Solid-state laser apparatus

Details Solid-state laser apparatus Solid-state laser apparatus

1999-06-08

2001-02-13

Healy, Brian (Department: 2874)

Coherent light generators

Particular resonant cavity

Specified cavity component

C372S098000, C372S075000, C372S019000, C372S108000, C372S039000

Reexamination Certificate

active

06188713

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a solid-state laser apparatus for exciting a solid-state laser medium placed inside a resonator with a beam of pump light from an appropriate source and thereby causing a beam of laser light to be emitted from the resonator.
In order that the transverse mode of the laser beam generated by such an apparatus be a single transverse mode (TEM
00
), it has been know to make the pump light incident such that its transverse (pumping) mode coincides with the resonator mode of the solid-state laser medium or is included in the resonator mode. It is not a simple matter, however, to focus the pump light such that all of its pumping modes will be incident within the resonator mode in the solid-state laser medium because a complicated optical system will be required for the purpose. A particularly complicated optical system will be necessary if a semiconductor laser element is used as the source of pump light for the solid-state laser apparatus because the transverse mode of laser light from a semiconductor laser element is an elongated ellipse either because the stripe of active layer of a semiconductor laser element for emitting laser light is about 1&mgr;m in thickness while its width is about 100 &mgr;m or due to astigmatism. Thus, a complicated optical system using a complicated lens such as an anamorphic prism pair or a cylindrical lens or a large number of lenses is required in order to change this shape into a true circle and to focus it within an area with a smaller diameter than that of the resonator mode. In order to obtain a high-power emission of solid-state laser light, the width of the stripe of the active layer of the semiconductor laser element must be increased with respect to its thickness, but this will make the transverse mode of the emitted laser light much flatter, and an even more complicated optical system will be necessary. If a complicated optical system is incorporated, not only the size of the solid-state laser apparatus itself but also the energy loss of the pump light will become large, making it economically disadvantageous.
In the case of a quasi-three-level laser system, furthermore, there is the big problem of reabsorption, or the absorption by the laser medium of the fluorescent light generated by spontaneous emission when the electrons excited by the pump light drop to lower energy levels, as well as the laser light which has just come to be emitted. Unless the pump light remains incident on the resonator mode in the solid-state laser medium, the reabsorbed energy is converted into heat, thereby raising the threshold for the laser light emission.
SUMMARY OF THE INVENTION
It is therefore an object of this invention in view of the problems described above to provide a solid-state laser apparatus with a simple structure capable of emitting laser light in a single transverse mode.
A solid-state laser apparatus embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising a solid-state laser medium inside a resonator, a pump light source such as a semiconductor laser apparatus which generates pump light, and an optical system for focusing the pump light on the solid-state medium such that its distribution is not only inside but also at least in part outside the resonator mode in the solid-state laser medium, say, over more than 50% of the total length of the solid-state laser medium.


REFERENCES:
patent: 4426707 (1984-01-01), Martin et al.
patent: 4564268 (1986-01-01), Tatsuno et al.
patent: 4779278 (1988-10-01), McKinney
patent: 4942586 (1990-07-01), Lai
patent: 5140608 (1992-08-01), Karpol et al.
patent: 5268920 (1993-12-01), Esterowitz et al.
patent: 5278851 (1994-01-01), Goto
patent: 5349600 (1994-09-01), Shinbori et al.
patent: 5349603 (1994-09-01), Kaneda et al.
patent: 5651020 (1997-07-01), Nighan, Jr. et al.
patent: 5692005 (1997-11-01), Maag et al.
patent: 5982806 (1999-11-01), Yamaguchi et al.
patent: 6061382 (2000-05-01), Govorkov et al.

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