JP3067313B2 - Solid-state laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser device in which a solid-state laser medium is excited by a semiconductor laser to cause laser oscillation.

[0002]

2. Description of the Related Art An example of a conventional solid-state laser device is shown in FIG. In FIG. 7, a conventional solid-state laser device 100 is shown.
Is a semiconductor laser 116 disposed on the optical axis, a condenser lens 152 for condensing the emitted light 120 emitted from the semiconductor laser 116, and a solid-state laser excited by the emitted light 120 of the semiconductor laser 116. Rod 150
And an output mirror 114. The solid-state laser rod 150 is connected to the solid-state laser medium 1.
And a coating layer 111 provided on the end face of the medium 110 on the semiconductor laser 116 side, transmitting the emitted light 120 of the semiconductor laser 116 and highly reflecting the fundamental wave 118 of the solid-state laser. That is, the solid-state laser rod 15
0 and the output mirror 114 constitute an optical resonator.

The operation of such a conventional solid-state laser device will be briefly described. First, the semiconductor laser 11
6 excites the solid-state laser rod 150 and resonates, so that the fundamental wave 1 of the solid-state laser
18 is generated. A part of the generated fundamental wave 118 passes through the output mirror 114 and is output to the outside. In this conventional example, for example, Nd:
When YAG is used, laser light having a wavelength of 1064 nm can be obtained.

[0004]

However, the conventional solid-state laser device requires a space for incorporating the condenser lens 152, which is disadvantageous for downsizing the device.
Further, the adjustment of the optical axis of the condenser lens 152 and the adjustment of the position such as the focal length are complicated, and this is one of the causes that productivity is not improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a compact, easy-to-operate and high-efficiency solid-state laser device with a simple machining process. It is in.

[0006]

In order to achieve such an object, the present invention provides a laser medium excited by light,
In the solid-state laser device having the optical resonator including the laser medium, the laser medium includes two end surfaces arranged perpendicular to an optical axis, and at least one of the end surfaces is formed of a non-transmissive resin. A nonlinear optical element having a planar structure and a non-planar structure made of a light-transmitting resin on an end face is incorporated in the optical resonator.

[0007]

According to the solid-state laser device of the present invention having the above-described structure, the emitted light of the semiconductor laser is condensed by the translucent resin and is efficiently absorbed by the solid-state laser rod.

[0008] At this time, since the nonlinear optical element having the non-planar structure portion made of the translucent resin on the end face is incorporated in the optical resonator, a harmonic laser beam can be obtained with a simple configuration.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to FIGS. FIG. 1 shows a solid-state laser device as a first embodiment of the present invention. In FIG. 1, a solid-state laser device 1 according to the present invention converges a semiconductor laser 16 arranged on an optical axis, an emission light 20 emitted from the semiconductor laser 16, and is excited by the emission light 20. Solid laser rod 13 and solid laser rod 13
Output mirror 14 located on the optical axis slightly away from
And

The solid-state laser rod body 13 includes a laser rod 10 serving as a substantially cylindrical laser medium, a coating layer 11 formed on one end face of the laser rod 10 (semiconductor laser 16 side), 1
Curved surface 15a as a non-planar structure formed on
And a lens body 15 having:

The laser rod 10 is made of, for example, Nd: Y
It is an AG crystal and has two end faces 10a and 10b arranged perpendicularly to the optical axis as shown in the figure. As the coating layer 11, it is highly reflective to light having a wavelength of 1064 nm, while A material having high transmission with respect to light having a wavelength of 808 nm, for example, a refractive index of 2.35 and a thickness of 86 mm
ZnS, MgF ₂ having a refractive index of 1.38 and a thickness of 146 mm
Is used. Lens body 15
Is formed by irradiating a light-transmitting resin, particularly an ultraviolet-curable resin, with ultraviolet rays to cure the resin, and has a so-called plano-convex lens shape as shown in the figure.

