Robert V Goedert

US Patent:

56045883, Feb 18, 1997

Filed:

Jul 20, 1995

Appl. No.:

8/505519

Inventors:

Robert V. Goedert - Ferndale MI

Assignee:

United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01N 2163

US Classification:

356318

Abstract:

A method to examine laser induced plasma or bubble formations in nonlinear limiter cells includes splitting a laser pulse into an initiation pulse, a first probe pulse and a second probe pulse. The initiation pulse is focussed at a site in the cell, so that a formation of interest occurs there. The probe pulses are converted to frequencies different from each other and different from the initiation pulse frequency. Then the probe pulses are sent through single mode fibers of different measured lengths, so that the probe pulses are retarded relative to the initiation pulse by different, controlled intervals. The probe pulses exit the fibers in coherent collimated condition and travel along a common path crossing the site. The initiation pulse will have arrived at the site and created the formation before the first probe pulse arrives, and the second probe pulse arrives at the site after the first probe pulse. Shadowgraphs resulting from passage of the probe pulses past the formation are then imaged.