JPH08334802A - Laser device and laser application device - Google Patents

Abstract

PURPOSE: To provide a laser device capable of obtaining stable laser output over a long term. CONSTITUTION: This laser device is composed of a laser crystal 21 incorporating fluoride, resonator structure including the laser crystal 21, a means for exciting the laser crystal 21, first laser beams 32 obtained by oscillating light emitted from the laser crystal 21 in a laser resonator 20, an optical components arranged in the resonator, to take a part of the first laser beams 32 out of the resonator as sample light and a means for stabilizing the output of the first laser beams 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of optoelectronics, and more particularly to a laser device used in a laser printer device, an optical modeling device, an optical recording device, a particle counter device and the like.

[0002]

2. Description of the Related Art With the progress of the advanced information age, demands for shorter wavelengths are increasing in order to satisfy the demands for recording density improvement and high speed printing in computer peripheral laser application devices such as optical disc devices and laser printer devices. There is. However, gas laser devices such as He-Cd (helium-cadmium) laser devices and Ar (argon) laser devices are the only light sources that satisfy the blue region, which is highly demanded at the commercialization level. However, there is a problem that the service life is short due to the deterioration of the gas, and it has not been put into practical use. In addition, since the laser device is large, the laser application device that incorporates the laser device as a light source needs to be at least as large as the laser device, which makes it large, and the desktop size cannot be applied to the mainstream office and residential environments. was there. Further, the efficiency of converting the input power of the laser device to the laser light is low, and most of the power consumption is heat, which requires a cooling means, which further increases the size of the laser application device. There is also a problem that the deviation of the optical system due to the vibration of the cooling means deteriorates the reliability of the laser application device.

On the other hand, a Ti: Al ₂ O ₃ (titanium-added sapphire; Ti-Sap.) Crystal, which is a laser crystal capable of oscillating in the wavelength region of 800 to 900 nm, or a laser crystal containing a fluoride. Cr: LiSrAlF ₆ crystal (hereinafter simply referred to as Li
An internal resonator type SHG (Second Harmonic Generation) method, which is one of the wavelength conversion methods using a first laser beam generated by a laser apparatus using a LiSAF crystal called a SAF crystal and a LiSAF laser) was proposed. (Former; L. S. Wu, H. Luther, P. Gunter "High-efficiency internal cavity type frequency doubling of Ti: Al ₂ O ₃ laser using KNbO ₃ crystal", Applied Physical Communication, Vol. 56, No. 22, p. 2163 ( 1990), LS Wu,
H. Looser, and P. Gunter, "High-effciency intracavi
ty frequency doubuling of Ti: Al ₂ O ₃ lasers with KNbO ₃
crystals ", Appl.Phys.Lett., Vol.56, No.22, p.2163 (199
0), and U.S. Pat. No. 5,034,949, the latter; F. Ballenbow,
P. Jorgy, F.S. Alan, "Tunable blue light source with internal resonator type frequency multiplication of Cr-doped LiSrAlF ₆ laser"
Applied Physical Communication Vol. 61, No. 20, pp. 2381 (1992), F. Balembois,
P. Georges, F. Salin, G. Roger, and A. Brun, "Tunable
blue lightsource by intracavity frequency doublin
gof a Cr-dope LiSrAlF ₆ laser ", Appl.Phys.Lett., Vol.
61, No. 20, p2381 (1992)). However, both types of pumping light sources are SHG lasers (wavelength: 5
32 nm), the latter is a Kr laser (wavelength: 647, 676)
Since the size and power consumption are large and the life is short, the gas laser device described above has not been greatly improved. Further, in both systems, the output is a pulse and not a continuous wave, so there was a practical problem.

On the other hand, it has already been disclosed that the LiSAF crystal can be excited by a red semiconductor laser having a wavelength of 670 nm (R. Skeps, JF Mayer, HB sellers, A. Rosen). Berg, R.C. Morris, M. Long, "Semiconductor Laser Excited Cr: LiSrAlF ₆ Laser", Optical Communication, Vol. 16, No. 11, 820 (1991), R. Scheps, JF Myer
s, HB Serreze, A. Rosenberg, RC Morris, and M.
Long, "Diode-pumped Cr: LiSrAlF ₆ laser", Opt.Lett., V
ol. 16, No. 11, p820 (1991)). The LiSAF laser and Ti-Sap. A laser using a LiSAF crystal which is a fluoride-containing laser crystal among the lasers can excite a semiconductor laser, and the problems of size, power consumption, and life of a conventional gas laser have been solved by the wavelength conversion method of the semiconductor laser excitation LiSAF laser. It is expected that the SHG laser, which is one, can make a great improvement.

