JPH1154836A - Semiconductor laser equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high conversion efficiency by providing a mirror which reflects only a particular wavelength, a wavelength conversion element arranged in a resonator, and a means of taking out light, which is wavelength-converted, to the outside. SOLUTION: A mirror 15 is spread with a coat which yields total reflection with respect to the wavelength of a fundamental wave as an outgoing light from a laser diode chip 10 and has no reflection with respect to the wavelength of a second higher harmonics converted by a nonlinear optical crystal 14. As a result, only the second higher harmonics converted by the nonlinear optical crystal 14 is emitted to the outside of a resonator. By doing this, the second higher harmonics obtained by wavelength conversion can be emitted. Thus, the power density of the fundamental wave inside the nonlinear optical crystal 14 can be easily enhanced, without the use of a complicated structure of an external resonator, etc., and as a result, high conversion efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device suitable for generating short-wavelength laser light, which is used for various purposes such as information equipment, semiconductor manufacturing equipment, and biomedical equipment.

[0002]

2. Description of the Related Art Conventionally, as a device for generating a short-wavelength laser beam, a gas laser device represented by an Ar laser device, a wavelength conversion laser device for an LD-pumped solid-state laser, and wavelength conversion of semiconductor laser light by an external resonator. A known type of laser device is known.

[0003]

However, any conventional laser device for generating short-wavelength laser light has a problem. A gas laser device such as an Ar laser is large, has a short life, and consumes large power. In the case of a wavelength conversion laser device of an LD-pumped solid-state laser and a laser device of a type in which a semiconductor laser beam is wavelength-converted by an external resonator, the device is complicated.
Adjustment and control are extremely difficult.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a semiconductor laser device which is small, lightweight, simple in structure and capable of outputting short-wavelength laser light with high efficiency.

[0005]

In order to achieve the above object, a semiconductor laser device according to the present invention comprises: a semiconductor laser element having a total reflection surface at one end and a non-reflection surface at the other end; A mirror that is disposed outside the element and forms an optical resonator with the one end surface, reflects substantially only light of a specific wavelength, a wavelength conversion element disposed in the resonator, And a means for extracting the wavelength-converted light to the outside.

A laser resonator is formed by one end face of a semiconductor laser element and an external mirror, and a wavelength conversion element is disposed in the laser resonator to output wavelength-converted light to the outside. The structure is simple, high conversion efficiency can be easily obtained, and short-wavelength high-power laser light can be obtained.

[0007]

Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, one end face 11 of a laser diode chip (LD chip) 10 is provided with an HR coating which is a total reflection film for light of an oscillation wavelength, and the other end face 12 is not coated with light of the same wavelength. An AR coat serving as a reflection film is provided. This end face 1
The laser beam emitted from 2 is condensed on the nonlinear optical crystal 14 by the condensing lens 13 and further reflected by the wavelength selective mirror 15 serving as a concave mirror.
The laser beam can be again incident on the laser diode chip 10 by following the same path in reverse. Thereby, a laser resonator is formed by the end face 11 and the mirror 15. The laser beam having the wavelength transmitted through the mirror 15 is collimated by the collimating lens 16 and emitted.

The laser diode chip 10 is mounted on a Peltier element 24 via a heat sink 25 and temperature-controlled, and emits a laser beam of an appropriate wavelength (for example, infrared light having a wavelength of about 860 nm, hereinafter referred to as a fundamental wave). Tuned to occur.

The nonlinear optical crystal 14 converts the wavelength of light passing therethrough. The nonlinear optical crystal 14 is attached to a Peltier element 26 via a heat sink 27 and is controlled at a temperature at which the most efficient wavelength conversion is performed.

The mirror 15 is totally reflected with respect to the wavelength of the fundamental wave which is the light emitted from the laser diode chip 10, and is not reflected with respect to the wavelength of the second harmonic converted by the nonlinear optical crystal 14. As a result, only the second harmonic converted by the nonlinear optical crystal 14 is emitted to the outside of the resonator. Thereby, the second harmonic (for example, wavelength 4
Blue light around 30 nm) can be emitted.

The laser diode chip 10, the condensing lens 13, the nonlinear optical crystal 14, the wavelength selective mirror 15, and the collimating lens 16 are directly connected to the base 21 via a heat sink or a Peltier element or not. Is fixed on a heat sink 23 attached via a Peltier device 22 so that the entire device is maintained at a constant temperature by the Peltier device 22.

In such a configuration, the resonator of the semiconductor laser device is connected to one end face 1 of the laser diode chip 10.
1 and an external mirror 15, the nonlinear optical crystal 14 is arranged in the resonator, the wavelength is converted, and only the light of the converted wavelength is emitted to the outside. for that reason,
The power density of the fundamental wave in the nonlinear optical crystal 14 can be easily increased without using a complicated structure such as an external resonator, and as a result, high conversion efficiency can be obtained. That is, the semiconductor laser device configured as described above is small and lightweight, and can generate short-wavelength laser light with high efficiency.

FIG. 2 shows another embodiment, in which a laser resonator is formed by one end face 11 of a laser diode chip 10 and a total reflection mirror 19. In this resonator, a nonlinear optical crystal 14 and a prism 18 are provided.
Are arranged, the wavelength is converted by the nonlinear optical crystal 14, and the fundamental wave and the second
Wavelength selection from harmonics. Since the wavelength is selected by the prism 18, the mirror 19 is not a wavelength selectable but a total reflection mirror. By changing the angle of the mirror 19 and changing the wavelength of the light returning to the resonator as shown by the arrow, the oscillation wavelength of the fundamental wave can be tuned. It is possible to make the wavelength of the obtained second harmonic variable.

Although not shown in FIG. 2, the temperature of the laser diode chip 10 and the nonlinear optical crystal 14 are controlled by fixing them via a heat sink and a Peltier element as in FIG. It is desirable that other optical elements be fixed to the base 21 via the heat sink 23 and the Peltier element 22 as shown in FIG.

The above description relates to one embodiment of the present invention, and the present invention is not limited to the above, and can be variously modified without departing from the spirit of the present invention. . For example, in FIG. 2, the wavelength can be tuned using an etalon or a grating instead of the prism 18.

[0016]

As described above, according to the semiconductor laser device of the present invention, the laser resonator is formed by one end face of the semiconductor laser element and the external mirror, and the laser resonator is formed therein. Since a nonlinear optical crystal is arranged to output the wavelength-converted light to the outside, the structure is simple, high conversion efficiency can be easily obtained, and a small, lightweight, high-power short-wavelength laser light can be obtained. Output can be performed with high efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laser diode chip 11 End face which is a total reflection surface 12 End face which is a non-reflection surface 13, 17 Condensing lens 14 Nonlinear optical crystal 15 Wavelength selective concave mirror 16 Collimating lens 18 Prism 19 Total reflection mirror 21 Base 22, 24, 26 Peltier device 23, 25, 27 Heat sink

Claims (1)

[Claims] 1. An optical resonator is formed between a semiconductor laser element having a total reflection surface at one end surface and a non-reflection surface at the other end surface, and the one end surface disposed outside the semiconductor laser device. A semiconductor laser device comprising: a mirror for reflecting substantially only light of a specific wavelength; a wavelength conversion element disposed in the resonator; and means for extracting the wavelength-converted light to the outside. .