JP2501908B2 - Laser oscillator - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

 The present invention relates to a laser oscillator.

[Prior art]

It is generally known that the shape of an output laser beam from a laser oscillator changes depending on the shape of a mirror forming an optical resonator or a spatial filter arranged in the laser oscillator. Furthermore, by inserting an electro-optic crystal or an acousto-optic element into the laser oscillator, the laser oscillation light is modulated,
It is known that when the laser oscillation light is modulated by directly modulating the excitation source, the output laser beam has a disordered shape. In particular, when the output light from the laser oscillator is incident on the nonlinear optical crystal to obtain the wavelength-converted light, the variation of the conversion efficiency due to the inhomogeneity of the nonlinear optical crystal and the wavelength conversion efficiency being proportional to the incident light density It is known that the intensity distribution of the wavelength-converted light is such that the original intensity distribution of the incident light is more emphasized, resulting in a more disturbed output laser beam shape.

[Problems to be Solved by the Invention]

Conventionally, the laser beam shape shaping method that has been performed to shape the disorder of the output laser beam shape as described above has been performed by the mirror for the optical resonator or the space filter having the fixed shape. There was a problem that precise or flexible beam shaping corresponding to the shape was difficult. In particular, in a solid-state laser such as Nd; YAG laser, individual laser rods or excitation lamps, there is a large variation in characteristics, shaping of the irregular intensity distribution due to such variation, in the conventional method described above. There was a problem that it was impossible. The present invention has been made in view of the above problems, and an object thereof is to provide a laser oscillator capable of freely shaping a disturbed output laser beam shape and freely adjusting the intensity distribution of output light. And

[Means for Solving the Problems]

The present invention includes a laser medium, an excitation source, and an optical resonator, and a total reflection mirror in the optical resonator has a reflective spatial light modulation capable of arbitrarily adjusting a reflectance spatial distribution or an optical phase change spatial distribution. The above-mentioned object is achieved by a laser oscillator characterized by being configured as a container. The second invention includes a laser medium, an excitation source, and an optical resonator, and the transmittance spatial distribution or the light is distributed at an arbitrary position in the optical path between the total reflection mirror and the output side of the output mirror in the optical resonator. The laser oscillator is characterized by arranging a transmissive spatial light modulator whose phase change spatial distribution can be arbitrarily adjusted, thereby achieving the above object. Furthermore, a third aspect of the present invention includes a laser medium, an excitation source, and an optical resonator, and a total reflection mirror in the optical resonator has a reflective space in which a reflectance spatial distribution or an optical phase change spatial distribution can be arbitrarily adjusted. A transmission type space that can be used as an optical modulator and can arbitrarily adjust the transmittance spatial distribution or the optical phase change spatial distribution at an arbitrary position in the optical path between the total reflection mirror and the output side of the output mirror in the optical resonator. The laser oscillator is characterized in that an optical modulator is arranged to achieve the above object. In the above first, second or third invention, the above object is achieved by providing a feedback back system for guiding a part of the laser light emitted from the output mirror in the optical resonator as the writing light of the spatial light modulator. To achieve. Further, in the first, second, or third invention, an imaging device that uses a part of the laser light emitted from the output mirror in the optical resonator as a video signal, and the spatial light by processing the video signal. An image processing device that outputs an image signal as writing light of the modulator to the spatial light modulator,
The above object is achieved by constructing the feed back system including the above. Further, in the first, second or third invention, the above object is achieved by providing an image signal generating device for generating an image signal as writing light of the spatial light modulator.

[Action]

The first invention of this application comprises a total reflection mirror in an optical resonator by a reflection-type spatial light modulator capable of arbitrarily adjusting a reflectance spatial distribution or an optical phase change spatial distribution. A transmissive spatial light modulator capable of arbitrarily adjusting the transmittance spatial distribution or the optical phase change spatial distribution is arranged at an arbitrary position in the optical path between the total reflection mirror and the output side of the output mirror in the resonator, and further, In the third invention, the total reflection mirror is the reflection type spatial light modulator as described above, and the transmission type spatial light modulator is arranged at an arbitrary position in the optical path between the total reflection mirror and the output mirror output side. By adjusting the reflectance spatial distribution or the optical phase change spatial distribution according to the output laser beam shape, the laser beam shape can be freely shaped.