[0005]

However, as far as we know, the output stability of a semiconductor laser pumped LiSAF laser or a wavelength conversion laser including the SHG thereof has not been reported. Generally, the factors that cause fluctuations in solid-state laser output are:
Relative vibration of the optical components that make up the laser cavity in a short time, fluctuations in the temperature distribution within the laser crystal, fluctuations in pumping light, competition between longitudinal modes and relaxation oscillations, and effective optical paths of optical components due to temperature changes There is a long fluctuation, and over a long period of time, it is considered that the excitation light is deteriorated due to the deterioration of the excitation light source, the mirror is deteriorated, and the antireflection film of the optical component is deteriorated. Also, SHG
In the case of a wavelength conversion laser including, it is considered that the phase matching wavelength varies with the temperature variation of the nonlinear optical crystal.

Among these fluctuation factors, coupling between longitudinal modes and relaxation oscillation are caused by LiSAF laser and LiSAF.
It is one of the main fluctuation factors of the wavelength conversion laser output including the SHG of the laser. In other words, the LiSAF laser has a very wide gain bandwidth of 220 nm, which is 780 to 1000 nm, so that it oscillates in a longitudinal multimode of about 10 nm without a control mechanism (Shineichiro Aoshima, Haruyasu Ito, Nei Obayashi, Hirano). Isuke "Cr: LiSAF Laser",
Optical and Quantum Device Study Group, OQD-92-13 (1992)). Therefore, mode competition occurs between the longitudinal modes, resulting in output noise. As one of the means for reducing the mode competition noise, there is a means for making the longitudinal mode single by using an optical component having a wavelength control function.

FIG. 7 is a diagram for explaining a means for measuring the relationship between the longitudinal mode bandwidth of the LiSAF laser and the power of the oscillation beam of the LiSAF laser. A birefringent filter made of quartz is used as the wavelength control element 23.
Generally, the wavelength dependence of the transmittance of the birefringent filter 23 changes depending on the thickness of the filter, and the thicker the thickness, the steeper the peak of the transmittance. In addition, the plurality of birefringent filters 23
In case of overlapping, the transmittance is the product of the respective transmittances. The thickness of the birefringent filter was 0.5, 1.0 and 1.5 mm, respectively. The resonator 20 is formed between the end face 24 of the LiSAF crystal 21 and the concave mirror 25, and the semiconductor laser 11 for excitation is formed.
The excitation light from the laser passes through the condensing optical system 12 and is condensed in the LiSAF crystal 21 from the same optical axis as the resonator 20.
The concave mirror 25 has a curvature of 15 cm, and the resonator length is slightly shorter than the radius of curvature and has a substantially hemispherical positional relationship. The first laser beam output 32 is separated by the half mirror 26, and the experimental configuration is such that the output and the wavelength are measured simultaneously. The measurement was performed by changing the combination of the birefringent filters 23. Table 1 is a table for explaining the measurement result of the relationship between the bandwidth of the longitudinal mode and the power of the first laser beam in the LiSAF laser when the combination of the birefringent filters is changed.

[0008]

[Table 1]

From Table 1, the band width is about 4 nm when the birefringent filter is not used, and the band narrowing down to 0.2 nm can be realized by combining three birefringent filters. However, the power of the first laser beam dropped to about 1/10. In order to realize the above-mentioned longitudinal single mode, it is necessary to combine more wavelength control elements, and it is expected that the power of the first laser beam will further decrease. That is, when a semiconductor laser having a limited output is used, it is considered that it is practically difficult to obtain a single longitudinal mode. Further, in the wavelength conversion laser including the SHG of the LiSAF laser, since the conversion efficiency of the nonlinear optical crystal used has wavelength dependence, the influence of the mode competition noise of the first laser beam is further expanded. .

Among the above-mentioned fluctuation factors, the elements that can be positively controlled include the input of excitation light and the temperature of the laser crystal. Further, in the case of a wavelength conversion laser including SHG, since the phase matching wavelength has temperature dependence in the nonlinear optical crystal, the temperature of the nonlinear optical crystal is added as a controllable element. A feedback control mechanism has been considered which acts on the controllable element in the direction of attenuating the output fluctuation using the first laser beam or SH wave sample light separated by a half mirror or the like. However, the extraction of the sample light results in a loss of the first laser beam or SH output, which is not a preferable configuration.

