement according to a second embodiment, similar to FIG. 1, the etalon simultaneously taking on the function of a doubler crystal
  • FIG. 3 shows a third embodiment with an additional etano compared to FIG. 2, which is pumped by means of a diode laser and acts as an active medium,
  • FIG. 4 shows a fourth embodiment, modified from FIG. 3, in which a prismatic, active medium is used instead of the etalon-shaped, active medium of FIG. 3,
  • FIG. 5 shows a fifth embodiment with a square prism as the laser medium
  • FIGS. 6 and 7 show a seventh embodiment of a laser arrangement, which by way of example shows two linear resonators with an ethalon-shaped doubler, embodiment 7 having two additional ⁇ / 4 plates on both sides of the active medium compared to the embodiment in FIG. 6,
  • FIG. 8 shows a further, linear resonator in which the doubler crystal, as shown in FIGS. 6 and 7, is divided into individual segments, the segments being offset from one another
  • FIG. 9 shows a single segment of the doubler of FIG. 8, the outlet surface being curved
  • Figure 10 schematically shows a structure of a linear oscillator with an optical arrangement for the radiation distance approximation of two adjacent laser oscillators.
  • FIG. 1 shows an arrangement of three individual laser oscillators 1 with an active medium 2, which are pumped longitudinally by means of diode laser radiation 3, indicated by arrows.
  • the active media are preferably solid bodies which, as indicated in FIG. 1, can be combined to form a common solid body.
  • the individual laser oscillators 1 have a ring resonator with three deflecting mirrors 4, 5 and 6 and a first surface 7 of an etaion 8, which serves as a dichroic component for axially superimposing the radiation from the individual laser oscillators 1.
  • the deflection mirrors 4, 5 and 6 are coated in a highly transparent manner for the fundamental wave ( ⁇ ) and for the second harmonic (2co).
  • the deflecting mirror 4 for the pump radiation (fundamental wave ( ⁇ )) is highly transparent or antireflective.
  • the etalon 8 has a highly reflective coating on its first surface 7 for the fundamental wave ( ⁇ ), while the coating on the first surface 7 is highly transparent for the second harmonic (2co).
  • the opposite, second surface 9 of the etalon, parallel to the first surface 7, is provided with a highly reflective coating for the second harmonic.
  • the fundamental waves emitted by the laser media, excited by the diode laser pump radiation are frequency-doubled within the resonator (second harmonic 2 ⁇ ) by means of a non-linear doubler crystal 10, which is inserted between the deflecting mirror 6 and the etalon 8 in the beam path.
  • a 1 in the doubler crystal passes at point a 4 on the output side of the doubler crystal 10 via the first surface 7, for the second harmonic ( 2 ⁇ ) coated with an anti-reflective coating, enters the etalon 8 and follows the path s ⁇ -b ⁇ exits the first surface 7 of the etalon 8 and takes the further path b ⁇ -b j -b.
  • the second harmonics (2co) generated in the various ring oscillators are brought together by means of the etalon and decoupled in such a way that the second harmonics (2 ⁇ ) coaxially overlap, so that a frequency-doubled output beam 12 is generated, the power of which derives from the individual power of the three ring oscillators additively composed.
  • the power in relation to the second harmonic (2 ⁇ ) of this laser arrangement can be scaled in a simple manner by the number of ring oscillators. In order to increase the performance, further ring oscillators are added to the arrangement.
  • the reference to surfaces means “HRco” highly reflective for the fundamental wave ( ⁇ ), “HR2 ⁇ ” highly reflective for the second harmonic (2 ⁇ ) and “HTco” highly transmissive or antireflective for the fundamental wave ( ⁇ ) and “HT ⁇ p” highly transmissive for the pump radiation ( ⁇ ).
  • a Faraday rotator 13 for unidirectional operation is in the ring oscillators between the deflecting mirrors 5 and 6 inserted.
  • the laser arrangement of the first embodiment, as shown in FIG. 1, can be simplified in that the etalon denoted by reference number 19 in FIG. 2 consists of a nonlinear material and thus, in addition to bringing the radiation of the individual laser oscillators 1 together serves to double the fundamental radiation ( ⁇ ) (2 ⁇ ).
  • the second harmonic (2 ⁇ ) is generated within the doubler 19 designed as an etalon.
  • the second harmonic (2co) generated within the oscillator a r ..a 4 ...
  • a 1 is guided within the etalon 19 by multiple oscillation to the decoupling point d, which in the second exemplary embodiment shown in FIG Area of the second surface 8 is provided by this surface area 14 for the second harmonic (2 ⁇ ) is coated with an anti-reflective coating.
  • the power of this output beam 12 is thus additively composed of the individual powers of the laser oscillators 3.
  • the second harmonic (2co) does not pass through the active laser medium 2. For this reason, the deflecting mirrors 4, 5 and 6 only have to be highly reflectively coated for the fundamental wave ( ⁇ ) his.
