JP2006047680A - Optical system for shaping beam and laser light source and preparing method of the same system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an optical system for shaping a beam for a laser diode (LD), whose miniaturization is easy and in which the utilization efficiency of exciting rays of light is high, and whose mounting is easy. <P>SOLUTION: An optical system for shaping a beam 13 which has a stripe-shaped light source shape and which contracts or condenses divergent angles of at least orthogonal direction of outgoing rays of light of the LD 11 which emits laser beams having different divergent angles in a direction orthogonal to a stripe and a direction parallel with the stripe is characterized in being equipped with substrates 14, 15 having two sheets of reflecting surfaces 1, 2 which are arranged across a face including the stripe and the optical axis of the LD 11. At least on the reflecting surface on one substrate, an inclined part is formed so that a spacing of opening parts from which laser beams are emitted may become wider than that of opening parts on which laser beams are made incident. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a beam shaping optical system, a laser light source using the beam shaping optical system, and a method for producing the beam shaping optical system.

Conventionally, as a technique related to a laser light source and an apparatus using a laser diode, for example, the following has been proposed.
Patent Document 1 (Japanese Patent Laid-Open No. 09-199774) discloses a laser diode-pumped solid-state laser device using a linear array LD (laser diode) or a stacked two-dimensional linear array LD as a pumping light source. 10 (a) and 10 (b) are focused on improving laser oscillation efficiency in the TEM ₀₀ mode, shortening the pulse width during Q-switch pulse oscillation, and reducing the size of the laser device. as shown, thereby efficiently collecting once to about φ2 millimeters using LD excitation light emitted from the two-dimensional linear array LD101 cylindrical lenses 102, 103 and coupling optics 120 ₁ consisting of spherical lenses 104 and 105, then, Tapered total reflection rod 10 having an incident part of 2 to 3 mm and an exit part of about 0.5 to 1 mm. Consists of six coupling optical system composed of two stages of the condensing optical system to bind to _1, the total reflection rod 106 ₁ of the exit portion of the tapered is Rui surface optically coupled total reflection coating side of the laser medium 107 A laser diode-pumped solid state laser device having a configuration in which the laser diodes are brought into contact with each other with no gap is disclosed.

  Patent Document 2 (Japanese Patent Laid-Open No. 11-017252) shows a semiconductor-pumped solid-state laser that can efficiently propagate pumping light output from a semiconductor laser (LD) to a laser medium as shown in FIG. As described above, the shape of the optical guide plate 205 that guides the excitation light emitted from the semiconductor laser element 203 to the solid-state laser medium 201 is increased by increasing the sectional area on the semiconductor laser element 203 side and decreasing the sectional area on the fixed laser medium 201 side. A semiconductor-excited solid-state laser device configured as described above is disclosed.

  Patent Document 3 (Japanese Patent Laid-Open No. 11-214776) provides an LD-pumped solid-state laser capable of increasing the output of an LD-pumped solid-state laser without increasing the output of a pumping semiconductor laser (LD). As shown in FIG. 12, in an LD-pumped solid-state laser that performs laser oscillation by optically pumping a solid-state crystal 301 that is a laser medium using a semiconductor laser 302 as a pumping light source, irradiation of the solid-state crystal 301 of the semiconductor laser 302 is performed. An LD-excited solid-state laser having a light condensing means 305 for condensing light is disclosed.

JP 09-199774 A Japanese Patent Laid-Open No. 11-017252 Japanese Patent Application Laid-Open No. 11-214776

  As a laser light source capable of obtaining high output with high energy efficiency, a laser diode pumped solid state laser (DPSSL) has been attracting attention. This is because a laser diode (LD) can be used to efficiently excite a specific energy level of a laser crystal, so that the excitation efficiency is high, which is advantageous for high output and miniaturization of the apparatus. It is used in various devices using a laser, such as a laser scan display, a laser measurement device, a medical device, and an analysis device.

  In these apparatuses, various studies have been made to increase the efficiency of excitation by the LD. The LD used for excitation of the laser light source usually has a broad area structure. In this LD, the light emitting points are striped, and the spread angle varies greatly depending on the direction. For example, in a type that can output about 1 W, the stripe shape is 1 μm in length and 200 μm in width, and the divergence angle is 40 ° in the direction orthogonal to the stripe (fast axis side) and about 10 ° in the direction parallel to the stripe (slow axis side). is there. For this reason, in order to efficiently excite the laser crystal, an optical system for efficiently transmitting the light emitted from the LD to the laser crystal is important.