[0011]

As a result of intensive studies made by the present inventors with respect to the above-mentioned problems, the present invention was conceived by paying attention to reflected light already existing in a structure having a wavelength control element inside a resonator. did. That is, the present invention provides a laser crystal containing a fluoride, a resonator structure including the laser crystal, a means for exciting the laser crystal, and light emitted from the laser crystal oscillates in the laser resonator. Stabilizing the output of the first laser beam, an optical component arranged inside the resonator for extracting a part of the first laser beam as sample light to the outside of the resonator, and And a laser device comprising means for

FIG. 8, FIG. 9 and FIG. 10 are diagrams for explaining a method of extracting sample light used for feedback control. A birefringent filter or a prism was used as a means for controlling the wavelength of the LiSAF laser. FIG. 8 shows a case where the birefringent filter 23 is used as the wavelength control means. The light emission from the LiSAF crystal 21 excited by the semiconductor laser 11 is amplified by the resonator 20 and the first laser beam 3
2 is generated. The LiSAF crystal 21 is arranged so that the c-axis lies within the plane of the paper, and the plane of polarization is the same plane as the plane of the paper. Here, the birefringent filter 23 is arranged so that the entrance surface and the exit surface form the Brewster angle with respect to the optical axis of the resonance beam 32 in order to minimize the loss inside the resonator. Reflection of incident and outgoing light at Brewster's angle is significantly reduced, but slightly present. Here, since the internal power of the first laser beam 32 is usually several W or more, the first laser beam 32 of several μW to mW or more is reflected by the entrance surface and the exit surface of the prism 23 and is extracted as the sample light 34. I was able to.

FIG. 9 shows a LiSAF using a birefringent filter.
The case of a wavelength conversion laser of a laser is shown. The plane of polarization of the first laser beam 32 is also flush with the plane of the page. Here, the nonlinear optical crystal 22 converts a part of the first laser beam 32 into a second laser beam 33. Since the second laser beam 33 has a plane of polarization orthogonal to the first laser beam, it is reflected by the birefringence filter 23 by several to several tens% or more, and is partially reflected and separated similarly to the first laser beam in FIG. It was to so. FIG. 10 shows a case where the prism 27 is used as the wavelength control means. Similarly, the plane of polarization is the same as the plane of paper. Here, similarly, the prism 27 is arranged so that the incident surface and the outgoing surface have a Brewster angle with respect to the optical axis of the resonance beam. Therefore, similarly, the prism 27
Of the first laser beam 32 on the entrance and exit surfaces of
Is the reflection Brewster angle. At this time, the prism 27 is arranged inside the resonator at the Brewster angle with respect to the optical axis.
In, the resonance beam 32 is partially reflected and separated.

In the present invention, as described above, conventional LiSA is used.
In the wavelength conversion laser including the SHG using the F laser or the LiSAF laser, the unavoidable reflected light associated with the wavelength control is positively used for the feedback control, whereby the laser output can be obtained without a new loss. Further, as one of the laser output stabilizing means of the present invention, among the above-mentioned controllable factors, a means for controlling the power of pumping light is proposed. That is, in the semiconductor laser which becomes the excitation light, the phenomenon that the semiconductor laser power increases when the drive current increases and the power of the first or second laser beam increases accordingly is used.
As shown in FIGS. 8, 9, and 10, the first or second laser beam partially reflected and separated by the wavelength control means reaches the detector as sample light. The reference value of the sample light is set as a reference voltage, and the drive current of the semiconductor laser is adjusted so that the output voltage from the detector becomes equal to this reference voltage.

As another means of the laser output stabilizing means of the present invention, among the above-mentioned controllable factors, a means for controlling the temperature of the laser crystal has been proposed. That is, the fact that the power of the first or second laser beam in the LiSAF laser has the property of depending on the temperature of the laser crystal is utilized. The temperature of the laser crystal 21 is adjusted so that the reference voltage of the sample light 34 and the output voltage from the detector become equal. Another means of stabilizing the laser output of the present invention is to control the temperature of the nonlinear optical crystal among the above-mentioned controllable factors in the wavelength conversion laser of the LiSAF laser. Utilizing the property that the SHG output depends on the temperature of the nonlinear optical crystal, the temperature of the nonlinear optical crystal is controlled to stabilize the laser output. The temperature of the nonlinear optical crystal is adjusted so that the reference voltage of the sample light and the output voltage of the detector become equal. According to the present invention, a stable feedback control system is realized without generating a new loss such as taking out a part of output using a half mirror or the like.

