David D Meyerhofer

US Patent:

50954873, Mar 10, 1992

Filed:

Dec 14, 1990

Appl. No.:

7/627661

Inventors:

David D. Meyerhofer - Spencerport NY
Ansgar W. Schmid - Honeoye Falls NY
Yung-ho Chuang - Rochester NY

Assignee:

The University of Rochester - Rochester NY

International Classification:

H01S 3082

US Classification:

372 23

Abstract:

Ultra short (pico second and shorter) laser pulses having components of different frequency which are overlapped coherently in space and with a predetermined constant relationship in time, are generated and may be used in applications where plural spectrally separate, time-synchronized pulses are needed as in wave-length resolved spectroscopy and spectral pump probe measurements for characterization of materials. A Chirped Pulse Amplifier (CPA), such as a regenerative amplifier, which provides amplified, high intensity pulses at the output thereof which have the same spatial intensity profile, is used to process a series of chirped pulses, each with a different central frequency (the desired frequencies contained in the output pulses). Each series of chirped pulses is obtained from a single chirped pulse by spectral windowing with a mask in a dispersive expansion stage ahead of the laser amplifier. The laser amplifier amplifies the pulses and provides output pulses with like spatial and temporal profiles.

US Patent:

61413623, Oct 31, 2000

Filed:

Jun 5, 1998

Appl. No.:

9/092053

Inventors:

David D. Meyerhofer - Spencerport NY
Oleg A. Konoplev - Rochester NY

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

H01S 313

US Classification:

372 30

Abstract:

A pulsed laser is provided wherein the B-integral accumulated in the laser pulse is reduced using a semiconductor wafer. A laser pulse is generated by a laser pulse source. The laser pulse passes through a semiconductor wafer that has a negative nonlinear index of refraction. Thus, the laser pulse accumulates a negative B-integral. The laser pulse is then fed into a laser amplification medium, which has a positive nonlinear index of refraction. The laser pulse may make a plurality of passes through the laser amplification medium and accumulate a positive B-integral during a positive non-linear phase change. The semiconductor and laser pulse wavelength are chosen such that the negative B-integral accumulated in the semiconductor wafer substantially cancels the positive B-integral accumulated in the laser amplification medium. There may be additional accumulation of positive B-integral if the laser pulse passes through additional optical mediums such as a lens or glass plates. Thus, the effects of self-phase modulation in the laser pulse are substantially reduced.