【Example】

An embodiment of the first invention will be described below. The first invention, as shown in FIG.
And an excitation source 12, and an optical resonator comprising a total reflection mirror 14 and an output mirror 16, the total reflection mirror 14
Is a reflection type spatial light modulator capable of arbitrarily adjusting the reflectance spatial distribution or the optical phase change spatial distribution. Although there are various types of reflection type spatial light modulators as an optical parallel processing device, in the first embodiment of the first invention, as shown in FIG. 2, the reflectance spatial distribution type spatial light modulator 14A.
That is, the birefringence effect of the electro-optic crystal 20 is utilized. In FIG. 2, reference numeral 22 is a laser medium 10 and an electro-optic crystal.
Polarizer disposed between 20 and 24 and 26 are electro-optic crystals
Reference numeral 28 denotes a transparent electrode and an antireflection film formed on the surface of the polarizer 22 side, and reference numeral 28 denotes a dielectric multilayer film mirror formed on the opposite side of the electro-optic crystal 20 from the transparent electrode. In the electro-optic crystal 20, the plane of polarization is rotated according to the birefringence effect based on the anisotropy of the refractive index in the crystal, and after being reflected by the dielectric multilayer film mirror 28, the same polarizer 22 is again provided. The intensity modulation occurs when the light passes through, and thereby the spatial intensity modulation is performed. That is, the refractive index difference Δn in the x and y axis directions depending on the applied voltage.
(X, y) ≡n _x (x, y) −n _y (x, y) is used, and an electric charge or potential space distribution is generated on the surface of the dielectric multilayer mirror 28 by a writing signal. If given, the refractive index difference spatial distribution Δn (x, x, corresponding to the difference V (x, y) −V ₀ with the constant potential V ₀ applied to the transparent electrode 24 according to the surface potential distribution V (x, y). y) occurs. When laser light is incident on the electro-optic crystal 20 from the transparent electrode 24 side through a polarizer 22 having a polarization axis in the 45 ° direction with the x and y axes of the crystal, linear polarization x and y axis polarization plane components are generated. By being reflected by the dielectric multilayer film mirror 28 and reciprocating through the electro-optic crystal 20, a phase difference corresponding to Δn (x, y) is generated, which causes rotation of the plane of polarization. Light emitted from the electro-optic crystal 20 and passing through the polarizer 22 again is converted into intensity change according to the rotation of the plane of polarization. That is, the reflectance spatial distribution is effectively obtained according to the potential spatial distribution V (x, y) of the dielectric multilayer mirror 28. Next, a second embodiment of the first invention shown in FIG. 3 will be described. The second embodiment uses a spatial light modulator 14B of the Fabry-Perot interference effect type. This spatial light modulator 1
4B is an optical path length (n × d;
A transparent electrode 32 and a dielectric mirror are formed on the surface of the laser medium 10 side using an optical material 30 that causes a change Δ (nd) in refractive index × thickness
34 is laminated in this order, and the dielectric mirror 36 is provided on the other surface.
Are laminated. Here, the dielectric mirrors 34 and 36 are partial reflection mirrors whose reflectance R is a value slightly lower than 100%, and are considered as Fabry-Perot resonators in which the optical material 30 is an etalon (spacer) layer. Alternatively, as the optical material 30, an electro-optical material whose refractive index n in the direction perpendicular to the applied voltage changes according to the voltage, or a thickness d
There is a translucent piezoelectric material (piezoelectric polymer, piezoelectric ceramics, etc.) that changes according to the voltage. In this embodiment, when a charge or potential space distribution is given to the surface of the dielectric mirror 36, a constant voltage V ₀ applied to the transparent electrode 32 which is exposed according to the surface potential distribution V (x, y). Difference V
(X, y) −V ₀ optical path length change Δ (nd) (x,