The laser crystal is preferably a LiSAF crystal. Further, it is preferable that at least one of the plurality of mirrors forming the resonator is formed on one end surface of the laser crystal. Further, it is preferable that the optical component controls the wavelength of the first laser beam. Further, it is preferable that the optical component has a birefringence effect. Further, it is preferable that the means for exciting the laser crystal is a semiconductor laser. Further, it is preferable to have a non-linear optical element for wavelength-converting the first laser beam into a second laser beam having a different wavelength, and means for stabilizing the output of the second beam. Further, it has been proposed to use the laser device in a laser printer device, an optical modeling device, an optical recording device, a particle counter device and the like.

[0017]

【Example】

(Embodiment 1) FIG. 1 is a diagram for explaining an embodiment of the present invention. The excitation beam 31 emitted from the semiconductor laser 11 is condensed by the condensing optical system 12, and the laser crystal 21
Excite. The semiconductor laser 11 is an SDL (Spectra Diod
e Lab.) AlGaInP based semiconductor laser, output 50
It is 0 mW and the oscillation wavelength is 670 nm. The condensing optical system 12 uses a semiconductor laser collimator (f = 8 mm), an anamorphic prism pair (magnification: 6 times), and a single lens (f = 30 mm). The focal length and the like of the condensing optical system are arbitrary as long as the efficiency is not significantly reduced. An optical fiber or a cylindrical lens may be used as the beam shaping means. The excited laser crystal 21 oscillates a first laser beam 32 in the solid-state laser resonator 20 including an entrance-side resonator mirror 24 and an output mirror 25 formed on the laser crystal end face. A laser crystal 21 and a wavelength control element 23 are arranged in the resonator 20.
The wavelength of the first laser beam 32 that oscillates in the resonator is controlled by the wavelength control element 23. At this time, the resonator structure 20 is a plano-concave resonator, the radius of curvature of the output mirror 25 is 150 mm, and the effective optical path length is slightly shorter than the radius of curvature. Further, the resonator structure 20, the radius of curvature, and the effective optical path length are arbitrary as long as the efficiency is not significantly reduced.

The laser crystal 21 has a Cr addition amount of 1.5 mo.
A 1% LiSAF crystal (φ3 × 5 mm) was used. The front end face 24 of the crystal has a non-reflecting (hereinafter simply referred to as AR; Anti-Reflection) coating with a reflectance of 2% or less for the excitation wavelength, and a total reflection with a reflectance of 99% or more for the first laser beam wavelength (hereinafter Only HR; High-Reflection) coating was applied. Here, the reflectance of the HR coating is 95
% Or more may be used, and it is not particularly required to be 99% or more. An AR coating having a reflectance of 2% or less for the first laser beam wavelength was applied to the rear end surface. The output mirror 25 has H of 99% or more for the first laser beam.
R coating was applied. A birefringent filter made of a quartz plate was used as the wavelength control element 23, and the wavelength control element 23 was arranged so as to have a Brewster angle with respect to the first laser beam 32. The wavelength of the first laser beam 32 can be controlled by rotating the birefringent filter around the optical axis. The wavelength control range was about 860 ± 50 nm, and the wavelength selection width was about 0.5 nm. Here, the wavelength control width can be changed by superimposing quartz plates having different thicknesses that are integral multiples, and is arbitrary within a range in which the first laser beam output is not significantly reduced. The wavelength control element 23 may use a prism or an etalon.

Further, in the present invention, it has been shown that feedback control is possible by using the first laser beam separated from the resonator by the wavelength control element 23 as the sample light 34. Based on this, the first laser beam partially reflected and separated by the wavelength control element 23 reaches the detector 41 as sample light 34. The reference value of the sample light 34 is set as a reference voltage, and the drive current of the semiconductor laser 11 is adjusted so that the output voltage of the detector 41 becomes equal to this reference voltage.
With such a structure, a stable laser output could be obtained. Further, the wavelength allowable width of absorption of the LiSAF crystal 21 is as wide as about 100 nm, but the wavelength of the semiconductor laser for excitation was not controlled by using a temperature control element or the like, but it may be controlled to match the maximum absorption wavelength.