  Therefore, in Patent Document 2 described above, excitation light from the LD 203 is propagated to the laser crystal 201 using a tapered light guide plate 205. In Patent Document 3, the excitation light from the LD 302 is condensed using a condensing means 305 such as a cylindrical lens, and the solid crystal 301 as a laser medium is irradiated. In this case, a rod-shaped cylindrical lens is also used as the condensing means 305. However, when condensing light spreading in the vertical direction, it is necessary to use a cylindrical lens having a very large NA, so that alignment is difficult. Become.

On the other hand, in order to perform efficient oscillation with an LD-pumped solid-state laser, it is necessary to match the laser oscillation region in the laser crystal with the region irradiated with the excitation light as much as possible. Since the light emission point of the excitation LD is in a stripe shape, the light collecting spot shape becomes a stripe shape simply by condensing with the lens, so that an optical system for converting the beam shape is required. For example, in an edge-pumped solid-state laser aiming at the TEM ₀₀ mode, the shape of the pump light is shaped into a circle to improve the overlap (mode matching) between the LD pump light and the laser beam oscillating in the resonator. It is necessary to narrow the diameter to the same level as the laser beam to be used. Therefore, in Patent Document 1 mentioned above, it is irradiated with excitation light from the LD101 by combining light guide 106 of the _plurality of lenses 102 to 105 and tapered to the laser crystal 107 _1.

However, these methods increase the size of the excitation optical system and make it difficult to reduce the size of the laser device. In order to reduce the excitation optical system, for example, the taper angle of the light guide may be increased, but in this case, the reflection efficiency of the excitation light is reduced because the reflection of the beam increases. Moreover, when using a some lens like patent document 1, optical system itself becomes large. Further, when a plurality of lenses are used in combination, high mounting accuracy is required, so that mounting becomes difficult.
In the above-described end face excitation type solid-state laser, the size of the laser crystal is about several mm and the LD chip is about 1 mm, and downsizing the excitation optical system to about several millimeters contributes to downsizing of the laser device. is important.

In order to solve the above-described problems of the prior art, the present invention has an object to provide a beam shaping optical system that can be easily downsized, has high use efficiency of excitation light, and is easy to mount, and a laser light source using the same. And
More specifically, it is an object of the present invention to provide a beam shaping optical system for a laser diode that can be easily miniaturized, has high use efficiency of excitation light, and is easy to mount.
In addition to the above object, an object of the present invention is to provide a beam shaping optical system that can be further miniaturized.
Furthermore, an object of the present invention is to provide a beam shaping optical system with high uniformity of emitted light in addition to the above object.
Furthermore, an object of the present invention is to provide a substrate material for easily creating a beam shaping optical system in addition to the above object.
A further object of the present invention is to provide a small laser light source that can efficiently excite a solid laser crystal.
Furthermore, an object of the present invention is to provide a production method capable of easily producing the beam shaping optical system of the present invention in addition to the above object.

In order to achieve the above object, the present invention adopts the following means.
The first means of the present invention has a striped light source shape, and has a divergence angle in at least the orthogonal direction of the emitted light of a laser diode (LD) that emits laser light having a divergence angle different in a direction parallel to the stripe and perpendicular to the stripe. A beam shaping optical system for reducing or condensing, comprising: a substrate having two reflecting surfaces arranged across a surface including a stripe and an optical axis of the laser diode (LD); and at least one of the substrates The reflecting surface is provided with an inclined portion formed so that an interval between the opening portions from which the laser is incident is increased with respect to the opening portions into which the laser is incident.

According to a second means of the present invention, in the beam shaping optical system of the first means, the inclined portion of the reflecting surface of the substrate is a concave surface (claim 2).
The third means of the present invention is characterized in that, in the beam shaping optical system of the first or second means, at least a part of the reflecting surface has a function of a diffusion plate.
Further, a fourth means of the present invention is characterized in that, in the beam shaping optical system of any one of the first to third means, silicon or quartz glass is used as a material of the substrate. Item 4).

