KR100274416B1 - Laser light beam generator - Google Patents

Abstract

The laser light beam generator includes a laser diode, a laser medium, a nonlinear photonic crystal element, a reflection mirror, a deflection mirror, a temperature control device and a case. The laser diode emits at least one pumping laser light beam. The laser medium is excited by the pumping laser light beam from the laser diode. The nonlinear photonic crystal element is disposed in the output optical path of the pumping laser light beam from the laser diode. The reflecting mirror constitutes a resonator having a laser medium and a nonlinear photonic crystal element. The deflection mirror deflects the optical path of the light beam from the resonator. The temperature control device controls the temperature of the laser diode and the resonator. The case contains a laser diode, a laser medium, a nonlinear photonic crystal element, a reflection mirror, a deflection mirror, and a temperature control device.

Description

Laser light beam generator

1 is a side cross-sectional view showing a schematic configuration of a first embodiment of a laser light beam generating apparatus according to the present invention.

2 is a schematic plan view of a state in which the lid is removed from the laser light beam generator of the present invention.

Figure 3 is a perspective view of one embodiment of a resonator mounting block of the present invention.

4 is a schematic configuration diagram of a second embodiment of a laser light beam generating apparatus according to the present invention;

5 is a graph showing the absorption coefficient of the laser medium Nd: YAG.

6 is a graph showing the wavelength distribution of the relative light intensity of a laser light beam emitted from a laser diode.

7 is a graph showing the temperature characteristics of the actual absorption coefficient of the pumped light beam from the laser diode to Nd: YAG.

8 is a graph showing temperature characteristics of laser light beam power and noise level.

* Explanation of symbols for main parts of the drawings

11 laser device 13 lens

15: 1/4 wave plate 16, 19: reflecting surface

17 laser medium 18 nonlinear photonic crystal device

20: resonator 21: resonator mounting block

22: deflection mirror 23: base

24: temperature control device 25: thermistor

31: Case 32: Bottom

34: ejection opening

The present invention relates to a laser light beam generator, and more particularly, to a laser light beam generator for generating a laser light beam wavelength converted by a nonlinear photonic crystal device.

For example, Japanese Patent Application Laid-Open No. 48-93784 discloses a laser light beam generator using actual wavelength conversion such as second harmonic generation (SHG). The laser beam generator generates a short wavelength laser beam or a converted wavelength laser beam by a nonlinear photonic crystal device, and uses a laser light beam of a fundamental frequency having a high power density in the laser resonator.

A conventional laser light beam generator using actual wavelength conversion includes a light beam source, a resonator having a laser medium and a nonlinear optical device element. At least one pumping light beam emitted from the light beam source is emitted to the laser medium of the resonator. The laser medium is excited by the pumping light beam to generate a laser light beam of a fundamental frequency. The laser light beam of the fundamental frequency generated in the laser medium is emitted to the nonlinear optical device element. As a result, the SHG laser light beam is generated in the nonlinear photonic crystal device and output from the resonator.

In order to assemble and use the laser light beam generator using the actual wavelength conversion in various devices such as an optical disc recording and / or reproducing apparatus, the optical elements necessary for SHG laser light beam emission are included in a small case so as to be easy to handle with the components. It is preferable.

In general, in order to stably obtain an SHG laser light beam having high efficiency in the above-described laser light beam generator, the pumping light beam from a light beam source such as a laser diode needs to be effectively absorbed by a laser medium such as Nd: YAG.

In addition, temperature control within a limited range is required for stable operation with low noise due to reasons such as the change in the longitudinal mode and the phase delay amount of the nonlinear photonic crystal device of the resonator. In order for the pumping light beam to be effectively absorbed by the laser medium, the wavelength of the laser medium needs to be adjusted, and the light beam source needs to be temperature controlled due to the change in temperature of the light beam source such as the laser diode of the pumping light beam. Therefore, because the temperature control of the resonator and the light beam source is necessary, the temperature control of the two systems and the temperature detection of the two systems are required, and the configuration of the structure accordingly causes a problem of increased power consumption. In particular, in a laser light beam generating apparatus including a laser light beam radiation embedded in a small size case and an optical element for a temperature control device, when the light beam source is disposed in each temperature control device, the position control between the light beam source and the resonator is controlled. This becomes difficult, causing unstable operation problems due to relative position changes with temperature changes.

