JP2006310604A - Laser light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid laser light source of semiconductor laser excitation using a passive Q switching technology which shortens a resonator length so as to get high peak power and is obtained at a low cost. <P>SOLUTION: The laser light source 100 is provided with a resonator 30 comprised of a laser medium 10 and a saturable absorbing material 20 as a Q switch element, and an excitation source 40. The exit face 12 of the laser medium 10 and the incidence face 21 of the saturable absorbing material 20 are brought into contact with each other, a part of the face 12 and a part of the face 21 separate from each other through a space portion 60, a first coating film 51 to transmit excitation light L1 and to fully reflect light L2 emitted from the laser medium 10 is formed on the incidence face 11 of the laser medium 10, a second coating film 52 to transmit a part of the light L2 emitted from the laser medium 10 and to reflect the rest is formed on the exit face 22 of the saturable absorbing material 20, and the light L2 emitted from the laser medium 10 passes through the space 60. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser light source that outputs high-power, short-pulse laser light using Q switching technology, and in particular, includes a laser medium, a saturable absorber as a Q switch element, and the laser medium and saturable absorber. The present invention relates to a solid-state laser light source pumped by a semiconductor laser using a resonator and passive Q switching technology including a pump source.

  Laser light sources are being researched and developed for higher output power, shorter pulses, and shorter wavelengths. Among them, a laser light source using the Q switching technique is attracting attention as being capable of outputting a high-power, short-pulse laser beam.

  In the Q switching technology, not only a laser medium but also a Q switch element is included in the resonator, and the laser oscillation is controlled by changing the Q value of the resonator by the Q switch element, and output is thereby performed. The laser light has a short pulse and a high power.

  Among Q switching technologies, a solid-state laser light source pumped by a semiconductor laser using a passive Q switching technology using a saturable absorber as a Q switch element is preferable in that the configuration is simple and small (for example, Patent Documents). 1).

  This is configured by a general configuration including a laser medium, a saturable absorber, a resonator in which the laser medium and the saturable absorber are arranged on a resonance optical path, and an excitation source.

  The laser medium emits light when excited, and the laser medium is excited when the excitation light from the excitation source enters.

  In addition, the saturable absorber absorbs incident light when the incident light power is equal to or lower than the absorption saturation threshold, but the incident light power exceeds the absorption saturation threshold. The absorption is saturated and transparent. The saturable absorber is used as a passive Q switch element by utilizing such properties.

  In addition, the resonator resonates the light emitted from the laser medium when the saturable absorber is transparent, and emits a part of the light from the exit surface of the saturable absorber. The laser medium and the saturable absorber disposed on the resonant optical path are independent, and a reflecting mirror (mirror) is independently disposed outside the laser medium and the saturable absorber. Is.

  Here, in this pair of reflecting mirrors, the one located on the laser medium side has a function of transmitting the excitation light from the excitation source and totally reflecting the light emitted from the laser medium, and is saturable. What is located on the absorber side has a function of transmitting a part of the light emitted from the laser medium and reflecting the remaining part. By giving such a function to each reflecting mirror, light is resonated in the resonator.

  A laser light source using a saturable absorber as such a Q switch element operates as follows.

  Since the inversion distribution of the laser medium is small at the beginning of excitation of the laser medium, the power of the light emitted from the laser medium and incident on the saturable absorber is small. Therefore, at the beginning of the excitation of the laser medium, the saturable absorber has a large absorption and is opaque, so that the Q value of the resonator is small and laser oscillation does not occur.

  The laser medium continues to be excited even during the period when the resonator has a small Q value and the laser does not oscillate. The inversion distribution of the laser medium gradually increases, and the power of the light emitted from the laser medium and incident on the saturable absorber. Will gradually grow.

Eventually, when the power of light emitted from the laser medium and incident on the saturable absorber exceeds the absorption saturation threshold, the saturable absorber suddenly decreases in absorption (that is, becomes transparent), and the resonator Q value becomes As it becomes larger, stimulated emission proceeds rapidly in the laser medium, and as a result, laser oscillation occurs. In this way, high power and short pulse laser light is output from the resonator.
JP 2003-198019 A

  By the way, in the above-described conventional laser light source, as one method for increasing the power, a method is adopted in which the peak power is increased by shortening the distance between the reflecting mirrors, that is, by shortening the resonator length to shorten the pulse. .