  • FIG. 2 Insofar as components are designated in FIG. 2 with the corresponding reference numerals and reference signs, which are also used in the first embodiment in FIG. 1, the corresponding statements made with reference to FIG. 1 can be applied to the second embodiment in FIG. 2 be transferred. The same applies to the embodiments explained below with reference to FIGS. 3 to 9.
  • REPLACEMENT SHEET (REGa 26) Etalon 19 the etalon 22 and the deflecting mirrors 5 and 6 fix the resonator.
  • the further etalon 22, which is also the active medium, is emitted by means of diode laser radiation 3 via its outer surface 17, which is (co) highly reflective for the fundamental wave. pumped. Due to the pump radiation, there are three adjacent ring oscillators with the curves shown.
  • the second harmonic (2co) is generated inside the resonator and within the doubler stage 19 and is led to the decoupling point d (surface area 14). Both the doubler etalon 19 and the solid-state etalon 22 each bring the rays together. As shown in FIG. 3, the second harmonic (2 ⁇ ) up to the decoupling point d only remains within the doubler stage 19.
  • the structure according to the third embodiment, which is shown in FIG. 3 has the advantage that, for example only a solid medium is required.
  • FIG. 4 A fourth embodiment is shown in FIG. 4, which can be regarded as a modification of the third embodiment according to FIG. 3.
  • a laser prism 32 is used as the active medium, which in turn is pumped from the outside by means of three diode lasers, indicated by the radiation arrows 3.
  • a further radiation guiding prism 34 which is transparent to the fundamental radiation ( ⁇ ), is assigned to the base surface 33 of the laser prism 32, the surface on the right in FIG. 4 of which is assigned a doubler etalon 19, comparable to the doubler etalon of FIG. 3.
  • Both the base surface 33 of the laser prism 32 and the base surface 35 of the radiation guide prism 34 are designed to be (co) antireflective for the fundamental radiation, within the active medium 32 and the radiation guide prism 34, three ring oscillators arise, excited by the diode laser radiation 3 1.
  • the fundamental wave (co) is passed through on the inner, first surface 7 of the doubler stage 19, which is doubled (second harmonic (2 ⁇ )), due to the highly reflective coating of the first surface 7 and of the second surface 8 of the etalon 19 the second harmonic (2 ⁇ ) to that which is transparent for the second harmonic Area 14 is guided.
  • This construction has the particular advantage that the extremely high reflectivity of the total internal reflection can be used.
  • FIG. 5 A fifth embodiment is shown in FIG. 5, in which the active laser medium is formed in the form of a square prism 42.
  • the active medium 42 is excited by the radiation 3 from three diode lasers, so that three adjacent oscillators (fundamental wave (co)) with linear ring resonators are created.
  • Three of the surfaces of the square prism 42 are highly reflective for the fundamental (co), while the lower right end face in FIG. 5, comparable to the corresponding end face of the radiation guiding prism 34 in FIG. 4, is coated with an anti-reflective coating for the fundamental wave (co).
  • This end face is assigned a doubler etalon 19, the first face 7 of which is coated with an anti-reflective coating for the fundamental wave ( ⁇ ), while for the second harmonic (2 ⁇ ), like the opposite, parallel second face 9, it is coated with a highly reflective coating .
  • the second harmonic (2co) is in turn coupled out at the surface area 14, so that an output beam 12 is formed, the power of which is composed of the power of the three individual laser oscillators 1.
  • Essentially only two components are required for this arrangement, in addition to the diode laser for optical pumping, in the form of the active medium 42 (Lase ⁇ risma) and the doubler etaion 19.
  • further oscillators can be generated by means of further diode pump lasers, the radiation of which is added to the radiation of the three laser oscillators 1 shown in FIG. 5 by means of the doubler stage 19.
  • FIGS. 1 to 5 show five embodiments with ring oscillators
  • FIGS. 6, 7 and 8 show structures of various linear oscillators in which the structure according to the invention is implemented.
  • the linear resonators as shown in FIGS. 6, 7 and 8, have two resonator end mirrors 44, between which an active medium 52 is arranged. Furthermore, a doubler etalon 48 is positioned in the beam path between the active medium 52 and the right-hand resonator end mirror 44.
  • the left resonator end mirror 44 which is highly reflective for the fundamental wave (co), is used to pump by means of pump beams, which in turn are diode laser radiation 3.
  • the active medium excited by means of the spot radiation 3 emits three basic periods ( ⁇ ), so that three linear oscillators 11 stand side by side between the resonator end mirrors 44, in the doubler etalon 48, which has its first surface 7 and its second surface 9 under one is positioned at a suitable angle to the fundamental radiation (co), the second harmonic (2co) is generated in the two propagation directions, indicated by the respective double arrows within the etalon 48.
  • the doubler etalon 48 is designed such that the second harmonic (2co) generated by the fundamental wave (co) running on the left is reflected in the other direction of propagation, so that in FIG.