y) occurs. When laser light having a wavelength λ is incident on the optical material 30 from the transparent electrode 32 side, the intensity of reflected light changes due to optical interference according to the optical path length nd. That is, the reflectance spatial distribution can be effectively obtained according to the potential spatial distribution V (x, y) of the dielectric mirror 36. Next, a third embodiment shown in FIG. 4 will be described. This third embodiment uses a spatial light modulator 14C of the equiphase surface spatial distribution type, and includes an electro-optic material 38 in which the refractive index n in the applied voltage direction changes according to an applied voltage, and the electro-optical material 38. The transparent electrode 40 and the antireflection film 42, which are laminated in this order on the surface of the optical material 38 on the laser medium 10 side, and the electro-optical material 38.
, A dielectric mirror formed on the surface opposite to the transparent electrode 40.
It is composed of 44 and. In this embodiment, when an electric charge or electric potential distribution is given to the surface of the dielectric mirror 44, the difference V from the constant voltage V ₀ applied to the transparent electrode 40 depends on the surface electric potential distribution V (x, y). (X, y) -V ₀
A refractive index spatial distribution n (x, y) corresponding to When a laser beam is incident on the electro-optical material 38 from the transparent electrode 40 side, a phase change occurs according to n (x, y), and the equiphase surface of the laser beam is incident before the electro-optical material 38 enters. And it will change after emission. Such a change in the equiphase surface becomes polarized light that bends the traveling direction of light, as in the case of an optical lens. Next, a description will be given of an embodiment in the case where a charge or potential distribution is given to the surfaces of the dielectric mirrors 28, 36 and 44 in the above reflection type spatial light modulators 14A to 14C. This includes writing by an optical signal, that is, optical writing, writing by an electric signal, and electric writing. FIG. 5 shows an embodiment in the case of optical writing using a photoconductor. In this embodiment, the dielectric mirror 46 (the dielectric mirror 2
A light-shielding layer 48, a photoconductor 50, and a transparent electrode 52 are laminated in this order on the outer side of those corresponding to 8, 36, 44, and the same hereinafter. The photoconductor 50 has a property of lowering the electric resistance of the light-irradiated portion, for example, Si, amorphous Si, amorphous Se, CdS or the like is formed on the derivative mirror 46, the light-shielding layer. 48 is composed of a CdTe film or the like. In this embodiment, when a constant potential V ₁ is applied to the transparent electrode 52 and an optical writing image is incident from the transparent electrode 52 side, a spatial potential distribution corresponding to the pattern is generated on the surface of the dielectric mirror 46. . Here, in the light shielding layer 48, a part of the laser light is a dielectric mirror.
It is for preventing the light from passing through 46 and entering the photoconductor 50, and is not necessarily provided as long as the amount of transmitted light is negligible. Next, the embodiment shown in FIG. 6 will be described. In this example, a photocathode is used.
After the optical writing image is converted into an electronic image by 54, a microchannel plate (MCP) 58 is passed through an electronic lens system 56.
The electric charge is multiplied by a factor of several thousand to be accumulated as a charge image on the surface of the dielectric mirror 46. Reference numeral 60 in FIG. 6 denotes a secondary electron collecting electrode mesh, which is a dielectric mirror.
46 By utilizing the secondary electron emission effect of the surface material, the charge image can be written and erased. The space between the dielectric mirror 46 and the photocathode 54 is a vacuum. Next, the case of electric writing by the electron beam shown in FIG. 7 will be described. In this embodiment, an electron beam from an electron gun 62 scans the dielectric mirror 46 by an electron lens system 64 to write and store a charge image. Similar to the embodiment shown in FIG. 6, in this embodiment also, the secondary electron collecting electrode mesh 60 is arranged between the electron lens system 64 and the dielectric mirror 46 to write a charge image, It is possible to erase. The space between the electron gun 62 and the dielectric mirror 46 is a vacuum. Next, the case of electrical writing by the CCD (charge coupled device) shown in FIG. 8 will be described. In this embodiment, the light shielding layer 48,