On the other hand, a laser light beam generator using an actual wavelength conversion, equipped with a SHG laser light beam radiation light system embedded in a small case, is so-called optical that is preferably operated without great difficulty when assembled in various devices such as an optical disc recording and / or reproducing apparatus. Axis matching needs to be performed. Optical axis matching is performed in two vertical directions in the plane perpendicular to the optical axis. However, the optical system device for generating the SHG laser light beam is provided in the optical axis direction parallel to the bottom surface of the case which is horizontal in the direction parallel to the bottom surface of the case which is a horizontal plane.

Since the bottom surface as the horizontal surface is usually the installation surface of the laser light beam generator, one of two vertical directions for optical axis matching is perpendicular to the installation surface.

Due to the vertical movement to the case mounting surface, it is difficult to install for fine adjustment operation and to improve the accuracy of the operation.

It is therefore an object of the present invention to provide a laser light beam generating apparatus which solves the above problems.

It is another object of the present invention to provide a laser light beam in which temperature control for high efficiency and stable laser light beam radiation is performed by small power consumption and a simple structure.

It is still another object of the present invention to provide a laser light beam generating apparatus in which various elements for generating a laser light beam are configured in a package, so that fine adjustment for optical axis matching can be easily performed to improve the accuracy of operation.

According to a first embodiment of the present invention, there is provided a laser light beam generator including a laser diode, a laser medium, a nonlinear photonic crystal device, a reflection mirror, and a temperature control device. The laser diode emits at least one pumping laser light beam. The laser medium is excited by the pumping laser light beam from the laser diode. The nonlinear photonic crystal element is provided in the output optical path of the pumping laser light beam from the laser diode. The reflective mirror constitutes a resonator with the laser medium and the nonlinear photonic crystal element. The temperature control device controls the temperature of the laser diode and the resonator.

According to a second embodiment of the present invention, there is provided a laser light beam generator including a laser diode, a laser medium, a nonlinear photonic crystal device, a reflection mirror, a deflection mirror, and the like. The laser diode emits at least one pumping laser light beam. The laser medium is excited by the pumping laser light beam from the laser diode. The nonlinear photonic crystal element is provided in the output optical path of the pumping laser light beam from the laser diode. The reflection mirror constitutes a resonator with a laser medium and a nonlinear photonic crystal device. The deflection mirror deflects the optical path of the light beam from the resonator.

The case contains a laser diode, a laser medium, a nonlinear photonic crystal element, a reflection mirror and a deflection mirror.

In the above invention, one temperature-controlled mesh is controlled by the light beam source and the resonator to generate a stable, high-efficiency laser light beam output, thereby reducing the size and power consumption of a simple structure and size.

In the above-described invention, since the laser light beam is taken out of the case by deflecting the optical axis of the resonator and the light beam source installed in the case, the laser light beam is radiated perpendicularly to the attaching surface of the case. Easy to fine tune.

The present invention will be described below with reference to the accompanying drawings.

In the drawings, the invention is described in detail as a preferred embodiment.

1 is a schematic sectional view showing a schematic configuration of a laser light beam generating apparatus according to a first embodiment of the present invention. 2 is a schematic top view of the lid removed from the apparatus shown in FIG.