  • the power of the output beam 12 is additively composed of the powers of the three linear individual resonators 21.
  • the second harmonic (2 ⁇ ) is generated in two directions within the doubler ettaion 48, it is advantageous to chamfer the lower end face 49 of the etalon 48 and to orient it to the first and second surfaces 7, 9 in such a way that the second harmonic (2 ⁇ ), which is reflected towards this surface, is reflected back with only one reflection in order to lead it to the coupling-out surface area 14. In this way the reflections and thus the reflection losses in this area of the etalon 48 can be kept low.
  • the power of the laser arrangement i.e. the power of the output beam 12, which is doubled in frequency, can be scaled upwards.
  • the seventh embodiment shows the basic structure as described with reference to FIG. 6.
  • a ⁇ / 4 plate 45 is inserted on both sides of the active medium 52. Through these ⁇ / 4 plates 45, the polarizations of the fundamental waves (co) running to the left and to the right are placed in such a way that the polarizations of these opposing fundamental waves (co) running to the left and right are perpendicular to one another. If the etalon-shaped doubler 48 is now phase-adjusted and intended for the clockwise wave, then the phase-matching condition for the counter-clockwise wave is not met.
  • a second harmonic (2co) is generated only by the clockwise fundamental wave (co), but not for the counterclockwise fundamental wave (co), as is shown by the arrows running in one direction within the doubler stage 48 of FIG. 7 is indicated, generated.
  • the second harmonic (2co) generated by the individual laser oscillators 21 is coated by means of the etalon 48, the first surface 7 and second surface 9 of which are in turn coated for the fundamental ( ⁇ ) antireflectively, but highly reflective for the second harmonic (2co) ⁇ brought together and an output beam 12 (2 ⁇ ) coupled out over the surface area 14.
  • This embodiment with the so-called "twisted mode” also leads to the avoidance of spatial, so-called “hole-burning", which increases the performance stability.
  • each linear oscillator 21 is assigned a respective doubler crystal 50.
  • Each of these doubler crystals 50 in turn has a first surface 7 and a second surface 8, which are each antireflectively coated for the fundamental radiation, and highly reflective for the second harmonic (2 ⁇ ).
  • the second harmonics (2co) generated in the doubler crystals 50 are shaped and reflected on the second surface 9 to the adjacent doubler crystal 50, where they emerge from the lateral end surface 53 which is coated for the second harmonic (2co) with an anti-reflective coating, emerge and enter the corresponding lateral end face 54 of the adjacent doubler crystal part 50, which is also coated with an anti-reflective coating for the second harmonic, strike the corresponding first face 7, are reflected from there to the second face 9 and are reflected by there in turn are directed to the end face 53, exit there and enter the next doubler crystal 50 in each case.
  • the output beam 12 is then coupled out via the end face 53.
  • This embodiment has the advantage that precisely when an active medium 52 is assigned to each laser oscillator, as shown in FIG. 8, so that the individual linear resonators 21 are spaced apart from one another more than, for example, in the embodiment of the figure 7 is the case, by means of the individual doubler crystals 50, a larger offset to one another can be generated in order to additively bring together the radiation component in the form of the second harmonic (2 ⁇ ) of the respective linear oscillators 21.
  • FIG. 9 shows a single doubler crystal 50, as used in the arrangement in FIG. 8, the outlet-side end face 53 being arched, in contrast to the illustration in FIG. 8.
  • Such a measure can be advantageous not only at the exit surface 53 but also at the respective entry surfaces 54 in order to match the caustics of the second harmonics (2 ⁇ ) generated in the respective laser oscillators 21 to one another.
  • the use of the doubler crystals 50 assigned to each linear oscillator 21 can be used in an analogous manner in the ring oscillators shown and described in the embodiments of FIGS. 1 to 6.
  • the measures according to the invention offer the advantages of a low thermal load on the optical components and the simple and virtually unlimited scalability of the laser arrangements in relation to frequency-doubled radiation. Due to mechanical structures that are required for the individual laser oscillators 1 or the field arrangement, the distances can be very large, as is shown schematically in FIG. 10 with the distance "D".
  • an optical arrangement 60 which is composed of a first deflection element 61 and a second deflection element 61, which each have stair-shaped mirror surfaces 63 which are stepped or are arranged at different distances from the laser oscillators 1 such that the distance between the two beams, denoted by "d", approximates on the output side of the second deflecting element 62 becomes.
  • the double deflection can be designed such that the same resonator lengths of the individual laser resonators are achieved with simultaneous approach (or distance).