  However, conventionally, a laser medium, a saturable absorber that is a passive Q switch element, and a pair of reflecting mirrors are arranged separately from each other in order to provide parallelism between these components. It is necessary to make adjustments.

  Therefore, it takes time and cost to produce each parallelism between the above components, and again, it is necessary to make adjustments to obtain the parallelism of the pair of reflectors located at both ends of the resonator. It takes time and effort. Moreover, since it is difficult to accurately reproduce, there is a problem that it is difficult to make a plurality of the same items.

  In addition, it is necessary to leave a certain gap between the independent components in the resonator so that the surfaces of the components hit each other so that there is no damage to the surfaces. It is necessary to create a certain gap between them, which increases the resonator length.

  For such a problem, the laser medium and the saturable absorber are integrated by joining the exit surface of the laser medium and the entrance surface of the saturable absorber, and both ends of the integrated member, that is, the laser medium. It is conceivable to coat a film functioning as a reflecting mirror on the incident surface and the exit surface of the saturable absorber.

  According to such a method, since the resonator can be integrated with a laser medium, a saturable absorber, and a pair of reflecting mirrors, which have been conventionally independent, the resonator is small, the resonator length is short, and the peak power is reduced. A configuration that can be made higher can be realized. In addition, the vibration resistance can be improved by integrating the components.

  However, with such a configuration, there arises a problem that the method of joining the laser medium and the saturable absorber is limited. For example, when an adhesive is used for joining the laser medium and the saturable absorber, light transmission between the laser medium and the saturable absorber is inhibited by the adhesive.

  Therefore, it is necessary to bond the laser medium and the saturable absorber by a special method such as optical contact or diffusion bonding, but in this case as well, light transmission may be hindered by damage to the bonding surface. There is sex.

  The present invention has been made in view of the above problems, and includes a laser medium, a saturable absorber as a Q switch element, a resonator composed of the laser medium and the saturable absorber, and passive Q switching including an excitation source. An object of the present invention is to realize an inexpensive configuration capable of shortening a resonator length in order to obtain a high peak power in a semiconductor laser-excited solid-state laser light source using the technology.

  In order to achieve the above object, according to the first aspect of the present invention, a laser medium (10) that emits light when excited and light emitted from the laser medium (10) are incident, and the incident light power is incident. Is larger, the saturable absorber (20), which is transparent when the incident light power exceeds the absorption saturation threshold, the laser medium (10), and the saturable absorber (20) on the resonance optical path. When the saturable absorber (20) is transparent, the light emitted from the laser medium (10) is resonated, and a part of the light is emitted from the exit surface (22) of the saturable absorber (20). And a pump (40) for causing the pumping light for exciting the laser medium (10) to enter the incident surface (11) of the laser medium (10). In the light source, It is a symptom.

  The exit surface (12) of the laser medium (10) and the entrance surface (21) of the saturable absorber (20) are in contact, and the exit surface (12) of the laser medium (10) and the saturable absorber ( 20) The space part (60) comprised by the said recessed part is formed by providing a recessed part in at least one of the entrance plane (21).

  The incident surface (11) of the laser medium (10) is provided with a first coating film (51) that transmits the excitation light and totally reflects the light emitted from the laser medium (10). On the exit surface (22) of the saturable absorber (20), a second coating film (52) is formed in which a part of the light emitted from the laser medium (10) is transmitted and the remaining part is reflected. The light emitted from the laser medium (10) passes through the space (60). The laser light source of the present invention is characterized by these points.

  In the resonator (30) of the present invention, the laser medium (10) and the saturable absorber (20) are brought into contact with each other, and the first and second coatings have the function of a conventional reflecting mirror. Since they are integrated as the films (51, 52), it is possible to realize a configuration in which the resonator length is short, the peak power is higher, and the vibration resistance is improved.

