Laser apparatus

Details Laser apparatus Laser apparatus

1989-05-23

1990-12-11

Scott, Jr., Leon

Coherent light generators

Particular beam control device

Optical output stabilization

372 29, 372 58, 372 59, 372 20, 356352, H01S 313

Patent

active

049775634

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND ART

FIG. 1 is a schematic view showing a conventional wavelength tunable laser apparatus of the type mentioned, for example, in "Applied Optics", July 1974, vol. 13, No. 7, pp. 1625-1628. In the figure, the reference numeral 1 denotes a laser oscillator which is, in this case, a dye laser. The numeral 2 denotes a partially reflecting mirror, 3 a Fabry-Perot etalon (hereinafter abbreviated as "FP") provided with a gap, 4 a closed vessel in which the FP 3 is hermetically sealed with a gas, 5 a laser beam, 6 a pressure gauge for measuring the level of gas pressure inside the closed vessel 4, 7 and, 8 valves, and 9 a grating.
The operation will next be explained. The laser beam emitted from the laser oscillator 1 has a wavelength selected by various elements incorporated in the oscillator. In this prior art, the range of wavelengths is narrowed by means of spectroscopic elements, that is, the grating 9 and the FP 3, which are inserted in the resonator. Moreover, by adjusting these spectroscopic elements, it is possible to set the wavelength at a desired one within the range of oscillation wavelengths that have been present from the outset.
In this prior art, wavelength selection is effected by changing the angle of inclination of the grating 9 and further changing the gas pressure inside the closed vessel 4 to thereby vary the refractive index of the gas in the gap provided in the FP 3. Coarse adjustment of the wavelength can be effected by changing the angle of inclination of the grating 9, and fine adjustment of the wavelength can be achieved by adjusting the gas pressure in the gap of the FP 3. The adjustment of the gas pressure is effected by measuring the level of pressure with the pressure gauge 6 and opening or closing the valves 7 and 8.
The conventional laser apparatus which is arranged in the manner described above has the problem that it is necessary to use a pressure gauge which has a degree of accuracy of, for example, better than 0.1% of the full scale in order to perform wavelength tuning with high precision, e.g., tolerances of .+-.0.001 nm.


DISCLOSURE OF INVENTION

The laser apparatus according to the present invention is arranged such that an etalon is hermetically sealed with a gas and the gas pressure is changed with a feedback signal obtained by monitoring the laser beam, thereby effecting wavelength tuning and wavelength stabilization.


BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a conventional apparatus;
FIG. 2 is a block diagram showing one embodiment of the laser apparatus according to the present invention;
FIG. 3 is a chart showing the fringe intensity distribution on the imaging element 22;
FIG. 4 is a block diagram showing another embodiment of the present invention; and
FIG. 5 is a block diagram showing still another embodiment.


BEST MODE FOR CARRYING OUT THE INVENTION:

One embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, the reference numerals 1 to 4 denote elements which are the same as those of the prior art. The wavelength tuning Fabry-Perot etalon (hereinafter abbreviated as "FP") 3 is accommodated in the closed vessel 4. The reference numeral 10 denotes a totally reflecting mirror which is disposed so as to face the partially reflecting mirror 2 across the FP 4, 11 a volume expanding and contracting means constituted by a bellows which is connected to the closed vessel 4, 12 a mechanism for driving the volume expanding and contracting means 11, 13 a laser beam emitted by the laser oscillator 1 via the totally reflecting mirror 10, the partially reflecting mirror 2 and the FP 3, 14 a beam takeout mirror for taking out a part of the laser beam 13, and 15 a wavelength monitor mechanism which subjects the laser beam taken out by the beam takeout mirror 14 to spectroscopic analysis. The wavelength monitor mechanism 15 comprises an interference filter 16 which passes only the laser beam 13, a filter 17 for adjustment of light intensity, an integrator 18 for diffusing the laser beam 13

REFERENCES:
patent: 3534289 (1970-10-01), Clark et al.
patent: 4097818 (1978-06-01), Manoukian et al.
patent: 4152674 (1979-05-01), Taguchi
patent: 4743114 (1988-05-01), Crane
patent: 4914662 (1990-04-01), Nakatani et al.

Affiliated with

Also associated with

Rating

Laser apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Laser apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laser apparatus will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-393971