(Embodiment 2) FIG. 2 is a diagram for explaining one embodiment of the present invention. The semiconductor laser 11, the condensing optical system 12, the resonator structure, the wavelength control element 23, and the like are the same as in the first embodiment
Same as. It was shown that feedback control can be performed by using the first laser beam separated from the resonator 20 by the wavelength control element 23 as the sample light 34 as in the first embodiment. Based on this, the first laser beam partially reflected and separated by the wavelength control means reaches the detector 41 as the sample light 34. Sample light 3
4, a reference value is set as a reference voltage, and L is set so that the output voltage of the detector 41 becomes equal to this reference voltage.
The temperature of the iSAF crystal 21 is adjusted. With such a structure, a stable laser output could be obtained.

(Embodiment 3) FIG. 3 is a diagram for explaining one embodiment of the present invention. The excitation optical system including the semiconductor laser 11 was the same as that used in Example 1. The excited laser crystal 21 is a first laser beam 32 which is a solid-state laser oscillation wave in the solid-state laser resonator 20 including an incident-side resonator mirror 24 and an output mirror 25 formed on the laser crystal end face.
Occurs. A laser crystal 2 is provided in the solid-state laser resonator 20.
1, a non-linear optical crystal 22 and a wavelength control element 23 are arranged. LiB ₃ O ₅ crystal (lithium borate; hereinafter referred to as LBO crystal) is used as the nonlinear optical crystal 22 and has a size of 3 ×.
AR coating of 3% or less and 2% or less for the first laser beam and the SH wave wavelength was applied. The LBO crystal 22 was set at 25 ± 0.1 ° C. by using a temperature control element. The output mirror 25 has 99 for the first laser beam.
% Or more of HR coating is A for SH wave 33
R coating is applied and the opening is φ10 mm as in Example 1.
And The other optical components used were the same as in Example 1. First laser beam 32 oscillating in resonator 20
Is controlled by the wavelength control element 23 to a wavelength at which the wavelength conversion efficiency of the nonlinear optical crystal 22 is maximized, and a part of the first laser beam 32 is generated by the nonlinear optical crystal 22 as a second harmonic (SH wave) 33. Wavelength converted to about 20% S
After the H wave is separated from the optical axis by the wavelength control element 23,
It is emitted from the output mirror 25. Here, the wavelength control element 2
Approximately 20% of the SH waves separated by the sample light 34
And was used as feedback control. The reference value of the sample light 34 is set as a reference voltage, and the temperature of the nonlinear optical crystal 22 is adjusted so that the output voltage of the detector 41 becomes equal to this reference voltage. Instead of the temperature of the nonlinear optical crystal 22, the drive current of the semiconductor laser 11 or the temperature of the LiSAF crystal 21 may be adjusted.

The wavelength control range was about 860 ± 70 nm, and the wavelength selection width was 0.5 nm. Here, the wavelength control range is L
It can be adjusted in the vicinity of the wavelength where the conversion efficiency of the BO crystal 22 is maximized, and the wavelength selection width is arbitrary as long as the SH output 33 does not significantly decrease. Also, instead of the LBO crystal 22, KNbO ₃ (potassium niobate), KL-N (potassium lithium niobate), β-BaB ₂ O ₄ (barium borate), LiIO ₃ (lithium iodide), or the like is used. May be. At this time, it is necessary to control the wavelength to a wavelength selection width suitable for the wavelength dependence of the SHG conversion efficiency of the nonlinear optical crystal 22 used.

(Embodiment 4) FIG. 4 is a diagram for explaining one embodiment of the present invention. The blue laser output 33 emitted from the blue laser light source 100 described in FIG. 3 includes an acousto-optic (AO; Acousto-Optical) modulator 51, a beam expander 52, a rotating polygon mirror 53, and an fθ lens 54.
And is focused on the photosensitive drum 55. AO modulator 5
Reference numeral 1 modulates the SFG output 43 in accordance with the image information, and the rotary polygon mirror 53 scans in the horizontal (in-plane) direction. With this combination, the two-dimensional information is recorded on the photosensitive drum 55 as a partial potential difference. The photosensitive drum 55 attaches toner according to the potential difference and rotates to reproduce information on a recording sheet.
At this time, the photoconductor coated on the photoconductor drum 55 is selenium (Se), the output wavelength of the blue laser light source 100 is 420 nm, which is relatively high in sensitivity of the photoconductor, and the output is 15 mW.
And