  In the present invention, the contact between the laser medium (10) and the saturable absorber (20) is not the entire surface contact, but the space portion (between the laser medium (10) and the saturable absorber (20)). By providing 60), partial contact is realized at a portion other than the space (60). Then, light is transmitted between the laser medium (10) and the saturable absorber (20) at the space (60).

  As described above, although the laser medium (10) and the saturable absorber (20) have a contact structure, light transmission can be secured in the space (60), and therefore, in a portion other than the space (60). The laser medium (10) and the saturable absorber (20) can be brought into contact with each other and bonded. Therefore, the surface of the part through which light is transmitted is not damaged by the bonding.

  That is, in the laser light source of the present invention, since any method can be adopted as a joining method between the laser medium (10) and the saturable absorber (20), The degree of freedom can be improved.

  Therefore, according to the present invention, a laser medium (10), a saturable absorber (20) as a Q switch element, a resonator (30) composed of the laser medium (10) and the saturable absorber (20), and In the solid-state laser light source pumped by the semiconductor laser using the passive Q switching technology including the pumping source (40), it is possible to realize an inexpensive configuration capable of shortening the resonator length so as to obtain a high peak power.

  Further, in the invention according to claim 2, in the laser light source according to claim 1, the exit surface (12) of the laser medium (10) and the entrance surface (21) of the saturable absorber (20) It is characterized by being bonded and fixed at the contact portion (70).

  According to a third aspect of the present invention, in the laser light source according to the first or second aspect, a guide member (80) for supporting the resonator (30) is provided outside the resonator (30). It is characterized by being.

  According to this, since the laser medium (10) and the saturable absorber (20) integrated as the resonator (30) are supported by the guide member (80), the support becomes stronger and resonance occurs. Since the heat generated in the container (30) can be dissipated through the guide member (80), the heat dissipation can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a semiconductor laser-excited solid-state laser light source 100 using passive Q switching technology according to a first embodiment of the present invention.

  The laser light source 100 according to the present embodiment is roughly composed of a laser medium 10, a saturable absorber 20 as a Q switch element, and a resonator 30 in which the laser medium 10 and the saturable absorber 20 are arranged on a resonance optical path. And an excitation source 40.

  The laser medium 10 emits light when excited. Then, the excitation light L1 from the excitation source 40 is incident on the incident surface 11 of the laser medium 10, whereby the laser medium 10 is excited to the upper level to generate an inversion distribution, and the upper level. With the transition from the lower level to the lower level, the light L2 is emitted from the emission surface 12 side.

  Here, a first coating film 51 is formed on the incident surface 11 of the laser medium 10. The first coating film 51 transmits the excitation light L1 and totally reflects the light L2 emitted from the laser medium 10.

  The saturable absorber 20 functions as a Q switch element. The saturable absorber 20 enters the light L2 emitted from the laser medium 10 from the incident surface 21. The greater the incident light power, the smaller the absorption, and the incident light. The incident light L2 is absorbed when the power is less than or equal to the absorption saturation threshold, but becomes transparent when the incident light power exceeds the absorption saturation threshold.

  Here, a second coating film 52 is formed on the emission surface 22 of the saturable absorber 20. The second coating film 52 transmits a part of the light L2 emitted from the laser medium 10 and reflects the remaining part.

  The first coating film 51 and the second coating film 52 are, for example, multilayer films formed by alternately laminating TaO 2 and SiO 2, and the reflection of the coating films 51 and 52 is changed by changing the number of layers. Characteristics such as rate and transmittance can be adjusted.

  For example, by increasing the number of layers of the first coating film 51 and decreasing the number of layers of the second coating film 52, the above-described characteristics unique to the coating films 51 and 52 can be realized.

  Further, by changing the materials of the first coating film 51 and the second coating film 52, the above-described film characteristics can be realized. For example, the material of the coating films 51 and 52 can be MgF 2 or the like. These coating films 51 and 52 can be formed, for example, by vapor deposition.

  The resonator 30 includes the laser medium 10 and the saturable absorber 20 arranged on the resonance optical path, and resonates the light L2 emitted from the laser medium 10 when the saturable absorber 20 is transparent. A part of the light L2 is emitted from the exit surface 22 of the saturable absorber 20.