  A fifth means of the present invention is a laser light source, comprising a laser diode (LD) and a beam shaping optical system of any one of the first to fourth means, wherein the laser diode (LD) The beam shaping optical system is mounted in the same package.

The sixth means of the present invention has a striped light source shape and has a divergence angle in at least the orthogonal direction of the emitted light of a laser diode (LD) that emits laser light having a different divergence angle in a direction parallel to the stripe and perpendicular to the stripe. A beam shaping optical system for reducing or condensing, comprising: a substrate having two reflecting surfaces arranged across a surface including a stripe and an optical axis of the laser diode (LD); and at least one of the substrates The reflecting surface is provided with an inclined portion formed so that the interval between the opening portion where the laser is incident and the opening portion where the laser is incident is increased, and light is emitted from the bottom of the substrate of the laser diode (LD) that performs beam shaping. height D _L up _section, height D _BL from the bottom of the mounting side of the substrate of the beam shaping optical system to the bottom of the opening portion of the incident _side, the height of the upper D _BH If it is,
_DBL <D _L <D _BH
(Claim 6).

According to a seventh means of the present invention, in the beam shaping optical system according to the sixth means, the inclined portion of the reflecting surface of the substrate is a concave surface.
According to an eighth means of the present invention, in the beam shaping optical system of the sixth or seventh means, at least a part of the reflecting surface has a function of a diffuser.
Further, a ninth means of the present invention is characterized in that, in the beam shaping optical system of any one of the sixth to eighth means, silicon or quartz glass is used as a material for the substrate. Item 9).

  A tenth means of the present invention is a laser light source, comprising a laser diode (LD) and a beam shaping optical system of any one of the sixth to ninth means, wherein the laser diode (LD) The beam shaping optical system is mounted in the same package (claim 10).

According to an eleventh means of the present invention, there is provided a beam shaping optical system producing method for producing a beam shaping optical system according to any one of the first to fourth and sixth to ninth means. A step of creating a resist pattern having an inclined portion on at least one surface of a substrate having a surface, a step of transferring the shape of the resist pattern to the substrate by anisotropic dry etching, and a spacer for defining the interval between the reflecting surfaces And a step of bonding two substrates through the substrate (claim 11).
The twelfth means of the present invention is characterized in that, in the eleventh means for producing a beam shaping optical system, a gray scale mask is used when creating the resist pattern. .
Further, the thirteenth means of the present invention is the method for producing a beam shaping optical system of the eleventh means, wherein when the resist pattern is produced, a pattern for spacers is formed simultaneously with the inclined portion, and a necessary spacer is formed. When the height of h is h and the height of the spacer pattern is h ′,
h ′ ≧ h / s
s: etching selectivity = substrate etching rate / resist etching rate (claim 13).

  The beam shaping optical system according to the first means of the present invention includes a substrate having two reflecting surfaces arranged across a surface including a stripe of a laser diode (LD) and an optical axis, and at least one substrate The reflecting surface of the laser beam is provided with an inclined portion formed so that the interval between the opening portion where the laser is incident and the opening portion where the laser beam is incident is increased, so that the light emitted from the LD can be taken in without waste. Since the beam distribution in the fast axis direction can be suppressed and the excitation light distribution according to the laser medium can be formed, the excitation efficiency can be increased. In addition, since there is a large margin for misalignment during mounting, mounting can be performed easily.

In the beam shaping optical system of the second means, in addition to the effect of the first means, the length of the excitation optical system can be suppressed by making the reflecting surface concave, so that the size can be further reduced. .
In addition, in the beam shaping optical system of the third means, in addition to the effects of the first or second means, a part of the reflection surface is used as a diffusion plate so that the emitted light is more randomly superimposed. Therefore, outgoing light with high light uniformity can be obtained.
Further, in the beam shaping optical system of the fourth means, in addition to the effects of any of the first to third means, the beam shaping optical system of the present invention can be obtained by using silicon or quartz glass for the substrate. The process for creating becomes easier.

  The laser light source of the fifth means includes a laser diode (LD) and the beam shaping optical system of any one of the first to fourth means, and the laser diode (LD) and the beam shaping optics. Since the optical system for beam shaping is very small because the system is mounted in the same package, it can be easily mounted on the same package or the same substrate as the LD. It is possible to realize a laser light source capable of efficiently exciting the light.