The laser beam generating apparatus shown in FIGS. 1 and 2 is a semiconductor laser element 11, a lens 13, a quarter wave plate 15, reflecting surfaces 16, 17, a laser medium 17, a nonlinear The photonic crystal device 18, the deflection mirror 22, the base 23, the temperature control device 24, the thermistor 25 and the package or case 31. As the light beam source, a semiconductor laser element 11 such as a laser diode is provided on the fixed table 12. A lens 13 for converging a light beam such as a pumping light beam emitted from the semiconductor laser element 11 is provided in the lens mounting block 14. Reflecting surface 16, such as a dichroic mirror, has a wavelength selectivity for transmitting a pumped laser light beam having a wavelength of 810 nm, for example, and reflects a laser light beam of 1064 nm fundamental frequency generated in the laser medium 17. The reflective surface 16 is formed on the incident surface of the quarter wave plate 15 by coating. In the above embodiment, the reflecting surface 16 is in the form of a concave mirror if viewed from the side laser medium 17. The laser medium 17 is made of Nd: YAG and is a rod-shaped laser medium. The laser medium 17 may also be Nd: YV04, Nd: BEL or LNP. The nonlinear photonic crystal device is made of KTP (KTiOP04) and generates a second harmonic (SHG). The nonlinear photonic crystal device 18 may be, for example, BBO, LN or LBO. The reflecting surface 19, such as a dichroic mirror, has a wavelength selectivity for transmitting the laser light beam of the second harmonic wave of 532 nm generated by the nonlinear photonic crystal device 18 and reflecting the light beam of the fundamental frequency. The reflective surface 19 is formed on the rear surface of the nonlinear photonic crystal device 18. Thus, the resonator 20 is provided between the reflecting surface 16 of the quarter wave plate 15 and the reflecting surface 19 of the nonlinear photonic crystal device 18. In this laser light beam generator, the pumped laser light beam collected by the lens 13 is irradiated to the laser medium 17 via the incident surface of the quarter-wave plate 15. The laser medium 17 is excited by the pumping laser light beam to generate a laser light beam of a fundamental frequency. The laser light beam of the fundamental frequency is irradiated to the nonlinear photonic crystal device 18. As a result, the laser beam of the second harmonic wave of 532 nm is generated by the nonlinear photonic crystal device 18. The quarter wave plate 15 is a birefringent element used for the laser light source proposed by the applicant of US Patent No. 4,910,740 to stabilize the laser light beam of the second harmonic wave emitted as the output of the laser light beam. That is, the laser light beam of the fundamental frequency generated from the laser medium 17 passes through the nonlinear photonic crystal element 18 installed in the resonator 20 by resonant movement to generate the second harmonic laser light beam of type II. The polarization plane of the laser light beam is rotated by a birefringent element such as a quarter wave plate 15 inserted in the resonator 20 to set two vertically unique polarized light beams as the fundamental wavelength mode. The energy exchange between the two intrinsic polarization beams of the laser light beam of the fundamental frequency is not generated in the second harmonic generation process by the selection of the phase amount Δ and the azimuth angle θ of the quarter wave plate 15. As a result, the laser light beam of the fundamental frequency can be stabilized and the laser light beam of the second harmonic comes out. On the other hand, by integrating the quarter-wave plate 15, the laser medium 17, and the type II phase matched nonlinear photonic crystal device 18 in intimate contact with each other, the laser light beam generator can be miniaturized as a whole. Conversion efficiency is also improved.

The surfaces of the respective quarter wave plates 15 constituting the resonator 20, the laser medium 17, and the nonlinear photonic crystal device 18 are attached to each other in close contact with each other in a diagram with an antireflective coating. The resonator 27 is installed on the resonator mounting block 21. The mounting block 21 forms a V-shaped groove 21V as shown in FIG. The quarter wave plate 15, the laser medium 17, and the nonlinear photonic crystal device 18 are guided by the grooves 21V and are installed in the installation block 21. The nonlinear photonic crystal device 18 is provided such that the polarization direction of the back light beam of the second harmonic becomes the direction indicated by the arrow X or the double arrow S in FIG. 3 in the direction indicated by the arrow Z which is the optical axis.

If used, the KTP as the nonlinear photonic crystal device 18 only needs to be cut so that the XY piece includes the a and b axes of the crystal and the Y axis perpendicular thereto is the c axis of the crystal. This polarization direction is the S polarization direction of the deflection mirror 22.

The laser beam of the second harmonic wave emitted from the resonator 20 is deflected upward by the deflection mirror 22. The deflection angle of the deflection mirror 22 is 45 degrees.

The deflection mirror 22, the mounting block 21 for mounting the resonator 20, the mounting block 14 for mounting the lens 13, and the fixed table 12 for mounting the semiconductor laser element 11 have the same base. It is installed in 23. These elements are temperature controlled in their entirety by a temperature control device 24 such as a so-called thermoelectric (TE) cooler. The thermistor 25 for sensing the temperature of the upper surface area of the base 23 is installed in the fixed table 12.

