JPH03293789A - Ld pumped solid state laser oscillator - Google Patents

Abstract

PURPOSE:To eliminate adjusting work of optical axis and to prevent lowering of laser output by providing a total reflection mirror and a partially transparent mirror of dielectric multilayer film, respectively, on the opposite faces of a laser medium and bonding an ultrasonic oscillator directly to the other face of the laser medium. CONSTITUTION:Opposite faces of a laser medium 10 are polished to satisfy the conditions of an resonator and deposited with dielectric multilayer films so that a mirror 11 passing several % to several tens % of laser beam is formed on one end face whereas a total reflection mirror 12 is formed on the other end face. Exciting beam outputted from a semiconductor laser diode 13 is absorbed in the laser medium 10 and excites the medium atoms. Furthermore, an ultrasonic oscillator 14 is bonded directly to the top face of the laser medium 10. Upon application of an electric field from a high frequency power supply 15, the ultrasonic oscillator 14 produces ultrasonic wave and inducing a compression wave in the laser medium 10. Consequently, adjusting work of optical axis is eliminated, shift of optical axis due to vibration or temperature is suppressed and lowering of laser output is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an LD-pumped solid-state laser oscillator, and particularly to an LD-pumped solid-state laser oscillator that performs optical pumping with a semiconductor laser diode (hereinafter referred to as LD) to obtain Q-switched oscillation light. The present invention relates to an LD pumped solid state laser oscillator suitable for use in a switch oscillator.

[Conventional technology]

A conventional LD-pumped solid-state laser oscillator for obtaining Q-switched oscillation light is composed of a solid-state laser medium 11, a partially transmitting mirror 2, and an 0-switch element 3, as shown in FIG.

The optical resonator of the laser oscillator is composed of a total reflection mirror 4 and a partial transmission mirror 2 deposited on the end face of a solid-state laser medium 1.

Further, the excitation light emitted from the LD 5 passes through a total reflection mirror 4 and is focused within the solid-state laser medium 1.

Here, all the mirrors 4 have a wavelength of 99.
It has a total reflection characteristic of 9% or more, and has a dichroic characteristic that has a reflection characteristic of only a few percent with respect to the excitation light wavelength. The excited solid-state laser medium l is amplified by the optical resonator and output from the partially transmitting mirror 2.

The Q-switch element 3 is an ultrasonic modulator in which an ultrasonic vibrator is bonded to an optical medium such as lead glass or quartz. When the elastic waves generated by applying a high-frequency electric field to the vibrator propagate through the optical medium, the dense and dense regions generated in the medium diffract the passing light and modulate the light intensity of the transmitted light. By inserting it inside the resonator of a Rade oscillator, it produces an optical shutter effect. Furthermore, when ultrasonic waves are being generated, the laser oscillation stops due to the loss of diffracted light, and a Q-switch with high light intensity is obtained at the moment when the ultrasonic waves stop being generated.

[Problem to be solved by the invention]

However, in a conventional LD-pumped solid-state laser oscillator, the solid-state laser medium 11 partially transmitting mirror 2 and Q-switch element 3 are separated, so in order to obtain laser light, each part must be used to generate the same light. It was necessary to perform adjustment work to adjust it on the axis. Furthermore, since they are individually separated, misalignment of the holding portions, thermal expansion, and the like may cause a decrease in laser output.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, an object of the present invention is to provide an LD-pumped solid-state laser oscillator that eliminates the need for optical axis adjustment work and prevents a decrease in laser output.

[Means to solve the problem]

In order to achieve this object, the present invention provides an LD using a semiconductor laser diode as an excitation light source for a solid-state laser medium.
In a pumped solid-state laser oscillator, the two surfaces of the laser medium are a total reflection mirror and a partial transmission mirror made of a dielectric multilayer film, and a vibrator that generates ultrasonic waves is directly bonded to the other surface of the laser medium. It is structured as follows.

[Effect]

In this way, in the present invention, since a single laser medium includes a laser resonator shift and a Q switch function, there is no need for optical axis adjustment, and the Q of a solid-state laser can be adjusted by simply applying excitation light from an LD. Switch pulse light is obtained. Furthermore, since the individual parts are concentrated in one solid body, optical axis deviation due to vibration or temperature can be reduced, and a decrease in laser output can be prevented.