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Lasers (AREA)

Abstract

Ce dispositif laser comprend au moins deux oscillateurs laser (2) individuels dont le rayonnement est focalisé en un faisceau par des composants optiques. Le dispositif se caractérise en ce que la fréquence des ondes fondamentales du rayonnement émis par chaque oscillateur est doublée par un cristal (10) non linéaire et en ce que le rayonnement des deux oscillateurs est réuni en un faisceau de rayonnements coaxiaux superposés au moyen d'un composant optique dichroïque (par exemple un étalon (9)). L'invention concerne également le procédé d'amplification de puissance correspondant à ce dispositif. Le cristal non linéaire et le composant dichroïque peuvent être combinés en un seul élément.
PCT/EP1996/003767 1995-09-01 1996-08-27 Procede et dispositif laser d'amplification de la puissance de lasers a frequence doublee Ceased WO1997009759A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19532335 1995-09-01
DE19532335.1 1995-09-01
DE19536880A DE19536880B4 (de) 1995-09-01 1995-10-04 Laseranordnung zur Skalierung von frequenzverdoppelten Lasern
DE19536880.0 1995-10-04

Publications (1)

Publication Number Publication Date
WO1997009759A1 true WO1997009759A1 (fr) 1997-03-13

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PCT/EP1996/003767 Ceased WO1997009759A1 (fr) 1995-09-01 1996-08-27 Procede et dispositif laser d'amplification de la puissance de lasers a frequence doublee

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WO (1) WO1997009759A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7860144B2 (en) 2004-07-30 2010-12-28 Osram Opto Semiconductors Gmbh Semiconductor laser component, optical device for a semiconductor laser component, and method for producing an optical device
CN116724470A (zh) * 2021-08-24 2023-09-08 维林光电有限公司 使用分层非线性光学器件的腔内谐波产生

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4823357A (en) * 1986-11-10 1989-04-18 The United States Of America As Represented By The Secretary Of The Air Force Diffraction limited dichroic combiner diode laser
DE3829812A1 (de) * 1988-09-02 1990-03-15 Fraunhofer Ges Forschung Festkoerperlaser
WO1990009688A1 (fr) * 1989-02-09 1990-08-23 Massachusetts Institute Of Technology Laser a micropuces
US4978197A (en) * 1988-08-26 1990-12-18 Fuji Photo Film Co., Ltd. Beam-combining laser beam source device
JPH06208152A (ja) * 1993-01-08 1994-07-26 Oki Electric Ind Co Ltd 光第２高調波発生装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4823357A (en) * 1986-11-10 1989-04-18 The United States Of America As Represented By The Secretary Of The Air Force Diffraction limited dichroic combiner diode laser
US4978197A (en) * 1988-08-26 1990-12-18 Fuji Photo Film Co., Ltd. Beam-combining laser beam source device
DE3829812A1 (de) * 1988-09-02 1990-03-15 Fraunhofer Ges Forschung Festkoerperlaser
WO1990009688A1 (fr) * 1989-02-09 1990-08-23 Massachusetts Institute Of Technology Laser a micropuces
JPH06208152A (ja) * 1993-01-08 1994-07-26 Oki Electric Ind Co Ltd 光第２高調波発生装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 018, no. 567 (P - 1820) 28 October 1994 (1994-10-28) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7860144B2 (en) 2004-07-30 2010-12-28 Osram Opto Semiconductors Gmbh Semiconductor laser component, optical device for a semiconductor laser component, and method for producing an optical device
CN116724470A (zh) * 2021-08-24 2023-09-08 维林光电有限公司 使用分层非线性光学器件的腔内谐波产生
US20230335969A1 (en) * 2021-08-24 2023-10-19 Pavilion Integration Corporation Intracavity harmonic generation with layered nonlinear optic

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