Hereinafter, a temperature control device 24 such as a TE cooler will be described. In this first embodiment, the wavelength control of the semiconductor laser element 11 emitting the pumping light beam and the temperature control for stabilizing the resonator 20 are executed by one temperature control device or TE cooler 24. In the case where the pumping light beam is effectively absorbed by the laser medium 17 and the stable resonance temperature range exists in the resonator 20 and narrow, respectively, the semiconductor laser element 11 generating the wavelength is selected to select Nd: YAG. The absorption of the laser medium 17 needs to exceed a predetermined value within the temperature range for the stable region of the resonator 20. You can also choose a resonator instead.

In order to enlarge the temperature range in which the resonator 20 is stable, it is effective to shorten the length of the birefringent crystal whose phase delay amount depends on the temperature or to use a crystal having a low temperature dependency. Temperature control consists of the following operations. That is, the thermistor 25 or temperature sensing device senses the temperature on the base 23, in particular the temperature of the nonlinear photonic crystal device 18 and the semiconductor laser element 11 in the resonator 20. According to the temperature sensed by the thermistor 25, the temperature control device or TE cooler 24 controls heat and heat absorption to achieve a predetermined target temperature.

Thus, one temperature control device 24 performs temperature control to stabilize the resonator 20 by adjusting the wavelength of the semiconductor laser element 11 to an absorption wavelength, and there is no need to install a temperature control device separately for each part. Since there are two or more temperature controllers, it is possible to completely overcome the structural complexity and difficulties in the arrangement of the temperature controllers. Thus, the number and cost of many component parts can be reduced, the control unit including the circuit can be simplified, and the size and power consumption can be reduced.

The device for laser light emission is embedded in a package or case 31. As shown in FIG. 2, the package or case 31 is a bottom surface, which is an attachment surface fixed to the mounting flange 30 by a fixing screw for screwing into the tab hole 37 formed in the mounting flange 30, or the like. 32). The devices 11, 13, 15, 17, 18 are arranged in a direction parallel to the bottom surface 32 as a plane. If the laser beam is taken out of the case 31 as a horizontal plane in a direction parallel to the bottom surface 32, it is necessary to move in both the vertical and horizontal directions for optical axial matching, so that the vertical movement of the laser beam The structure is complicated. In order to avoid this, the laser light beam emitted from the resonator 20 is deflected by the deflection mirror 22 having a 45 degree inclination angle in a direction perpendicular to the bottom surface 32 and is formed on the lid 33 of the case 31. Exit through the opening 34. The opening 34 is closed by the transparent plate 35.

The deflection of the deflection mirror 22 having a 45 degree inclination angle can be easily increased for the S-polarized beam. However, it cannot be increased for P polarized beams. Above all, if the incident light beam is composed of a mixture of the S-polarized beam element and the P-polarized beam element, the reflected light beam becomes an elliptical polarized beam, which is difficult to control. This is because the reflection of the S-polarized beam and the reflection of the P-polarized beam are different. Therefore, in this embodiment, the azimuth angle of the nonlinear photonic crystal device 18, such as KTP, is determined by cutting the crystal, so that its outer surface is determined and the polarization direction of the SHG laser light beam emitted from the nonlinear photonic crystal device 18 is deflected. Coincides with the S polarization direction.

In this case, the S-polarized light reflection is applied to the surface of the deflection mirror 22 to raise it to 99.9%, for example, to reduce power loss to the lowest possible. The SHG laser light beam is taken out vertically through the extraction opening 34 to the lid 33 of the case 31.

In the compact compact SHG laser light beam generator shown in FIGS. 1 and 2, the size of the bottom surface of the case 31 including the flange 36 is 38 mm x 28 mm and the height of the case is equally about 16 mm. In this case 31, the semiconductor laser element 11, the resonator 20 mainly consisting of the laser medium 17 and the nonlinear photonic crystal device 18, the lens 13, and the temperature control device 24 are in place. Is installed on. Thus, the SHG laser light beam is emitted by simply applying electric power from the outside of the laser generator. The SHG laser emitter has a shorter length than the vibration wavelength of a conventional semiconductor laser device at ambient temperature, and thus, a stable short wavelength laser light beam is preferably obtained by applying a current thereto as in the semiconductor laser device.