The beam shaping optical system of the sixth means comprises a substrate having two reflecting surfaces arranged across a surface including the stripe of the laser diode (LD) and the optical axis, and the reflecting surface of at least one of the substrates Is provided with an inclined portion formed so as to increase the interval between the opening portion where the laser is incident and the opening portion where the laser is incident, from the bottom of the substrate of the laser diode (LD) that performs beam shaping to the light emitting portion. Is D _L , the height from the bottom of the substrate on the mounting side of the beam shaping optical system to the lower part of the opening on the incident side is D _BL , and the height to the upper part is D _BH .
_DBL <D _L <D _BH
By satisfying the above, it is possible to capture the light emitted from the LD without waste and suppress the spread of the beam in the fast axis direction to form the distribution of the excitation light according to the laser medium, so that the excitation efficiency can be increased. In addition, since there is a large margin for misalignment during mounting, mounting can be performed easily. Further, since it can be mounted on the same substrate as the LD chip, further miniaturization becomes possible.

In the beam shaping optical system of the seventh means, in addition to the effect of the sixth means, by making the reflecting surface concave, the length of the excitation optical system can be suppressed, so that the size can be further reduced. .
In addition, in the beam shaping optical system of the eighth means, in addition to the effects of the sixth or seventh means, a part of the reflection surface is used as a diffusion plate, so that the emitted light is superimposed more randomly. Therefore, outgoing light with high light uniformity can be obtained.
Further, in the beam shaping optical system of the ninth means, in addition to the effects of any of the sixth to eighth means, the beam shaping optical system of the present invention can be obtained by using silicon or quartz glass for the substrate. The process for creating becomes easier.

  The laser light source of the tenth means comprises a laser diode (LD) and the beam shaping optical system of any one of the sixth to ninth means, and the laser diode (LD) and the beam shaping optics. Since the optical system for beam shaping is very small because the system is mounted in the same package, it can be easily mounted on the same package or the same substrate as the LD. It is possible to realize a laser light source capable of efficiently exciting the light.

In an eleventh means for producing a beam shaping optical system, a resist pattern having an inclined portion on at least one substrate on a substrate having two flat surfaces and a resist by anisotropic dry etching A step of transferring the shape of the pattern to the substrate, and a step of bonding the two substrates through a spacer for defining the distance between the reflecting surfaces, thereby providing a beam shaping optical system using a semiconductor process; Since it can be produced, it is possible to easily produce a large amount of minute beam shaping optical systems.
Further, in the twelfth means for forming the beam shaping optical system, in addition to the effects of the eleventh means, a gray scale mask is used. Therefore, the inclined portion, the spacer, and the resist pattern for forming the diffusion plate are provided. It is possible to create a single beam, and it is possible to easily create a large amount of minute beam shaping optical systems.
Further, in the beam shaping optical system creating method of the thirteenth means, in addition to the effect of the eleventh means, the resist in the spacer portion is not removed during the etching, so that the spacer having a height necessary for adjusting the etching amount is obtained. Can be created simultaneously with the inclined pattern.

  The optical system for beam shaping in the present invention sandwiches a plane including the slow axis and the optical axis of the laser diode (LD) in order to reduce or condense at least the divergence angle of the emitted light of the laser diode (LD) in the fast axis direction. A substrate having two reflection surfaces arranged is provided, and at least one of the reflection surfaces of the substrate is provided with an inclined portion formed so that a gap between the opening portion from which the laser is incident is increased. It is characterized by being. When the light emitted from the laser diode (LD) passes through the beam shaping optical system, light having a larger inclination with respect to the reflection surfaces of the two substrates is repeatedly reflected between the reflection surfaces of the two substrates. Propagates to the opening on the exit side. At this time, since an inclined portion is provided between the two reflecting surfaces so that the opening on the emission side is wider than the opening on the incident side, the spread angle of the laser beam becomes smaller during repeated reflections. This divergence angle can be adjusted freely according to the length and angle of the inclined part, the width of the exit-side opening, etc., so that excitation suitable for the shape of the laser medium to be pumped and the profile of the laser output therefrom is performed. Will be able to. In addition, since such a structure can be relatively easily created by using a semiconductor process, it is easy to miniaturize and mass-produce. In addition, if it is made small to the same size as the LD chip, it can be mounted on the same substrate as the LD chip, so the entire excitation optical system including the LD chip and the beam shaping optical system It can be made small. Furthermore, when mounting the laser diode (LD), the light emitted from the laser diode may be incident on the incident-side opening of the beam shaping optical system, so that there is a large alignment margin. Alignment is also easier than with an optical system.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