The output mirror 14 usually has a so-called plano-concave lens shape, which transmits a part of the light of 1064 nm and reflects light of other wavelengths. The output mirror 14 and the coating 11 form an optical resonator.

Next, the operation of the laser device 1 having such a configuration will be described. First, the excitation light 20 having a wavelength of 808 nm emitted from the semiconductor laser 16 is condensed by the lens body 15 having a lens shape, and is absorbed by the Nd: YAG laser rod 10. Here, the Nd: YAG laser rod 10 absorbs the excitation light 20 and generates a fundamental wave 18 having a wavelength of 1064 nm by stimulated emission and resonance operation. A part of the generated fundamental wave 18 is transmitted to the outside through the output mirror 14.

Next, a method for manufacturing the solid-state laser rod 13 will be described with reference to FIG. First, a mold 40 having a desired lens shape is made of a material that transmits ultraviolet light, for example, SiO ₂ . N with coating layer 11
d: The YAG laser rod 10 is fitted into the prepared mold 40. After pouring an ultraviolet curable resin as a material of the lens body 15 into the mold 40, the resin is cured by irradiating ultraviolet rays. Thereafter, the mold 40 is removed, and the solid-state laser rod body 13 having a lens shape is completed.

FIG. 2 shows a second embodiment of the solid-state laser device according to the present invention. The second embodiment differs from the first embodiment in that the output mirror is omitted, and only the point that an object corresponding to the output mirror is incorporated in the solid-state laser rod body 24 is different. That is, a lens body 17 having a curved surface 17a as a non-planar structure is formed on the other end of the laser rod 10 (the side opposite to the semiconductor laser 16), and the coating layer 2 is formed on the curved surface of the lens body 17.
2 are formed. The lens body 17 has a plano-convex lens shape as shown in the figure, and is formed by irradiating an ultraviolet curable resin with ultraviolet rays and curing the same as the lens body 15. The coating layer 22 is coated with a coating material that transmits only a part of the wavelength of 1064 nm and reflects light of other wavelengths and has the same function as the output mirror 14. Specifically, Zn with a refractive index of 2.35
A multilayer film or the like configured to satisfy a desired condition with S and MgF ₂ having a refractive index of 1.38 is exemplified.

With such a configuration, the process of generating the Nd: YAG laser fundamental wave is the same as that of the first embodiment.

Next, an example in which the above-described solid-state laser device is applied to second harmonic generation will be described as a third embodiment with reference to FIG. The solid-state laser device 3 shown in FIG.
As the nonlinear optical element 26 for generating harmonics, for example, KT
iOPO ₄ (hereinafter abbreviated as KTP) is provided in the optical resonator. That is, the non-linear optical element 26 is interposed between the solid-state laser rod 13 and the output mirror 27 as shown. In this case, the output mirror 27
High reflection is set for 4 nm light, and high transmission for 532 nm light. In such a solid-state laser device, a part of the fundamental wave 18 resonating in the optical resonator is
It is converted into a second harmonic 28 in the KTP of the nonlinear optical element 26. Since the wavelength of the second harmonic 28 is 532 nm, it is transmitted through the output mirror 27 and output to the outside.

As shown in FIG. 4, the solid-state laser device for generating the second harmonic has a KT of the nonlinear optical element 26.
It is also possible to form an optical resonator by forming a lens body 17 of an ultraviolet curable resin on the P end face and having the same function as the output mirror 27 (fourth embodiment). At this time, after the lens body 17 is formed on the end face of the KTP of the nonlinear optical element 26 with an ultraviolet curing resin, the coating layer 22 is applied on the lens body 17. Like the output mirror 27, the coating layer 22 is set to have a high reflection for light having a wavelength of 1064 nm and a high transmission for light having a wavelength of 532 nm.