A structure in which a CCD readout structure 66 and a CCD surface channel parallel structure 68 are laminated in this order, and the input time series electric signal is converted into a two-dimensional information frame and stored as a charge packet in the CCD array. Is. Next, an embodiment in which the feed back system of the first invention shown in FIG. 9 is provided will be described. In this embodiment, the laser medium 10 is an Nd; YAG rod, the output mirror 16 has a reflectivity R = 10%, and the reflective spatial light modulator is the spatial light modulator shown in FIG.
Further, 14C is used as the writing means, which is provided with the photocathode 54, the electron lens system 56, the MCP 58, and the secondary electron collecting electrode mesh 60 as shown in FIG. On the output side, a partially reflected beam splitter with a reflectance of 2%
70 is provided, and a feedback back system 72 including mirrors 72A, 72B and 72C for guiding a part of the output laser light reflected from the light guide 70 to the photocathode 54 is arranged. Here, a LiNbO ₃ crystal is used as the electro-optic material 38, and the dielectric mirror 44 has a reflectance of 100%. Further, the Nd; YAG rod, which is the laser medium 10, has both ends of the rod machined at the Brewster angle θ. In this embodiment, the laser light from the laser medium 10 reciprocates through the spatial light modulator 14C, and then becomes the elliptically polarized light accompanying the rotation of the plane of polarization as described above, and is the laser medium 10.
By the action of the polarizer on the end face of the Nd; YAG rod, it is converted into intensity-modulated linearly polarized light. The laser light emitted from the output mirror 16 is the laser medium.
The intensity distribution of the output pattern becomes non-uniform due to non-uniform refractive index within 10, non-uniform Nb ion distribution, non-uniform resonator mirror, and the like. Furthermore, as shown by the chain double-dashed line in FIG.
When wavelength-converted light is obtained through a nonlinear optical crystal 74 such as NbO ₃ , KTP or BBO, since the wavelength conversion efficiency is proportional to the incident light density, the non-uniformity in the intensity distribution of the converted light is due to the Nd; YAG laser light. It becomes more remarkable than In this embodiment, a part of the output light from the output mirror 16 or the converted light from the non-linear optical crystal 74 is taken out by the beam splitter 70, and the feedback surface 72 is used as the optical writing surface of the spatial light modulator 14C. The feedback strikes 54. In this way, the optical writing section is connected to the photocathode 54 and the MCP 58.
Therefore, the method for writing a charge image on the dielectric mirror 44 can be coped with by changing the settings of the mesh potential and the crystal rear surface potential. For example, by generating a charge space distribution having a reflectance distribution opposite to that of the incident light intensity distribution on the photocathode 54, or by performing threshold processing, the incident light intensity distribution below a certain value is cut and the light intensity above the threshold is cut. A charge space distribution or reflectance distribution corresponding to the pattern can be created. Therefore, the spatial light modulator 14C can be operated so that the non-uniformity of the intensity distribution of the laser light or the converted light is corrected. In this embodiment, the disordered output light pattern of the conventional Nd; YAG laser, as shown in FIG. 10 (A), is shown in FIG. 2 (B) according to this embodiment. It was possible to obtain a uniform light intensity distribution. Here, by using a difflectron or the like as the electronic lens system 56 of the writing unit in the spatial light modulator 14C, the charge image can be enlarged, reduced, rotated, or moved in parallel, and various preprocessings can be executed. Further, it is also