[Example 1]
First, an embodiment according to the first to third means of the present invention will be described.
FIG. 1 shows an embodiment of a beam shaping optical system according to the present invention. 1A is a cross-sectional view of an LD and a beam shaping optical system including a fast axis of a laser diode (LD), and FIG. 1B is a cross-sectional view of the LD and a beam shaping optical system including a slow axis of the LD. . In FIG. 1, a chip-like LD (LD chip) 11 is mounted on a laser chip mount 12, and a beam shaping optical system 13 is disposed in the vicinity of the emission side end face of the LD 11. The beam shaping optical system 13 is composed of two substrates 14 and 15 having reflecting surfaces 1 and 2 bonded via a trapezoidal spacer 16 having a height on the exit side larger than the height on the entrance side. , Where d is the distance between the incident-side openings with respect to the fast axis direction and d ′ is the distance between the exit-side openings, d <d ′, and the respective reflecting surfaces 1 and 2 are arranged in parallel. An inclination of angle θ is given.

Here, the results of obtaining the distribution of the laser beam emitted from the LD 11 and passing through the beam shaping optical system 13 by the ray tracing method are shown in FIGS. In this calculation, the parameters of the beam shaping optical system 13 are as follows: d = 20 μm, θ = 5 °, L = 600 μm, d ′ = 125 μm, the emitted light distribution on the fast axis side of the LD 11 is a Gaussian distribution, half-width (1 / e ² width) is 40 ° (half angle, hereinafter, all emission angles are half angle), 1 / e ² width of slow axis side emission angle is 10 °, and stripe width is 100 μm. FIG. 2A is a diagram showing a change in light intensity distribution at a distance I from a light source (LD) of laser light that has passed through a beam shaping optical system. The light intensity distribution has a staircase shape because light beams having different numbers of multiple reflections are superimposed in the beam shaping optical system. If the length L of the optical system is increased to increase the number of reflections, the level difference is reduced, but the optical system is increased and the loss due to reflection is also increased. If a part of the optical reflecting surface is a diffuser plate that reflects light at a random angle, the step of the light intensity distribution can be reduced, and the unevenness of the light intensity that is particularly problematic in the slow axis direction can be reduced. From the result of this ray tracing, it can be seen that at the position of I = 1000 μm, the 1 / e ² width in the fast axis direction is 230 μm and the 1 / e ² width on the slow axis side is 274 μm, resulting in a substantially circular beam profile. Further, the spread angle of the emitted light from the beam shaping optical system 13 is converted to 15.8 ° by the change in the 1 / e ² width. FIG. 2B shows the result of calculation under the same conditions as in FIG. 2A with d = 30 μm. In this case, the spread angle of the emitted light is 18.2 °. The intensity distribution and divergence angle of the beam can be adjusted by adjusting the angle θ, the length L, and the distance d of the reflecting surface. Therefore, when the laser crystal is excited, by using this beam shaping optical system 13, only necessary portions can be easily excited efficiently.

  3 and 4 show the change in the light intensity distribution and the change in the total amount of light that are propagated when the position between the laser diode and the beam shaping optical system is shifted. More specifically, FIGS. 3A and 3B show changes in the light intensity distribution and changes in the amount of light when the distance sz between the laser diode (LD) 11 and the beam shaping optical system 13 in FIG. 1 changes. FIG. In this case, even when sz is 8 μm, there is almost no change in the light intensity distribution, and 99% of the amount of light when sz = 0 μm is secured. 4A and 4B are diagrams showing changes in the light intensity distribution and changes in the amount of light when the optical axes of the laser diode (LD) 11 and the beam shaping optical system 13 in FIG. 1 are shifted by sy. is there. Even when sy changes, the light intensity distribution is almost symmetrical, and the change in the beam propagation direction can be suppressed as compared with the case where a lens is used. The change in the amount of light is obtained for sz = 4 μm, 6 μm, and 8 μm. However, even when sz = 8 μm, sy = 4 μm can secure 96% of light. Thus, the beam shaping optical system 13 of the present invention is easy to mount because there is little change in the amount of light that can be propagated even with a positional shift and the propagation direction. Can also have a large tolerance.