Next, an example in which this solid-state laser device is applied to sum frequency generation is shown in FIG. 5 as a fifth embodiment. In this figure, the solid-state laser device 5 includes a semiconductor laser 16 arranged on the optical axis, for example, KTP as a sum frequency generation nonlinear optical crystal 30, and a solid-state laser rod 32. The non-linear optical crystal 30 for sum frequency is provided on one end face (on the side of the semiconductor laser 16) with a coating layer 11 having high reflection for light with a wavelength of 1064 nm and high transmission for light with a wavelength of 808 nm. . Further, on the coating layer 11, a lens body 15 having a curved surface is formed by an ultraviolet curable resin. Further, a lens body 17 having a curved surface made of an ultraviolet curable resin is formed on the output end face of the solid-state laser rod body 32, and a coating layer 34 is further formed on the lens body 17 to form an optical resonator. Make up the vessel. The KTP as the nonlinear optical crystal 30 for sum frequency generation differs from the KTP as the nonlinear element 26 for second harmonic generation shown in FIGS. 3 and 4 in the direction of the crystal axis with respect to the optical axis. Are different from each other. KTP as the nonlinear optical crystal 30 for sum frequency generation used here
Is the wavelength of the emitted light of the semiconductor laser at 808 nm, and Nd:
The phase matching condition is satisfied at the wavelength of the YAG laser fundamental wave of 1064 nm, and a blue laser beam having a wavelength of 459 nm is generated. The coating layer 11 is made of a material that has high transmission with respect to light having a wavelength of 808 nm and high reflection with respect to light having a wavelength of 1064 nm. A material that is highly transmissive to the light is used. Therefore, the wavelength of 459 nm generated by the KTP as the nonlinear optical crystal 30
Is transmitted through the coating layer 34 and output to the outside.

[0020] Incidentally, in the solid-state laser medium in the present embodiment Nd: While using YAG, Nd: such YVO _4, but may be another solid-state laser medium. Further, although KTP is used for the nonlinear optical element, other nonlinear optical materials such as an organic nonlinear optical element may be used. In addition, various changes can be made without departing from the gist of the present invention. For example, in this embodiment, the solid laser rod and the non-linear optical element are formed with a non-planar structure using an ultraviolet curable resin. .

[0021]

As is apparent from the above description,
Since the solid-state laser device of the present invention does not require a condenser lens for excitation light, it can be downsized, and the adjustment of the optical axis and the alignment of the condenser lens can be simplified.

Further, since a nonlinear optical element having a non-planar structure portion made of a translucent resin on the end face is incorporated in the optical resonator, a harmonic laser beam can be obtained with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a solid-state laser device as a first embodiment.

FIG. 2 is a configuration diagram of a solid-state laser device as a second embodiment.

FIG. 3 is a configuration diagram of a second harmonic generation solid-state laser device as a third embodiment.

FIG. 4 is a configuration diagram of a second harmonic generation solid-state laser device as a fourth embodiment.

FIG. 5 is a configuration diagram of a solid-state laser device for sum frequency generation as a fifth embodiment.

FIG. 6 is an explanatory diagram of manufacturing a lens shape using an ultraviolet curable resin.

FIG. 7 is a configuration diagram of a conventional solid-state laser device.

[Description of Signs] 10 ... Laser rod as laser medium 16 ... Semiconductor laser 26 ... KTP for second harmonic generation 30 ... KTP for sum frequency generation

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-137292 (JP, A) JP-A-2-277006 (JP, A) JP-A-2-219032 (JP, A) JP-A 63-137 266405 (JP, A) JP-A-64-62621 (JP, A) JP-A-2-28980 (JP, A) JP-A-2-216879 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01S 3/06 H01S 3/0941 H01S 3/108-3/109

Claims (2)

(57) [Claims] 1. A solid-state laser device comprising: a laser medium excited by light; and an optical resonator including the laser medium, wherein the laser medium includes two end faces arranged perpendicular to an optical axis; A nonlinear optical element having a non-planar structure portion made of a translucent resin on at least one of the end faces and a non-planar structure portion made of a translucent resin on the end face is incorporated in the optical resonator. A solid-state laser device characterized by the above-mentioned. 2. The solid-state laser device according to claim 1, wherein said non-planar structure portion is a curved surface as a lens.