possible to switch the laser oscillation by temporally changing the reflectance of the voltage applied to the back surface of the spatial light modulator 14C by binary switching operation while accumulating the charge image. That is, it can also be operated as a Q switch. In the embodiment shown in FIG. 9, a Brewster cut YAG rod having a polarization effect was also used as the laser medium 10. This is because another polarization element is inserted in the resonator without the Brewster cut. May be. Next, the embodiment shown in FIG. 11 will be described. In this embodiment, an electric writing type spatial light modulator 14C for generating an equiphase spatial distribution is used, and an input signal to the writing section uses an image signal from the image signal generating device 76. . The writing section in this embodiment is the electron gun 62, the electron lens system 64, and the secondary electron collecting electrode mesh 60 shown in FIG.
Is used. The other structure is the same as that of the embodiment shown in FIG. 9 except for the feed back system 72. Therefore, the same parts as those in FIG. The Nd; YAG rod as the laser medium 10 is not subjected to the Brewster cut. In this embodiment, a refractive index spatial distribution is generated in the electro-optical material 38 according to the charge distribution on the surface of the dielectric mirror 44 and the voltage applied to the transparent electrode 40. This refractive index distribution causes the phase distribution of the laser light wavefront, and the deformation of the equiphase surface leads to optical polarization as in the case of the optical lens. Therefore, the curvature radius spatial distribution of the total reflection mirror is formed. Similarly to the above, the spatial light modulator 14C corrects the phase change and the optical path shift due to the nonuniformity of the refractive index in the optical system including the laser medium 10, the optical resonator 18, or the wavelength conversion nonlinear optical crystal 74. . As an electrical writing signal for this correction, an image signal for correction is output from the image signal generation device 76 to the electron gun 62 and the electronic lens 64 in accordance with the phase change and the deviation of the optical path due to the nonuniformity of the refractive index. . In this case, the image signal is stored in the image signal generation device 76 in advance according to the type of the laser medium 10, the characteristics of the nonlinear optical crystal 74, and the like. In this embodiment as well, similar to the embodiment shown in FIG. 9, a part of the output light from the output mirror 16 or the converted light from the nonlinear optical crystal 74 is converted into a beam splitter.
The image signal may be taken out at 70 and used to output the image signal for correction from the image signal generating device 76. That is, a part of the laser output light is branched by the beam splitter 70, this is imaged by the television camera 78, accumulated in the frame memory 80, etc., and the pattern thereof is generated by the image signal generation device.
Appropriate processing is performed at 76, and it is used as a write signal for the spatial light modulator 14C. FIG. 12A shows the intensity distribution in the laser beam when the output laser pattern is imaged by the television camera 78 using the beam splitter 70. By modifying the pattern shown in FIG. 12 (A),
When an electric signal corresponding to the charge distribution as shown in FIG. 12B is inputted as an image signal from the image signal generating device 76 to the spatial light modulator as a write signal, it is corrected by this. The output laser beam pattern is shown in Fig. 12 (C).
It became as shown in. Although each of the embodiments described above is for the case of single wavelength oscillation laser light, the present invention is naturally applicable to the cases of multiwavelength simultaneous oscillation laser and wide band wavelength oscillation laser. In this case, the characteristics different from those of the above-mentioned embodiment are exhibited. That is, a phase change Δφ occurs with the refractive index change Δn of the electro-optic crystal, and in the case of a reflective spatial light modulator, the following wavelength dependence occurs. Δφ (λ) = 4πΔnd / λ−2mπ (d: crystal thickness, m: integer, 0 ≦ Δφ <2π) Therefore, even if different wavelengths are used, Δn (λ ) Can have the same or very different values. Therefore, for example, like a He-Cd metal vapor laser,