  Specifically, in the resonator 30, the first coating film 51 transmits the excitation light L1 output from the excitation source 40, but the light L2 emitted from the excited laser medium 10 has a high reflectance. Reflect.

  Then, the second coating film 52 transmits a part of the power of the light L2 emitted and reached from the excited laser medium 10 and reflects the remaining part. The light L3 transmitted through the second coating film 52 and output to the outside becomes the laser oscillation light L3 output from the laser light source 100.

  Here, as shown in FIG. 1, in the present embodiment, the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20 are in contact with each other, and the incident of the saturable absorber 20 is further performed. A concave portion is provided on the surface 21, and a space portion 60 formed by the concave portion of the incident surface 21 is formed.

  For example, the space 60 is an air layer filled with air. However, the space 60 may be filled with other gas such as nitrogen or rare gas, or may be vacuum. That is, it is only necessary that the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20 are separated from each other via the space portion 60.

  A portion where the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20 are in contact with each other outside the space portion 60, that is, the contact portion 70 is, for example, adhesive bonding, optical contact, Bonding is performed by a method such as diffusion bonding or optical welding.

  The thickness W1 of the space portion 60, that is, the depth W1 of the concave portion forming the space portion 60 is preferably large enough to confirm the space portion 60 between the laser medium 10 and the saturable absorber 20, for example, about 100 μm. . If the depth W1 of the concave portion is excessively increased, the length W2 of the crystal portion must be increased correspondingly, and the resonator length becomes longer.

  The diameter D of the space 60 is preferably larger than the beam diameter D ′ of the excitation light L1, for example, about 2 mm to 4 mm. If it is smaller than this, the excitation light L1 strikes the contact portion 70, and if it is larger, the crystal size and diameter W3 must be increased accordingly.

  As described above, in the present embodiment, in the contact between the laser medium 10 and the saturable absorber 20, a part of the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20 are separated by the space 60. In this case, the contact is performed at the contact portion 70 other than the space portion 60. The light L2 emitted from the laser medium 10 passes through the space 60 and is incident on the saturable absorber 20.

  Further, in the laser medium 10 and the saturable absorber 20 facing each other in the space portion 60, the surface on the laser medium 10 side has a dielectric that totally reflects the excitation light L1 in order to increase the excitation efficiency of the laser medium 10. A body multilayer film (not shown) is coated. On the other hand, the surface on the saturable absorber 20 side in the space 60 is coated with a dielectric multilayer film (not shown) that totally transmits the light L2 emitted from the laser medium 10.

  By coating these dielectric multilayer films, the absorption length of the excitation light L1 can be increased without changing the length of the laser medium 10, so that the absorption efficiency of the excitation light L1 can be improved and the pulse width can be shortened. The output power can be improved. Furthermore, the incidence of the excitation light L1 on the saturable absorber 20 can be suppressed, and the output pulse energy can be increased.

  In the example shown in FIG. 1, the concave portion is provided on the incident surface 21 of the saturable absorber 20, and the space portion 60 is formed by making the incident surface 21 a surface having a concave surface formed in part. On the contrary, the space 60 may be formed by providing a concave portion on the emission surface 12 of the laser medium 10 and making the emission surface 12 a surface with a concave surface formed in part.

  Also in this case, the exit surface 12 of the laser medium 10 and the entrance surface 21 of the saturable absorber 20 can be separated from each other via the space portion 60, and can be separated from the exit surface 12 of the laser medium 10 other than the space portion 60. The contact part 70 with the incident surface 21 of the saturated absorber 20 can be a joint part by an adhesive agent, an optical contact, diffusion bonding (diffusion joining), etc., for example.

  Also in this case, the above-described dielectric multilayer films (not shown) are coated on the surfaces of the laser medium 10 and the saturable absorber 20 facing each other in the space 60.

  In other words, in order to form the space 60, recesses may be provided on both the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20. That is, by providing a recess in at least one of the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20, the space 60 formed by the recess may be formed.

