JPH03209786A - Solid-state laser device - Google Patents

Abstract

PURPOSE:To obtain a stable laser output by controlling the electric current of a thermo-element so that the temperature of a solid-state laser crystal can be maintained at a fixed level and detecting the laser light from the crystal, and then, controlling the output of the laser light for excitation so as to maintain the detecting output at a fixed level. CONSTITUTION:Output laser light 10 fetched through an output mirror 9 is inputted to a beam splitter 20 which leads a portion of the laser output 10 to a laser light output detector 30. The detector 30 detects the output of the laser light 10 and feeds back the detected value to an excitation laser controller 40. The controller 40 lowers the output 11 of a laser source 1 for excitation when the laser light 10 increases and raise the output 11 when the laser light 10 decreases so that the measured value inputted from the detector 30 can be maintained at a fixed level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state laser device in which a wavelength-tunable solid-state laser crystal is cooled to obtain stable laser output.

[Conventional technology]

A conventional solid-state laser device is shown in FIG.

This solid-state laser device has T 1: A 1205, C
o: MgF2, Ti: BeAl2O4, Cr: La3
It has a wavelength tunable solid state laser crystal 5 such as Ga5SiOla, Cr:LiCaAlF6, etc., and by irradiating this solid state laser crystal 5 with the laser light 11 of the excitation laser source 1, a desired laser light is emitted from the fixed laser crystal 5. output. That is, the excitation laser beam 11 output from the excitation laser source 1 is focused by the lens 2, passes through the total reflection mirror 3, and is irradiated onto the solid-state laser crystal 5. The total reflection mirror 3 has high transmittance for the wavelength of the excitation laser beam 11, but the output laser beam 1 of the solid-state laser crystal 5
It has high reflectivity for wavelengths of zero.

Therefore, the light emitted from the solid-state laser crystal 5 is amplified by stimulated emission in a resonator 12 constituted by the total reflection mirror 3 and the output mirror 9, and is extracted as a laser output 10 via the output mirror 9.

In this device, a solid-state laser crystal 5 heated by an excitation laser beam 11 is directly cooled by a thermoelectric element 4.

In this cooling control, the temperature of the solid-state laser crystal 5 is measured by a temperature sensor 7 in contact with the solid-state laser crystal 5, and the measured value is fed back to the thermoelectric element controller 6, so that the temperature is applied to the thermoelectric element 4. Temperature control is performed to keep the temperature of the solid-state laser crystal 5 constant by controlling the current value.

Note that the wavelength of the laser output 10 is tuned by a wavelength tuning element such as a birefringence filter installed within the resonator 12.

[Problems to be solved by the invention]

In this prior art, the solid-state laser crystal 5 is cooled by the thermoelectric element 4, and temperature control is performed to keep the temperature of the solid-state laser crystal 5 constant, thereby eliminating fluctuations in the laser output 10.

However, in this prior art, the excitation laser beam 11
When output fluctuation occurs, the laser output 1 of the solid-state laser crystal 5 decreases even if the output stabilization control is performed by the temperature control.
However, there is a problem in that output fluctuations occur and stable output control becomes impossible. That is, it is difficult to keep the laser output 10 from the solid-state laser crystal 5 stable only by controlling the temperature of the solid-state laser crystal 5.

The present invention aims to obtain more stable laser output from a solid-state single-noser crystal.

[Means for solving problems]

In order to achieve the above object, the solid state laser device of the present invention includes a thermoelectric element that cools the solid laser crystal, and a temperature control that controls the current of the thermoelectric element so that the temperature of the solid laser crystal becomes a constant temperature. means, a laser output detection means for detecting the output of the laser light from the solid-state laser crystal, and a control means for controlling the output of the excitation laser light so as to keep the detection output of the laser output detection means constant. I'm trying to prepare.

[Effect]

According to the configuration of the present invention, in addition to constant temperature control of the thermoelectric element, output adjustment control of the excitation laser light is performed using the output 1 noser light of the solid-state laser crystal as a feedback input.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and components that perform the same functions as those of the prior art shown in FIG. 2 are given the same reference numerals, and redundant explanations will be omitted.

That is, in the embodiment shown in FIG. 1, the configuration shown in FIG. 2 includes a beam splitter 20.degree. laser light output detector 30. Also, an excitation laser controller 40 is added.

In this device, the output laser beam 1o taken out via the output mirror 9 is input to the beam splitter 20, and a part of the laser output 10 is guided to the laser beam output detector 30 by the beam splitter 2o. I have to.

The laser light output detector 30 detects the output of the laser light 10 and inputs the detected value as feedback to the excitation laser controller 40 for controlling the excitation laser output 11.

In the excitation laser controller 40, the manually operated detector 3
The measured value of 0 is constantly monitored, and the output of the excitation laser source 1 is adjusted so that this measured value takes a constant value. That is, in this control, when the laser beam 10 increases, the output 11 of the excitation laser source 1 is decreased, and when the laser beam 10 decreases, the output 11 of the excitation laser source 1 is increased.

Note that the quantitative relationship between the laser output 10 of the solid-state laser crystal 5 and the output of the excitation laser source 1 may be determined in advance by experiment.

Thus, in this embodiment, the solid state laser crystal 5
In addition to constant temperature control, the excitation laser light source 1 uses the output laser light 10 of the solid-state laser crystal 5 as a feedback input.
Since the output adjustment control is performed, the output fluctuation of the laser output 10 of the solid-state laser crystal 5, which occurred when only the temperature constant control of the solid-state laser crystal 5 was performed, has been reduced from ±3% to ±0.1.
% or less, and a more stable laser output of 10 could be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, in addition to constant temperature control of the solid-state laser crystal, the output of the excitation laser beam is adjusted using the output laser beam of the solid-state laser crystal as a feedback input, so that the laser output This makes it possible to reduce fluctuations in laser output and obtain stable laser output.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. Figure 2 shows
1 is a schematic diagram showing a conventional technique. 1... Laser source for excitation, 2... Lens, 3... Total reflection mirror 4...
Thermoelectric element, 5... Solid laser crystal, 6... Thermoelectric element controller, 7... Temperature sensor, 8... Wavelength tuning element, 9... Output mirror 10... Laser output, 1
1... Laser light for excitation, 12... Resonator, 20...
・Beam splitter, 30...laser light output detector,
40 excitation laser controller

Claims (1)

[Scope of Claims] A solid-state laser device having a solid-state laser crystal that outputs laser light by being excited by an excitation laser light, comprising: a thermoelectric element that cools the solid-state laser crystal; and a thermoelectric element that cools the solid-state laser crystal; temperature control means for controlling the current of the thermoelectric element so that the temperature is constant; laser output detection means for detecting the output of laser light from the solid-state laser crystal; and a detection output of the laser output detection means to be constant. A solid-state laser device comprising: control means for controlling the output of the excitation laser beam so as to maintain the output of the excitation laser beam.