In the case of a laser that simultaneously oscillates three colors of blue, green, and red, the laser output pattern can also be deformed, and the intensity ratio of the three colors can be arbitrarily adjusted to generate a composite color. Further, in the case of a wide band oscillation laser such as a Dye laser or a Ti: Al ₂ O ₃ laser, it is possible to function as an optical laser by oscillating only a part of a narrow spectrum of a wide spectrum. Next, the principle of the second invention will be described with reference to FIG. The second invention is a laser oscillator including a laser medium 10, an excitation source 12, and an optical resonator including a total reflection mirror 14 and an output mirror 16, and the total reflection mirror 14 outputs the output mirror 16. A transmissive spatial light modulator 82 capable of arbitrarily adjusting the transmittance spatial distribution or the optical phase change spatial distribution is arranged at an arbitrary position in the optical path between the two sides. FIG. 13 (A) shows a transmission type spatial light modulator 82 arranged between the total reflection mirror 14 and the laser medium 10, and FIG. 13 (B).
Is a transmissive spatial light modulator 82 with a laser medium 10 and an output mirror 16
FIG. 13C, which is disposed between the two, is a transmission type spatial light modulator 82 disposed on the output side of the output mirror 16. Further, FIG. 13D shows the output mirror itself constituted by a transmission type spatial light modulator 82. The first embodiment of the transmissive spatial light modulator 82 is as follows.
There is a spatial distribution type of transmittance utilizing the birefringence effect shown in Fig. 14. This is because an antireflection film 84 is provided in place of the dielectric multilayer mirror 28 in the spatial light modulator 14A shown in FIG. 2 and a charge or potential space distribution is given to the surface of the antireflection film 84. It is a thing. The operation of this transmission type spatial light modulator 82A is the same as that of the reflectance spatial distribution type spatial light modulator 14A in FIG. 2 except for the difference in reflection and transmission, and therefore the same parts are designated by the same reference numerals. The description is omitted. The transmissive spatial light modulator 82A according to this embodiment can be used in the arrangements of FIGS. 13A to 13C, but FIG.
It cannot be used as the output mirror shown in. The transmissive spatial light modulator 82B of the embodiment shown in FIG.
Can also be used as an output mirror. This transmissive spatial light modulator 82B is shown in FIG.
It has substantially the same configuration as the reflective spatial light modulator 14B utilizing the Fabry-Perot interference effect. Since the other construction is the same as that of the embodiment shown in FIG. 3, the description thereof will be omitted by giving the same reference numerals thereto. FIG. 16 shows the reflection type spatial light modulator 14 shown in FIG.
This is a transmission type spatial light modulator 82C which corresponds to C and has an antireflection film 88 in place of the dielectric mirror 44 in the embodiment of FIG. Also in this embodiment, the difference is that the embodiment of FIG. 4 is a reflection but a transmission, and the same parts as those of the embodiment of FIG. 4 are denoted by the same reference numerals. Shall be omitted. However, in the spatial light modulator 82C of the equal phase surface spatial distribution type, the equal phase surface is formed on the exit side of the antireflection film 88 as shown in FIG. Next, the antireflection film 8 of the transmissive spatial light modulators 82A to 88C.