(Embodiment 5) FIG. 5 is a diagram for explaining one embodiment of the present invention. As the light source, the blue laser light source 100 described in FIG. 3 was used. The container is filled with the blue cured resin 61, and the laser light is two-dimensionally scanned on the liquid surface. At this time, the blue curable resin 61 cures only the liquid surface portion 61-a where the light is absorbed. When the formation of one fault is completed, the elevator 62 descends, and the shaping of the next fault is continuously performed. By this work, the three-dimensional model 63 having a desired shape can be created. At this time, the blue laser light source has a wavelength of 430 nm and an output of 30 mW
And

(Embodiment 6) FIG. 6 is a view for explaining an embodiment of the present invention and shows an optical disk device.
The blue laser light source 100 described in FIG. 2 was used as the light source. The optical disk device adopts a magneto-optical recording method. The blue laser output 33 emitted from the blue laser light source 100 is expanded by the beam expander 52 and becomes parallel light.
The light partially bounced by the beam splitter 72 is captured by the front monitor 73. The beam that has passed through the beam splitter 72 is condensed on the medium 75 by the condensing optical system 74, and the reflected light is partially reflected by the beam splitter 72 and then separated into two beams, which are respectively taken into two detectors 76. . The front monitor 73 monitors the blue laser output 33 and controls the blue laser output 33. Further, the two detectors 76 after the beam splitter 72 perform autofocus and signal detection, respectively. A constant magnetic field was applied to the medium 75, and recording was performed by modulating the blue laser output 33 by the AO modulator 51 to raise the focus temperature to the Curie temperature of the medium 75 and reversing the magnetization.
When the output is ON, the magnetic field of the medium is reversed, and when the output is OFF, the magnetic field is not reversed and signal recording is possible. The recording frequency was 10 MHz. Further, at the time of signal reproduction, the same blue laser light source 100 as that at the time of recording was used to obtain a good reproduction signal.

[0026]

INDUSTRIAL APPLICABILITY The present invention has proposed a means for stabilizing the laser output of the LiSAF laser and the wavelength conversion laser including the SHG using the LiSAF laser without causing new loss. According to the present invention, the reliability of the laser device is improved. Also, the number of parts for separating the beam has been reduced.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining an example of the present invention.

FIG. 3 is a diagram for explaining an example of the present invention.

FIG. 4 is a diagram for explaining an example of the present invention.

FIG. 5 is a diagram for explaining one embodiment of the present invention.

FIG. 6 is a diagram for explaining an example of the present invention.

FIG. 7 is a diagram for explaining a means for measuring the relationship between the bandwidth of the longitudinal mode of the LiSAF laser and the power of the oscillation beam of the LiSAF laser.

FIG. 8 is a diagram for explaining a method of extracting sample light used for feedback control.

FIG. 9 is a diagram for explaining a method of extracting sample light used for feedback control.

FIG. 10 is a diagram for explaining a method of extracting sample light used for feedback control.

[Explanation of symbols]

100 SHG-containing wavelength conversion light source, 11 semiconductor laser, 12 condensing optical system 20 resonator, 21 laser crystal, 22 nonlinear optical crystal, 23 wavelength control element, 24
(Injection side) resonator mirror, 25 output mirror, 26
Half mirror, 27 prisms, 31 excitation beam, 3
2 first laser beam, 33 second laser beam (blue laser, SH wave), 34 sample light, 41
Detector, 51 AOM, 52 beam expander, 53 rotating polygon mirror, 54 fθ lens, 55 photosensitive drum, 61 blue effect resin, 62 elevator, 63
3D model, 72 beam splitter, 73 front monitor, 74 condensing optical system, 75 medium, 76 detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masazumi Sato 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Inside Hitachi Metals, Ltd.