  The excitation source 40 is for making the excitation light L1 for exciting the laser medium 10 incident on the incident surface 11 of the laser medium 10. In this example, the excitation source 40 includes a light source 41 and a condenser lens 42. It is a thing.

  Although not shown, the light source 41 has, for example, a drive circuit and a control circuit, and is driven by a drive current supplied from the drive circuit to output excitation light L1 having a wavelength capable of exciting the laser medium 10. . The condensing lens 42 is an optical system for adjusting and changing the beam size and shape of the excitation light L1.

  The excitation light L1 output from the light source 41 is applied to the laser medium 10 through the condenser lens 42 and the first coating 51. Further, in the light source 41, the control unit controls excitation of the laser medium 10 due to irradiation of the excitation light L <b> 1 output from the light source 41 by controlling the drive circuit. Under the control of the control unit, the light source 41 outputs pulsed excitation light L1 to excite the laser medium 10 in a pulsed manner.

  Although not limited, for example, in the laser light source 100 of the present embodiment, the laser medium 10 is an Nd: YAG crystal, and the saturable absorber 20 is a Cr: YAG crystal. In this case, as the light source 41, a semiconductor laser light source that outputs excitation light L1 having a wavelength of about 808 nm that can excite Nd ions contained in the laser medium 10 to an upper level is used.

  When the excitation light L1 output from the light source 41 enters the laser medium 10, Nd ions contained in the laser medium 10 are excited to the upper level. When the light L2 emitted from the laser medium 10 enters the saturable absorber 20, the Cr ions contained in the saturable absorber 20 are excited to the upper level. The wavelengths of the light L2 and L3 emitted from the laser medium 10 are 1064 nm.

  In the laser light source 100, the excitation light L 1 output from the light source 41 of the excitation source 40 is collected by the condenser lens 42, passes through the first coating 51, and passes from the incident surface 11 of the laser medium 10 to the laser medium. 10 is incident. The excitation light L 1 incident on the laser medium 10 passes through the laser medium 10, is reflected by the reflecting surface 12 of the laser medium 10, and passes through the laser medium 10 again.

  Thus, the laser medium 10 is excited while the excitation light L1 passes through the laser medium 10, and the light L2 is emitted from the laser medium 10 in accordance with the transition from the excited upper level to the lower level. The The light L <b> 2 emitted from the laser medium 10 passes through the space portion 60 and enters the saturable absorber 20 from the incident surface 21 of the saturable absorber 20.

  If the power of the light L2 incident on the saturable absorber 20 is equal to or less than the absorption saturation threshold of the saturable absorber 20, the saturable absorber 20 absorbs the light L2, and thus the Q value of the resonator 30 is small. Laser oscillation is suppressed.

  On the other hand, if the power of the light L2 incident on the saturable absorber 20 exceeds the absorption saturation threshold of the saturable absorber 20, the absorption of the light L2 in the saturable absorber 20 is saturated. 20 becomes transparent, the Q value of the resonator 30 becomes large, and laser oscillation can occur.

  As a result of this laser oscillation, laser light L3 is output to the outside through the second coating film 52 from the exit surface 22 of the saturable absorber 20 which is the output end. Here, a part of the light L2 is transmitted by the second coating film 52 and oscillated as the laser light L3, but the remaining part is reflected and incident on the laser medium 10, and the light resonates.

  Thus, when laser oscillation is started, stimulated emission suddenly occurs in the laser medium 10, and the inversion distribution becomes almost zero, and accordingly, the inversion distribution of the saturable absorber 20 becomes almost zero, and the resonator 30. The Q value of suddenly decreases. Therefore, laser oscillation is completed within a short time. In this way, the laser light source 100 outputs the high-power / short-pulse laser beam L3 to the outside.

  Such a laser light source 100 can be manufactured as follows. A recess for forming the space 60 is formed in at least one of the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20, and the laser medium 10 and the saturable absorber 20 are joined.

  Thereafter, the incident surface 11 of the laser medium 10 and the exit surface 22 of the saturable absorber 20 are polished to parallelize the both surfaces 11 and 22. Then, the first coating film 51 is formed on the incident surface 11 of the laser medium 10 and the second coating film 52 is formed on the emission surface 22 of the saturable absorber 20 by vapor deposition or the like.