In the laser light beam generator as the SHG laser light beam generator, the polarization direction of the nonlinear photonic crystal device 18 coincides with the S polarization direction of the deflection mirror 22, thereby enhancing the reflection of the deflection mirror 22 with respect to the S polarization beam. Can be. After the reflection, the SHG laser light beam emitted from the extraction opening 34 has a constant polarization direction and is not polarized in an ellipse. Since the polarization direction of the extraction light beam is determined in relation to the case, it can be easily configured in the optical disc recording and / or reproducing apparatus as well as the apparatus can be easily handled. Since the outgoing light beam comes out vertically, i.e., in the Y direction shown in FIG. 1, the adjustment operation such as optical axis matching is fine in two directions (X and Y directions as shown in FIG. 1) on the case mounting surface. It is necessary to carry out by adjustment to increase the precision of the adjustment.

On the other hand, a shape without using a deflection mirror is possible. As an example, the SHG laser light beam emerges in the horizontal direction as in the second embodiment of the present invention shown in FIG.

The laser beam generator in the second embodiment of FIG. 4 includes a laser diode 41, a lens 42, a laser medium 43, reflective surfaces 44, 46R, a nonlinear crystal device 45, a concave mirror 46 ), A temperature control device 47 and a radiation plate 48. The laser diode 41 is a light beam source from which at least one pumping light beam is emitted. The lens 42 collects the pumping light beams from the laser diode 41. The laser medium 43 is rod-shaped Nd: YAG and is excited by a pumping light beam to generate a laser light beam of a fundamental frequency. The wavelength of the laser light beam at the fundamental frequency is 1064 nm, for example. A reflective surface 44, such as a dichroic mirror, is coated on the incident surface of the laser medium 43. Reflecting surface 44 such as on the reflecting surface 16 formed on the quarter wave plate 15 has a wavelength, for example, a pumping light beam transmission having a wavelength of 810 nm and a fundamental frequency generated in the laser medium 43. Selectivity of laser light beam reflection. The nonlinear photonic crystal device 45 performs second harmonic generation (SHG) with KTP (KTiOPO ₄ ). The concave mirror 46 has a reflecting surface 46R, such as a dichroic mirror, and transmits an SHG laser light beam having a wavelength of, for example, 532 nm, and reflects a laser light beam having a fundamental frequency of 1064 nm generated in the laser medium 43. Has selectivity. One temperature control device 47, such as a TE cooler, controls the temperature of the resonator consisting of the laser diode 41, the laser medium 43, the nonlinear photonic crystal device 45, and the reflecting surfaces 44, 46R. . The temperature controller 47 is installed in the radiation plate 48. The pumping light beam emitted from the laser diode 41 is collected on the laser medium 43 via the reflecting surface 44. The laser medium 43 is excited by the pumping light beam to generate a laser light beam of a fundamental frequency. The laser light beam of the fundamental frequency is radiated to the nonlinear light forming apparatus 45. The nonlinear photonic crystal device 45 generates a SHG laser light beam. Detailed descriptions of the operations and effects of the second embodiment are the same as those of the first embodiment, and thus detailed descriptions of the operations and effects thereof are omitted.

Next, a temperature control device for stably maintaining the SHG laser light beam generator while increasing the efficiency will be described below. In an embodiment of the present invention, one temperature control device such as a TE cooler simultaneously temperature-controls a light source, such as a semiconductor laser element, or a laser diode and a resonator, thereby generating a stable SHG laser light beam with low noise without reducing power. The number of components can be reduced and the reliability can be improved. On the other hand, among laser media, not only a medium having a relatively wide absorption wavelength region such as Nd: glass, but also a medium having a relatively narrow and high top dead center such as Nd: YAG.

The present invention can also be applied to a laser light beam generator using a laser medium having a relatively narrow hop number line.

The resonator 20 for generating the SHG laser light beam including the nonlinear optical defect device 18 as shown in FIGS. 1 and 2 has a phase delay amount and a temperature dependent change in the longitudinal mode, and a transformer transformation. Due to it has a stable operating range of limited temperature range. In order to obtain a higher power efficiency than a predetermined value in the stable operating region of the resonator, it is necessary to select the semiconductor laser element 11 which is absorbed by the laser medium 17 under favorable conditions in the region where the wavelength is stable. The resonator 20 may also be selected. In order to enlarge the stable operating temperature range of the resonator 20, it is effective to shorten the length of the birefringent crystal whose phase delay amount is temperature dependent or to use a crystal having a low temperature dependency.