Claims (24)

[Claims] 1. A laser crystal containing fluoride, a resonator structure containing the laser crystal, means for exciting the laser crystal, and light emitted from the laser crystal oscillates in the laser resonator. A first laser beam composed of, an optical component arranged inside the resonator for extracting a part of the first laser beam as sample light to the outside of the resonator, and an output of the first laser beam. A laser device comprising a stabilizing means. 2. The laser device according to claim 1, wherein the laser crystal is Cr: LiSrAlF ₆ (chromium-added lithium strontium aluminum fluoride). 3. The laser device according to claim 1, wherein at least one of a plurality of mirrors forming the resonator is formed on one end surface of the laser crystal. 4. The laser device according to claim 1, wherein the optical component controls the wavelength of the first laser beam. 5. The laser device according to claim 1, wherein the optical component has a birefringence effect. 6. The laser device according to claim 1, wherein the means for exciting the laser crystal is a semiconductor laser. 7. The method according to claim 1, wherein the means for stabilizing the first laser beam is a means for changing the pumping input according to the fluctuation of the output of the sample light.
The laser device according to any one of 1. 8. The method according to claim 1, wherein the means for stabilizing the first laser beam is a means for changing the temperature of the laser crystal according to the fluctuation of the output of the sample light. The laser device according to claim 1. 9. A laser crystal made of Cr: LiSrAlF ₆ , a resonator structure including the laser crystal, a semiconductor laser for exciting the laser crystal, and light emitted from the laser crystal oscillates in the laser resonator. The wavelength λ
₁ is a 780 ≦ λ ₁ ≦ 1000 nm first laser beam, a birefringent filter disposed inside the resonator for extracting a part of the first laser beam as sample light to the outside of the resonator, and the first laser beam. As a means for stabilizing the output of the laser beam, and a means for changing the excitation input to the laser crystal according to the variation of the output of the sample light. 10. A laser crystal containing fluoride, a resonator structure containing the laser crystal, means for exciting the laser crystal, and light emitted from the laser crystal oscillates in the laser resonator. A first laser beam, a non-linear optical element for wavelength-converting the first laser beam into a second laser beam having a different wavelength, and a part of the second laser beam as sample light outside the resonator. A laser device comprising: an optical component disposed inside the resonator to be taken out; and means for stabilizing the output of the second beam. 11. The laser crystal is Cr: LiSrAlF ₆ (chromium-added lithium strontium aluminum fluoride).
11. The laser device according to claim 10, wherein 12. The laser device according to claim 10, wherein at least one of the plurality of mirrors forming the resonator is formed on one end surface of the laser crystal. 13. The laser device according to claim 10, wherein the optical component controls the wavelength of the first laser beam. 14. The laser device according to claim 10, wherein the optical component has a birefringence effect. 15. The oscillation wavelength width Δλ ₁ of the first laser beam is 0.01 ≦ Δλ ₁ ≦ 1n by the wavelength control element.
10. The method according to claim 10, wherein the control is performed at m.
4. The laser device according to any one of 4. 16. The laser device according to claim 10, wherein the means for exciting the laser crystal is a semiconductor laser. 17. The method according to claim 10, wherein the means for stabilizing the second laser beam is a means for changing the pumping input to the laser crystal according to the fluctuation of the output of the sample light. 16. The laser device according to any one of 16. 18. The laser according to claim 10, wherein the means for stabilizing the second laser beam is a means for changing the temperature of the non-linear optical element according to a change in the output of the sample light. apparatus. 19. A laser crystal made of Cr: LiSrAlF ₆ ;
A resonator structure including the laser crystal, a semiconductor laser for exciting the laser crystal, and a wavelength λ _{1 formed} by oscillation of light emitted from the laser crystal in the laser resonator is 780 ≦ λ ₁ ≦ 1000 nm. The first laser beam and the first laser beam have a wavelength λ ₂ of 390 ≦ λ ₂ ≦
A non-linear optical element for wavelength conversion into a second laser beam of 500 nm, and a birefringent filter arranged inside the resonator capable of extracting a part of the second laser beam as sample light to the outside of the resonator. A laser device comprising means for stabilizing the output of the second beam, and means for changing the pumping input according to the variation of the output of the sample light. 20. A laser application apparatus using the laser apparatus according to any one of claims 1 to 19. 21. The laser application apparatus according to claim 20, wherein the laser application apparatus is a laser printer apparatus. 22. The laser application apparatus according to claim 20, wherein the laser application apparatus is a stereolithography apparatus. 23. The laser application apparatus according to claim 20, wherein the laser application apparatus is an optical recording apparatus. 24. The laser application apparatus according to claim 20, wherein the laser application apparatus is a particle counter apparatus.