〔Example〕

Next, the present invention will be explained with reference to the drawings. .

FIG. 1 is a schematic configuration diagram showing an embodiment of an LD pumped solid-state laser oscillator according to the present invention, and FIG. 2(a).

(b) is a cross-sectional view and a vertical cross-sectional view of a laser medium.

Both end faces of the laser medium 100 are polished to meet the conditions for becoming a resonator, such as parallel planes or concave and flat surfaces, and a dielectric multilayer film is deposited on both end faces, and one end face is It is a partially transmitting mirror 11 that transmits light with a laser wavelength of several 10%, and the other end surface is 9.
The total reflection mirror 12 reflects 9.9% or more.

Furthermore, the excitation light output from the LD 13 is absorbed within the laser medium 10 and excites the atoms of the medium. Further, an ultrasonic vibrator 14 is directly adhesively fixed to the upper surface of the laser medium 10, and this ultrasonic vibrator 14 is connected to a high frequency power source 15.
The applied electric field generates ultrasonic waves and generates compression waves in the laser medium 10.

Now, as shown in FIG. 2(A), the optical axis 16 of the laser beam and the wavefront 17 of the ultrasonic wave are tilted at the Black angle in order to maximize the diffraction efficiency.

For this reason, the upper surface 10a of the laser medium 10 is polished in advance with an angle θ expressed by the following formula with respect to the optical axis 16,
The ultrasonic vibrator 14 is bonded to the upper surface 10a of this polished laser medium 1D. Note that here, λ○ indicates the wavelength of the laser beam, and λS indicates the wavelength of the ultrasonic wave in the laser medium 10.

For example, when a YAG crystal is used as the laser medium 10 and the frequency of the high-frequency power applied to the ultrasonic transducer 14 is 80 MH2, the upper surface 10a of the laser medium 10
is inclined by about 057 with respect to the optical axis 16. In addition, the high frequency power required for conventional Q-switch elements can reduce the diffraction loss of the Q-switch element inserted into the laser resonator by 1.
If the optical medium of the Q-switch element is estimated to be 0%, it will be approximately 0.2W when the optical medium is quartz, and approximately 0.2W when the optical medium of the Q-switch element is lead glass. It is IW. When a YAG crystal is used as the laser medium 10 as in this embodiment, a high frequency power of approximately 4 W is required to obtain a diffraction efficiency equivalent to that of a conventional Q-switch element. Further, even when a glass material doped with Nd (neodymium) is used as the laser medium 1o, Q-switch oscillation can be obtained by the method of this embodiment.

Note that the reason why the lower surface 10b of the laser medium 10 is formed obliquely as shown in FIG. 2(B) is to prevent the ultrasonic waves from being specularly reflected and causing loss to the laser beam.

〔Effect of the invention〕

As explained above, according to the LD-pumped solid-state laser oscillator according to the present invention, the two surfaces of the laser medium are a total reflection mirror and a partial transmission mirror formed by a dielectric multilayer film, and the other surface of the laser medium A vibrator that generates ultrasonic waves is directly bonded to the oscillator, and a single laser medium includes a laser resonator and a Q-switch function, eliminating the need for optical axis adjustment. It has the effect that a Q-switched pulsed light of a solid-state laser can be obtained by simply giving . Furthermore, since the individual parts are concentrated in one solid laser medium, optical axis deviation due to vibration and temperature can be reduced, and a decrease in laser output can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an LD pumped solid-state laser oscillator according to the present invention, FIG. 2(A) is a cross-sectional view of the laser medium, FIG. FIG. 3 is a schematic configuration diagram of a conventional example. 0... Laser medium, 1... Partial transmission mirror 2... Total reflection mirror 4... Ultrasonic transducer. 10a...Top surface, 3...LD.

Claims (1)

[Claims] In an LD-pumped solid-state laser oscillator using a semiconductor laser diode as a pumping light source for a solid-state laser medium, two surfaces of the laser medium are composed of a total reflection mirror and a partial transmission mirror made of a dielectric multilayer film, and An LD-excited solid-state laser oscillator characterized in that a vibrator that generates ultrasonic waves is directly bonded to the other surface.