5 is a graph showing the temperature dependence of the absorption coefficient of the solid state laser medium Nd: YAG. 6 shows a spectrum showing the wavelength on the horizontal side of the radiation beam intensity (wavelength distribution) at a temperature of 23 ° C. of a laser diode as a semiconductor laser element.

7 shows the measurement results of the effective absorption coefficient of the pumping light beam absorbed by the rod-shaped Nd: YAG having a thickness of about 1 mm during the temperature change of the laser diode. FIG. 7 shows that the temperature range R _A of the laser diode is about 2.6 ° C. in order to obtain an efficiency of 90% or more of the maximum effective absorption coefficient. The effective temperature coefficient (R _B ) of about 70-80% or higher than the maximum is about 6.7 ° C.

In this example, although the highest efficiency is low due to the wide wavelength dispersion of the laser diode as the semiconductor laser element, the acceptable temperature range for maintaining the efficiency higher than the predetermined value is wider in the example of the laser diode oscillating in single mode. Even the wavelength of a laser diode with multimode vibration is converted at a center frequency of about 0.3 nm / k. Therefore, even if the wavelength is outside the absorption line of Nd: YAG at ambient temperature or 25 ° C as a normal temperature, the absorption efficiency can be improved by adjusting the temperature change and wavelength to the Nd: YAG absorption line. At this time, the resonator generating the SHG laser light beam performs stable operation at a temperature of improved absorption efficiency.

According to an embodiment, if the laser diode is combined with the resonator 20 generating a SHG laser light beam having a stable operating temperature range of 30 ° C to 35 ° C, the temperature dependence of the phase delay amount of the nonlinear photonic crystal device such as KTP In consideration, such a laser diode may be selected that emits a laser light beam of about 809 nm (absorption line) wavelength, which shows a high absorption efficiency of Nd: YAG in the ion range. If a laser diode whose center frequency changes at about 0.3 nm / k according to temperature change is used, it is about 2.3 ± 0.7 nm shorter than 809 nm at 25 ° C to give a center wavelength of about 809 nm at 30 ° C to 35 ° C. A laser diode having a center wavelength may be used. A resonator with a stable operating temperature range of 30 ° C to 35 ° C corresponds to a resonator using a 2.5 nm long KTP.

On the other hand, if the temperature margin of the laser diode for the effective absorption coefficient of the rod-shaped Nd: YAG in the cavity of the absorption line is about ± 1.3 ℃, the center wavelength of the laser diode may be selected to be about 806.7 ± 1.1nm at 25 ℃ .

Since the temperature dependence of the phase delay change of the nonlinear photonic crystal device is proportional to the crystal length, the shorter the crystal length, the smaller the temperature change rate of the phase change. Therefore, the wider the stable temperature range, the larger the laser diode wavelength margin. . In general, since the conventional KTP uses an almost long length, the stable temperature range of the laser resonator becomes small in inverse proportion to the length of the KTP.

8 shows a resonator and laser generating a SHG laser light beam in a single temperature control device or a TE cooler, operating a laser diode by a constant current, and drawing a SHG laser light beam output shown in dotted lines and a noise level shown in solid lines at a temperature change. Show the result of the diode installed. The output indicated by the dotted line in FIG. 8 is determined by the absorption rate of the pumping light beam of the laser diode mainly into the Nd: YAG in the resonator, that is, by the effective absorption coefficient.

On the other hand, the noise level shown by the solid line in FIG. 8 is determined by the operational stability of the resonator. The temperature range (RX) to maintain an output greater than 80% of the maximum is about 3 ° C from point a to point b and the stable operating temperature range (RY) for low noise level resonators is about 4.5 from point c to d. ℃. In FIG. 8, the overlapping range RZ from point c to d is about 1.7 ° C. Therefore, by limiting this overlapping range RZ to the target temperature range for simultaneous temperature control of the laser diode and the resonator in one temperature control device, a high efficiency and stable SHG laser light beam output that maintains 80% or more of the maximum output can be obtained. Will be.