4. An embodiment for giving a charge or potential distribution to the dielectric mirror 86B or the antireflection film 88 will be described. The embodiment shown in FIG. 17 corresponds to the configuration of the embodiment shown in FIG. 6 for the light transmission type, and is provided with a photocathode 54, an electron lens system 56 and an MCP 58, which are arranged on the electro-optic material side. With respect to the optical axis of the laser light that passes through the surface (corresponding to the antireflection films 84, 88 or the dielectric mirror 86B) 90, the laser light is obliquely arranged so as not to interfere with the laser light. . In this embodiment, a secondary electron collecting electrode ring 92 is provided instead of the secondary electron collecting electrode mesh 60 in the embodiment shown in FIG. In the case of this embodiment as well, except for the difference in reflection and transmission, the construction and operation are the same as in the embodiment of FIG. Next, the embodiment shown in FIG. 18 will be described. In this embodiment, electric writing is performed by an electron beam, and the reflection type in the embodiment of FIG. 7 is applied to a transmission type. Also in this embodiment, similarly to the embodiment of FIG. 17, the electron gun 62 and the electron lens system 64 are offset obliquely from the central optical axis of the laser light passing through the electro-optic material side surface 90, and the laser light It is arranged so as not to interfere with. Also in this embodiment, a secondary electron collecting electrode ring 92 is provided instead of the secondary electron collecting electrode mesh. The operation is also the same as that of the embodiment shown in FIG. 7 except for the difference between reflection and transmission, and therefore the explanation is omitted. Next, an embodiment shown in FIG. 19 provided with a sweep back system will be described. This embodiment is a transmissive embodiment using the reflective spatial light modulator shown in FIG.
The first is a spatial light modulator 82C with an equiphase surface spatial distribution shown in the figure.
The photocathode shown in FIG. 7 is combined with a writing means for performing optical writing, and the total reflection mirror 14 is used. Since the other structure is the same as that of FIG. 9, the description thereof will be omitted by giving the same reference numerals. Also, the operation is the same except for the difference between reflection and transmission, and thus the description is omitted. Even in the case of this transmission type, as in the case of the reflection type,
Although the output light pattern in the laser medium 10 is not uniform as shown in FIG. 20 (A), a part of the output light is fed back by the feedback back system 72, so that the output light pattern is not uniform. Was corrected, and as a result, the output light was uniformly corrected as shown in FIG. 20 (B). Next, the embodiment shown in FIG. 21 will be described. This embodiment is a transmissive spatial light modulator shown in FIG. 16 in which the embodiment of FIG. 11 is made transmissive.
82C and the writing means using the electron gun 62 shown in FIG. 18 are combined, and further the total reflection mirror 14 is used. Since the other structure is the same as that of the embodiment shown in FIG. 11, the same parts are designated by the same reference numerals and the description thereof will be omitted. Also, the operation is the same as that of the embodiment of FIG. 11 except that the embodiment of FIG. 11 is reflection, whereas the embodiment of FIG. 11 is transmission. . Next, the third invention shown in FIG. 22 will be described. This third invention is directed to a reflection type spatial light modulator 14 as a total reflection mirror and an output mirror from the reflection type spatial light modulator 14.
In the middle of the optical path between the 16 output sides, a transmissive spatial light modulator 82
Is arranged. 22 (A) shows a transmission type spatial light modulator 82 arranged between the total reflection mirror 14 and the laser medium 10, and FIG. 22 (B).
Is a transmissive spatial light modulator 82 with a laser medium 10 and an output mirror 16
22C, the output mirror itself is composed of a transmissive spatial light modulator 82, and FIG. 22D shows the transmissive spatial light modulator 82 of the output mirror 16. It is arranged on the exit side. When a transmissive spatial light modulator is arranged instead of the output mirror, the transmissive spatial light modulator 82B shown in FIG. 15 must be used. In the embodiment of the third invention, both the reflection type spatial light modulator as the total reflection mirror and the transmission type spatial light modulator 82 arranged on the optical path between the total reflection mirror and the output side position of the output mirror. Is used, it is possible to more strongly correct the intensity distribution of the laser output light.