  In the embodiment shown in FIG. 1, the case where the reflecting surfaces 1 and 2 of the two substrates 14 and 15 of the beam shaping optical system 13 are flat has been described. A concave surface as shown in FIG. 6 or a shape in which only a part as shown in FIG. As shown in FIG. 5, when concave surfaces are used for the reflecting surfaces 1 and 2, the radiation angle can be reduced even with a smaller number of reflections than a flat surface, so that the length L of the excitation optical system can be shortened. . In the case of a shape in which only a part of the reflecting surfaces 1 and 2 is inclined as shown in FIG. 6, the length of the parallel portion of the reflecting surfaces 1 and 2 is adjusted according to the arrangement of the optical system. As a result, it is possible to irradiate the laser beam at an arbitrary position while maintaining the radiation angle and the beam width.

[Example 2]
Next, embodiments of the means according to the fifth, sixth, seventh, eighth and tenth aspects of the present invention will be described.
FIG. 7 shows an embodiment of a laser light source 20 in which the beam shaping optical system of the present invention and a laser diode chip (LD chip) are combined. In FIG. 7, the LD chip 11 and the beam shaping optical system 13 are mounted on a heat sink 17 which also serves as a substrate. As in FIG. 1, the LD chip 11 is mounted on the laser chip mount 12, and a beam shaping optical system 13 is disposed in the vicinity of the emission side end face of the LD 11.

The beam shaping optical system 13 of this embodiment is about the same size as the LD chip 11 and is resistant to misalignment due to temperature changes and the like, so it can be contained in one package with the configuration shown in FIG. Is possible. That is, in the laser light source 20 having the configuration shown in FIG. 7, the heat sink 17 serving as a substrate is fixed on the base 19 of the package, and the LD chip 11 is fixed on the heat sink 17 via the laser chip mount 12. A beam shaping optical system 13 is arranged in the vicinity of the end face on the emission side of the LD 11 and is fixed to the heat sink 17. These members are housed in a package 18 having a light exit window.
Thus, since the beam shaping optical system 13 of the present invention can be easily mounted in the same package as the LD 11, it is possible to realize a laser light source 20 that is smaller and can efficiently excite a solid laser crystal.
When a solid-state laser device is configured using the laser light source 20, although not shown, a laser medium is disposed outside the light emission window of the laser light source 20, and the laser light emitted from the laser light source 20 is converted into a laser. The medium will receive.

Next, FIG. 8 shows an embodiment of a beam shaping optical system that is further easily mounted. In FIG. 8, the LD chip 11 and the beam shaping optical system 13 are mounted on one substrate 21. In this example, the height from the bottom of the substrate of the LD chip 11 to the light emitting portion is D _L , the height from the bottom of the substrate on the mounting side of the beam shaping optical system 13 to the lower portion of the opening on the incident side is D _BL , _Let D _{BH be} the height to the top,
_DBL <D _L <D _BH
The substrate thickness of the beam shaping optical system 13 was set so as to satisfy the above. By doing so, the optical axis of the laser chip 11 is always inside the opening of the beam shaping optical system 13 in a state where the laser chip 11 and the beam shaping optical system 13 are directly mounted on one substrate 21. As a result, there is no need to adjust the height during mounting, and mounting is easy. Even in such a configuration, the reflecting surface of the beam shaping optical system 13 can use a concave surface or a shape in which only a part thereof is inclined as in the case of the first embodiment.
In the embodiment of FIG. 8, since the LD chip 11 and the beam shaping optical system 13 are mounted on one substrate 21, it is resistant to misalignment due to a temperature change and the like, as in FIG. The laser light source can be configured in one package.