  Here, the reflectance of the second coating film 52 is changed according to conditions such as energy to be extracted and pumping light power. For example, in order to obtain a large pulse energy of about several mJ, the reflectance is set to about 50 to 70%, and when a pulse energy of sub-mJ or less is obtained, a larger reflectance is used.

  As described above, the laser light source 100 of the present embodiment receives the laser medium 10 that emits light when excited and the light L2 emitted from the laser medium 10, and the greater the incident light power, the more the light is absorbed. The saturable absorber 20, which is small and transparent when the incident light power exceeds the absorption saturation threshold, the laser medium 10 and the saturable absorber 20 are arranged on the resonance optical path, and the saturable absorber 20 is transparent. For resonating the light L2 emitted from the laser medium 10 and exciting the laser medium 10 with the resonator 30 that emits a part of the light L2 from the emission surface 22 of the saturable absorber 20. A basic structure of a solid-state laser light source for pumping a semiconductor laser using a passive Q switching technique, comprising: a pumping source 40 for causing the pumping light L1 to enter the incident surface 11 of the laser medium 10; And it has a.

  In the present embodiment, the laser light source 100 as a semiconductor laser-excited solid-state laser light source using such a passive Q switching technique has the following unique features.

  The exit surface 12 of the laser medium 10 and the entrance surface 21 of the saturable absorber 20 are in contact with each other, and a recess is provided on at least one of the exit surface 12 of the laser medium 10 and the entrance surface 21 of the saturable absorber 20. Thus, the space portion 60 constituted by the concave portion is formed.

  A first coating film 51 that transmits the excitation light L1 and totally reflects the light L2 emitted from the laser medium 10 is formed on the incident surface 11 of the laser medium 10, and the saturable absorber 20 A second coating film 52 is formed on the emission surface 22 so that a part of the light L2 emitted from the laser medium 10 is transmitted and the remaining part is reflected. The light L2 emitted from the laser medium 10 is a space. It should be able to pass through part 60. According to this embodiment, the laser light source 100 characterized by these points is provided.

  Conventionally, the parts of all of the independent reflector, laser medium, and saturable absorber are parallelized and polished, and then the parallelism between the parts is adjusted by a person. According to this laser light source 100, it is only necessary to perform strict parallelism of only two surfaces, that is, the incident surface 11 of the laser medium 10 on which the coating films 51 and 52 are provided and the exit surface 22 of the saturable absorber 20. Therefore, time and cost can be largely omitted.

  In the present embodiment, the number of parts of the resonator 30 is substantially only two, that is, the laser medium 10 and the saturable absorber 20, and the mechanical accuracy is improved in obtaining the parallelism of the coating surfaces 11 and 22. If this is the case, other adjustments are not necessary, so that the laser light source 100 can be mass-produced.

  Furthermore, according to the present embodiment, the laser medium 10 and the saturable absorber 20 can be integrated by bringing them into contact with each other, so that the resonator length is the sum of the lengths of the laser medium 10 and the saturable absorber 20. In general, the shorter the resonator length, the shorter the pulse width and the greater the peak power.

  In the present embodiment, the resonator length is substantially the same as the length of the crystal constituting the laser medium 10 and the saturable absorber 20, and the required minimum resonator length is sufficient. Can be taken out.

  As described above, in the resonator 30 of the present embodiment, the laser medium 10 and the saturable absorber 20 are integrated by bringing them into contact with each other, and the first and second coating films have functions of a conventional reflecting mirror. Since they are integrated as 51 and 52, it is possible to realize a configuration in which the resonator length is short, the peak power is higher, and the vibration resistance is improved.

  In addition, as described above, when the laser medium and the saturable absorber are brought into contact with each other in order to shorten the resonator length, if both of them are directly joined, the joining method is restricted and damage to the joining surface cannot be avoided. .

