Coherent light generators – Particular beam control device – Optical output stabilization
Patent
1988-08-03
1990-10-02
Scott, Jr., Leon
Coherent light generators
Particular beam control device
Optical output stabilization
307427, 372 22, H01S 313
Patent
active
049611950
ABSTRACT:
In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temoral oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation.
REFERENCES:
patent: 4346314 (1982-08-01), Craxton
Veron et al., "Optical Spatial Smoothing of Nd-Glass Laser Beam"; Optics Comm. vol. 65, No. 1, 1 Jan. 1988.
LLE Review, Quarterly Report, vol. 33, Oct.-Dec., 1987, ed., J. Kelly, pp. 1-10.
Y. Kato et al., Phys. Rev., Lett., 53, 1057 (1984).
R. H. Lehmberg et al., Opt. Commun., 46, 27 (1983).
S. P. Obenschain et al., Phys. Rev. Lett., 56, 2807 (1986).
R. H. Lehmberg et al., J. Appl. Phys., 62, 2680 (1987).
R. H. Lehmberg et al., Fusion Tech. 11, 532 (1987).
R. S. Craxton et al., IEEE J. Quantum Electron., QE-17, 1771 (1981).
R. C. Eckardt et al., IEEE J. Quantum Electron., QE-20 1178 (1984).
LL Review, Quarterly Report, vol. 25, Oct-Dec. 42, 1984, Ed. A. Schmid.
IEEE Journal of Quantum Electron, vol. QE-17, 1782, Sep. 1981, Craxton et al.
IEEE J. Quantum Electronics, QE-5, 484 (1969) E. B. Tveacy.
Craxton R. Stephen
Skupsky Stanley
Soures John
Jr. Leon Scott
Lukacher Martin
The University of Rochester
LandOfFree
Systems for controlling the intensity variations in a laser beam does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Systems for controlling the intensity variations in a laser beam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Systems for controlling the intensity variations in a laser beam will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-296253