[Example 3]
Next, embodiments of the means according to the fourth, ninth, eleventh, twelfth and thirteenth aspects of the present invention will be described.
FIG. 9 shows an embodiment of a method for creating a beam shaping optical system. This production method mainly uses photolithography and dry etching processes used in the production of semiconductors and MEMS. As the substrate 14, a silicon (Si) substrate that can be easily processed by these processes and is easily available is used. In addition, a quartz glass substrate or the like can be easily processed, and is suitable for creating this beam forming optical system. Although only one beam shaping optical system is shown in FIG. 9, in practice, a plurality of optical systems are collectively formed on a wafer-like substrate and then cut into individual optical systems by dicing or the like. Thus, a plurality of optical systems are created simultaneously.

In FIG. 9, first, the thickness of the substrate is adjusted by polishing so that the opening on the incident side has a predetermined height (not shown). Next, (1) a photoresist 22 is applied on the silicon substrate 14 and dried, and then (2) a beam shaping optical system pattern is exposed using a photolithography technique, followed by development and rinsing. Then, a pattern of the photoresist 22 (resist pattern 22 ′) is created. When exposing the resist pattern 22 ', a gray scale mask capable of modulating the transmittance was used as a photomask in order to simultaneously form an inclined portion and a spacer portion serving as a reflection surface. In addition, by using a gray scale mask, it is possible to form a minute unevenness on a part of the reflecting surface to have the function of a diffusion plate. The spacer pattern needs to have the required height of the spacer transferred to the substrate 14 before all the resist in the spacer part is removed so that the height of the spacer can be adjusted by etching. . Therefore, when the required spacer height is h and the height of the spacer pattern is h ′,
h ′ ≧ h / s
It is necessary that s: etching selectivity = substrate etching rate / resist etching rate.

  Subsequently, (3) anisotropic dry etching is performed using the resist pattern 22 ′ as an etching mask to transfer the resist pattern to the silicon substrate 14. Here, a relatively deep etching of several tens of μm is required. However, if a high-speed etcher using high-density plasma such as an ICP etcher is used, the etching can be easily performed. Next, (4) the reflective film 23 is coated on the substrate surface as necessary. Coating a reflective film or antireflection film on a minute optical component is quite difficult due to problems such as the fixing method, but in this example, since a plurality of optical components are created on a large substrate, Coating can be performed easily.

  Next, (5) another substrate 15 in which the spacer portion and the reflective film 24 are formed in the same step is formed on the substrate 14 in which the spacer portion and the reflective film 23 are formed in the steps (1) to (4). to paste together. (6) Thereafter, a plurality of beam shaping optical systems are obtained by cutting the bonded substrates 14 and 15 on which a plurality of optical systems are collectively formed by dicing or the like and dividing them into individual optical systems. 13 can be completed simultaneously. By using such a production method, the beam shaping optical system of the present invention can be easily produced, and mass production can be achieved.

  As described above, the present invention realizes a beam shaping optical system for a laser diode that can be easily downsized, has high use efficiency of excitation light, has high uniformity of emitted light, and is easy to mount. Can do. Therefore, by using this beam shaping optical system, it is possible to realize a small-sized laser light source that can efficiently excite a solid laser crystal. This laser light source can be applied to a laser diode-excited solid-state laser device, and can be used in various devices using a laser such as a laser processing device, a laser printer, a laser scan display, a laser measurement device, a medical device, and an analysis device. it can.

1A and 1B are diagrams showing an embodiment of a beam shaping optical system according to the present invention, in which FIG. 1A is a cross-sectional view of an LD including a fast axis of an LD and a beam shaping optical system, and FIG. It is sectional drawing of LD and the optical system for beam shaping containing. It is a figure which shows the change of the light intensity distribution in the distance from the light source (LD) of the laser beam which passed through the beam shaping optical system shown in FIG. It is a figure which shows the change of light intensity distribution and the change of light quantity when the distance sz of the laser diode (LD) in FIG. 1 and the beam shaping optical system changes. It is a figure which shows the change of the light intensity distribution when the optical axis of the laser diode (LD) in FIG. 1 and the beam shaping optical system has shifted | deviated by sy, and the change of light quantity. It is a schematic sectional drawing which shows another Example of the optical system for beam shaping which concerns on this invention. It is a schematic sectional drawing which shows another Example of the optical system for beam shaping which concerns on this invention. It is a schematic sectional drawing which shows one Example of the laser light source which combined the optical system for beam shaping of this invention, and LD chip | tip. It is a schematic sectional drawing which shows another Example of the optical system for beam shaping which concerns on this invention. It is process explanatory drawing which shows one Example of the production method of the optical system for beam shaping which concerns on this invention. It is structure explanatory drawing of the solid-state laser apparatus which shows an example of a prior art. It is a schematic sectional drawing of the solid-state laser apparatus which shows another example of a prior art. It is a schematic sectional drawing of the solid-state laser apparatus which shows another example of a prior art.