On the other hand, in order to obtain the required power within the stable temperature range RY from point c to point d by moving the dashed line in the horizontal direction in FIG. 8, the laser diode having at least one portion of the temperature range RX is provided. It may be combined with a resonator having a stable temperature range RY shown by solid lines at 8 degrees. That is, within the range that satisfies the conditions required for a single temperature controllable laser diode, the dotted line state moved to the leftmost position has the right end point (b) of the temperature range (RX) left end point of the stable temperature range (RY). (c) is reached and the dotted line state moved to the rightmost position is that point a has reached the right end point d of the stable temperature range RY. By moving the solid line in the horizontal direction in the dotted line state shown in FIG. 8, the stable temperature characteristic of the resonator can be selected as the absorption characteristic of the laser diode.

On the other hand, a temperature control device such as a TE cooler is estimated to consume the same or more power than a laser diode like a semiconductor laser element, so that one temperature control device controls both power guarantee and low noise level. This can significantly reduce the appearance size and power consumption. When the laser diode and the resonator are fixed to separate TE coolers, such a problem arises that it is difficult to show high accuracy in relative position and thermal expansion because of the relatively low structural precision of the TE coolers. However, this problem can be completely solved by controlling the temperature of both the laser diode and the resonator with a single TE cooler.

The present invention is not limited to the above embodiment, but various types of resonators may be used. For example, various resonators, such as a resonator provided with a concave mirror, may be provided on the incident surface thereof. Of course, any other laser medium or nonlinear photonic crystal device may be used, unlike Nd: YAG or KTP.

Claims (12)

A laser light beam generator, comprising: a light beam source for emitting at least one pumping light beam, a laser medium excited by the pumping light beam from the light beam source, and a nonlinear photonic crystal element provided in the extraction light path of the pumping light beam from the light source; And reflecting means constituting a resonator together with the laser medium and the nonlinear photonic crystal element, and temperature control means for controlling temperature of the light beam source and the resonator. The laser light beam generator according to claim 1, wherein said temperature control means is provided below said resonator. The apparatus of claim 1, wherein the apparatus further comprises sensing means for sensing a temperature of the resonator and applying a sensing signal to the temperature control means. The laser light beam generating apparatus according to claim 1, wherein the apparatus includes a base member on one surface of which the light beam source and the resonator are installed, and on the other side of which the temperature control means is provided. A laser light beam generator, comprising: a light beam source for emitting at least one pumping light beam, a laser medium excited by the pumping light beam from the light beam source, and a nonlinear photonic crystal element provided in the extraction light path of the pumping light beam from the light beam source Reflecting means for constructing a resonator having said laser medium and said nonlinear photonic crystal element, deflecting means for deflecting an optical path of a light beam exiting said resonator, said light beam source, said laser medium, said nonlinear crystal element, said reflecting means And a case incorporating the deflection means. 6. The laser light beam generator according to claim 5, wherein said case has means for outputting a light beam exiting from said resonator through deflection means. 6. The laser light beam generator of claim 5, wherein the size of the case is about 38 mm x 28 mm and the height of the case is about 16 mm. 6. The laser light beam generator according to claim 5, wherein the polarization direction of the light beam in the resonator lies in the S polarization of the deflection means. 6. The laser light beam generating apparatus according to claim 5, wherein said apparatus further comprises temperature control means installed below the side in said case to control said light beam source and said resonator. A laser light beam generator, comprising: a light beam source for emitting at least one pumping light beam, a laser medium excited by the pumping light beam from the light beam source, and a nonlinear photonic crystal element provided in the extraction light path of the pumping light beam from the light beam source Reflecting means for constructing the resonator having the laser medium, the nonlinear photonic crystal element, and deflecting means for deflecting the optical path of the light beam exiting the resonator, wherein the polarization direction of the light beam output from the resonator is determined by the deflection means. A laser light beam generator placed on S-polarized light. The laser light beam generator according to claim 10, wherein the deflection means is a deflection mirror having a 45 degree inclination angle. The laser light beam generator of claim 10, wherein the light source, the resonator, and the deflection means are provided in the same axis direction.