  In that respect, in the present embodiment, the contact between the laser medium 10 and the saturable absorber 20 is not the entire surface contact, but by providing the space 60 between the laser medium 10 and the saturable absorber 20, This is realized as a partial contact at a portion other than the space 60. Then, light is transmitted between the laser medium 10 and the saturable absorber 20 at the space 60.

  As described above, although the laser medium 10 and the saturable absorber 20 have a contact structure, light transmission can be ensured in the space portion 60, so that the laser medium 10 and the saturable absorber are located in a portion other than the space portion 60. 20 can be brought into contact with each other. Therefore, the surface of the part through which light is transmitted is not damaged by the bonding.

  That is, in the laser light source 100 of the present embodiment, an arbitrary method can be adopted as a bonding method between the laser medium 10 and the saturable absorber 20, and thus the degree of freedom of the bonding method. Can be improved.

  Therefore, according to the present embodiment, the laser medium 10, the saturable absorber 20 as a Q switch element, the resonator 30 including the laser medium 10 and the saturable absorber 20, and the passive Q switching including the excitation source 40. In the solid-state laser light source 100 of the semiconductor laser excitation using the technology, it is possible to realize an inexpensive configuration capable of shortening the resonator length so as to obtain a high peak power.

  Further, in the laser light source 100 of this embodiment, the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20 can be bonded and fixed at the contact portion 70. One. That is, the contact portion 70 can be bonded via an adhesive, and an inexpensive bonding configuration can be realized by using such an adhesive.

(Second Embodiment)
FIG. 2 is a schematic cross-sectional view showing the main part of a solid-state laser light source 200 of semiconductor laser excitation using passive Q switching technology according to the second embodiment of the present invention.

  As shown in FIG. 2, the laser light source 200 of the present embodiment is similar to that shown in FIG. 1, the laser medium 10, the saturable absorber 20 as a Q switch element, the laser medium 10 and the saturable light source. It has a basic configuration of a solid-state laser light source pumped by a semiconductor laser using a passive Q switching technique that includes a resonator 30 including an absorber 20 and the pumping source (not shown in FIG. 2).

  Furthermore, also in the laser light source 200 of the present embodiment, the exit surface 12 of the laser medium 10 and the entrance surface 21 of the saturable absorber 20 are in contact with each other, and the exit surface 12 of the laser medium 10 and the saturable absorber 20 The first coating film is formed on the incident surface 11 of the laser medium 10 and the exit surface 22 of the saturable absorber 20 by forming a recess in at least one of the incident surfaces 21. 51, the second coating film 52 is formed, and the light L2 emitted from the laser medium 10 passes through the space 60 as in the above embodiment.

  Therefore, similarly to the above-described embodiment, the laser light source 200 of the present embodiment having these configurations can also realize an inexpensive configuration that can shorten the resonator length to obtain a high peak power.

  Further, as shown in FIG. 2, in the laser light source 200 of the present embodiment, a guide member 80 that supports the resonator 30 is provided outside the resonator 30.

  The material of the guide member 80 is not particularly limited as long as it has a strength capable of supporting the laser medium 10 and the saturable absorber 20 constituting the resonator 30. However, the material of the guide member 80 is not particularly limited. And what has the thermal expansion coefficient similar to the saturable absorber 20 is preferable.

  Further, the shape of the guide member 80 is not particularly limited as long as it is located at the outer peripheral portion of the laser medium 10 and the saturable absorber 20, and can support them. For example, as the guide member 80, Any structure can be used as long as it can have a cylindrical shape and the resonator 30 can be disposed in the hollow portion.

  According to the laser light source 200 of the present embodiment, since the laser medium 10 and the saturable absorber 20 integrated as the resonator 30 are supported by the guide member 80, the support becomes stronger and the resonator Since the heat generated at 30, that is, the heat generated from the laser medium 10 and the saturable absorber 20 can be radiated through the guide member 80, the heat dissipation can be improved.

  That is, the guide member 80 functions as a support member that supports the laser medium 10 and the saturable absorber 20 and also functions as a heat dissipation member. In order to improve the heat dissipation characteristics, a member such as an adhesive having excellent thermal conductivity may be interposed between the laser medium 10 and the saturable absorber 20 and the guide member 80.