Explanation of symbols

1, 2: Reflecting surface 11: Laser diode (LD)
12: Laser chip mount 13: Beam shaping optical system 14, 15: Substrate 16: Spacer 17: Heat sink 18: Package 19: Base 20: Laser light source 21: Substrate 22: Photo resist 22 ′: Resist pattern 23, 24: Reflection film

Claims (13)

Beam shaping optical system for reducing or condensing the divergence angle in at least the orthogonal direction of the emitted light of a laser diode having a stripe-shaped light source shape and emitting laser light having a divergence angle different from that in a direction orthogonal to the stripe. In
A substrate having two reflecting surfaces arranged across a surface including the stripe and the optical axis of the laser diode, and an opening portion that emits at least one of the reflecting surfaces of the substrate to the opening portion where the laser is incident An optical system for beam shaping, characterized in that an inclined portion formed so as to increase the interval is provided. The beam shaping optical system according to claim 1,
An optical system for beam shaping, wherein the inclined portion of the reflecting surface of the substrate is a concave surface. The beam shaping optical system according to claim 1 or 2,
A beam shaping optical system, wherein at least a part of the reflecting surface has a function of a diffusion plate. The beam shaping optical system according to any one of claims 1 to 3,
A beam shaping optical system using silicon or quartz glass as a material of the substrate.   A laser diode and the beam shaping optical system according to claim 1, wherein the laser diode and the beam shaping optical system are mounted in the same package. A laser light source. Beam shaping optical system for reducing or condensing the divergence angle in at least the orthogonal direction of the emitted light of a laser diode having a stripe-shaped light source shape and emitting laser light having a divergence angle different from that in a direction orthogonal to the stripe. In
A substrate having two reflecting surfaces arranged across a surface including the stripe and the optical axis of the laser diode, and an opening portion that emits at least one of the reflecting surfaces of the substrate to the opening portion where the laser is incident Is formed so that the distance between the bottom of the substrate of the laser diode for beam shaping and the light emitting portion is D _L , and the height of the substrate on the mounting side of the beam shaping optical system is the height from the bottom portion to the bottom of the opening portion of the incident side D _BL, until upper height when the D _BH,
DBL <D _L <D _BH
An optical system for beam shaping characterized by satisfying The beam shaping optical system according to claim 6,
An optical system for beam shaping, wherein the inclined portion of the reflecting surface of the substrate is a concave surface. The beam shaping optical system according to claim 6 or 7,
A beam shaping optical system, wherein at least a part of the reflecting surface has a function of a diffusion plate. The beam shaping optical system according to any one of claims 6 to 8,
A beam shaping optical system using silicon or quartz glass as a material of the substrate.   A laser diode and the beam shaping optical system according to claim 6, wherein the laser diode and the beam shaping optical system are mounted in the same package. A laser light source. In the creation method of the beam shaping optical system which creates the beam shaping optical system according to any one of claims 1 to 4 and 6 to 9,
The step of creating a resist pattern having an inclined portion on at least one substrate on a substrate having two flat surfaces, the step of transferring the shape of the resist pattern to the substrate by anisotropic dry etching, and the interval between the reflecting surfaces And a step of bonding two substrates through a spacer for defining. A method for producing a beam shaping optical system. The method for producing an optical system for beam shaping according to claim 11,
A method for producing a beam shaping optical system, wherein a gray scale mask is used when producing the resist pattern. The method for producing an optical system for beam shaping according to claim 11,
When creating the resist pattern, a spacer pattern is formed at the same time as the inclined portion, and when the required spacer height is h and the spacer pattern height is h ′,
h ′ ≧ h / s
s: etching selectivity = substrate etching rate / resist etching rate. A method for producing a beam shaping optical system.

Images