【The invention's effect】

Since the present invention is configured as described above, it has an excellent effect that the nonuniformity of the intensity distribution of the laser output light can be arbitrarily corrected or adjusted to an arbitrary distribution.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic construction of the first invention, and FIG.
FIG. 4 to FIG. 4 are sectional views showing first to third embodiments of the spatial light modulator in the first invention, and FIGS. 5 to 8 show a dielectric mirror of the spatial light modulator in the first invention. Cross sectional views showing first to fourth embodiments of the writing means, FIG. 9 is a schematic cross sectional view showing an embodiment in which a feedback system of the first invention is provided, and FIG. 10 is correction of an output laser beam in the same embodiment. FIG. 11 is a diagram showing a state before and after correction, FIG. 11 is a schematic sectional view showing an embodiment using an image signal generating device of the first invention, and FIG. 12 is a correction state of an output laser beam of the same embodiment. FIG. 13 is a block diagram showing the basic structure of the second invention, and FIGS.
FIG. 16 is a cross-sectional view showing first to third embodiments of a transmissive spatial light modulator according to the second invention, and FIGS. 17 and 18 are first and second writing means for writing into the spatial light modulator according to the second invention. FIG. 19 is a sectional view showing a second embodiment, FIG. 19 is a schematic sectional view showing an embodiment of the second invention in which a feedback system is provided, and FIG. FIG. 21 is a schematic sectional view showing an embodiment using the image signal generating device of the second invention, and FIG. 22 is a block diagram showing the configuration of the third invention. 10 ... Laser medium, 2 ... Excitation source, 14 ... Total reflection mirror (reflection type spatial light modulator), 14A ... Reflectance spatial distribution type spatial light modulator, 14B, 14C ... Spatial light modulator, 72 …… Fed back system, 74 …… Nonlinear optical crystal, 76 …… Image signal generator, 78 …… TV camera, 80 …… Frame memory,
82, 82A, 82B, 82C ... Transmissive spatial light modulator.

Claims (12)

(57) [Claims] 1. A reflective spatial light including a laser medium, an excitation source, and an optical resonator, wherein a total reflection mirror in the optical resonator is capable of arbitrarily adjusting a reflectance spatial distribution or an optical phase change spatial distribution. A laser oscillator characterized by being used as a modulator. 2. A laser oscillator according to claim 1, further comprising a feedback system for guiding a part of laser light emitted from an output mirror in the optical resonator as writing light for the spatial light modulator. 3. The image pickup device according to claim 2, wherein a part of the laser light emitted from the output mirror in the optical resonator is used as a video signal, and the video signal is processed to write in the spatial light modulator. A laser oscillator, comprising: an image processing device that outputs an image signal as light and outputs the image signal to the spatial light modulator. 4. The laser oscillator according to claim 1, further comprising an image signal generation device for generating an image signal as writing light for the spatial light modulator. 5. A laser medium, an excitation source, and an optical resonator, wherein the transmittance spatial distribution or the light is distributed at an arbitrary position in the optical path between the total reflection mirror and the output side of the output mirror in the optical resonator. A laser oscillator in which a transmissive spatial light modulator capable of arbitrarily adjusting a phase change spatial distribution is arranged. 6. A laser oscillator according to claim 5, further comprising a feedback system for guiding a part of the laser light emitted from the output mirror in the optical resonator as writing light for the spatial light modulator. 7. The image pickup device according to claim 6, wherein a part of the laser beam emitted from the output mirror in the optical resonator is used as a video signal, and the video signal is processed to write in the spatial light modulator. A laser oscillator, comprising: an image processing device that outputs an image signal as light and outputs the image signal to the spatial light modulator. 8. A laser oscillator according to claim 5, further comprising an image signal generation device for generating an image signal as writing light for the spatial light modulator. 9. A reflection-type spatial light modulation including a laser medium, an excitation source, and an optical resonator, and a total reflection mirror in the optical resonator capable of arbitrarily adjusting a reflectance spatial distribution or an optical phase change spatial distribution. And a transmission type spatial light modulation that can arbitrarily adjust the transmittance spatial distribution or the optical phase change spatial distribution at an arbitrary position in the optical path between the total reflection mirror and the output side of the output mirror in the optical resonator. A laser oscillator characterized by arranging a container. 10. A laser oscillator according to claim 9, further comprising a feedback system for guiding a part of the laser light emitted from the output mirror in the optical resonator as the writing light of the spatial light modulator. 11. The imaging device according to claim 10, wherein a part of the laser light emitted from the output mirror in the optical resonator is used as a video signal, and the video signal is processed to write in the spatial light modulator. A laser oscillator, comprising: an image processing device that outputs an image signal as light and outputs the image signal to the spatial light modulator. 12. The laser oscillator according to claim 9, further comprising an image signal generation device for generating an image signal as writing light for the spatial light modulator.