  Further, in the present embodiment, at the contact portion 70 between the emission surface 12 of the laser medium 10 and the incident surface 21 of the saturable absorber 20, the both surfaces 12 and 21 are connected via an adhesive member 90 such as an adhesive or solder. In this case, a contrivance is made to prevent the adhesive member 90 from flowing into the space 60 which is a path of light.

  That is, in this embodiment, as shown in FIG. 2, a concave portion 71 as an adhesive member application portion is provided on the outer peripheral portion of the contact portion 70, and the adhesive member 90 is poured into this portion for bonding. Yes.

  Thereby, it is possible to prevent the adhesive member 90 from flowing into the space 60. Further, by using the adhesive member 90, the guide member 80 and the resonator 30 can be joined, and the vibration resistance can be further improved.

(Other embodiments)
In addition, about the laser medium, a saturable absorber, and the 1st and 2nd coating film, the example of the material shown to the said embodiment is a specific example to the last, and is not limited to the above-mentioned thing.

  In short, the present invention relates to a laser medium, a saturable absorber as a Q-switch element, a resonator composed of the laser medium and the saturable absorber, and a semiconductor laser-pumped solid using passive Q-switching technology including a pump source. As long as it is a laser light source, it is applicable also to laser light sources other than the said embodiment.

  In the laser light source according to the present invention, the exit surface of the laser medium and the entrance surface of the saturable absorber are brought into contact with each other, and a recess is formed on at least one of the exit surface of the laser medium and the entrance surface of the saturable absorber. By providing, a space portion formed by the concave portion is formed, and the first coating film and the second coating film 52 are formed on the incident surface of the laser medium and the exit surface of the saturable absorber, respectively. The main part is that the light emitted from the laser medium passes through the space, and the design of the other parts can be changed as appropriate.

It is a schematic sectional drawing of the solid-state laser light source of the semiconductor laser excitation using the passive Q switching technique which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the solid-state laser light source of the semiconductor laser excitation using the passive Q switching technique which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laser medium, 11 ... Incident surface of laser medium, 12 ... Outgoing surface of laser medium,
20 ... saturable absorber, 21 ... incident surface of saturable absorber, 22 ... exit surface of saturable absorber,
30 ... resonator, 40 ... excitation source,
51 ... 1st coating film, 52 ... 2nd coating film, 60 ... space part,
70 ... contact part, 80 ... guide member,
L1 ... excitation light, L2 ... light emitted from the laser medium.

Claims (3)

A laser medium (10) that emits light when excited;
The saturable absorber (20) is incident when the light emitted from the laser medium (10) is incident, the absorption is smaller as the incident light power is larger and the incident light power exceeds the absorption saturation threshold. When,
The laser medium (10) and the saturable absorber (20) are arranged on a resonance optical path, and the light emitted from the laser medium (10) is resonated when the saturable absorber (20) is transparent. And a resonator (30) for emitting a part of the light from the exit surface (22) of the saturable absorber (20),
In a laser light source comprising: an excitation source (40) for causing excitation light for exciting the laser medium (10) to enter an incident surface (11) of the laser medium (10),
The exit surface (12) of the laser medium (10) and the entrance surface (21) of the saturable absorber (20) are in contact;
By providing a recess in at least one of the exit surface (12) of the laser medium (10) and the entrance surface (21) of the saturable absorber (20), the space (60) configured by the recess is formed. Formed,
The incident surface (11) of the laser medium (10) is formed with a first coating film (51) that transmits the excitation light and totally reflects the light emitted from the laser medium (10). ,
On the exit surface (22) of the saturable absorber (20), a second coating film (52) is formed in which a part of the light emitted from the laser medium (10) is transmitted and the remaining part is reflected. And
The laser light source characterized in that light emitted from the laser medium (10) passes through the space (60). The exit surface (12) of the laser medium (10) and the entrance surface (21) of the saturable absorber (20) are bonded and fixed at a contact portion (70) thereof. Item 2. The laser light source according to Item 1. The laser light source according to claim 1 or 2, wherein a guide member (80) for supporting the resonator (30) is provided outside the resonator (30).

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