
Accession Number : AD0715937
Title : Track Formation in Optical Glass Caused by Electrostrictive Laser Beam SelfFocusing.
Descriptive Note : Doctoral thesis,
Corporate Author : PERKINELMER CORP WILTON CONN
Personal Author(s) : Kerr,Edwin L.
Report Date : OCT 1970
Pagination or Media Count : 139
Abstract : An electrostriction mechanism for laser beam selffocusing and track formation in transparent optical glass is analyzed theoretically. Electrostrictive selffocusing occurs when a laser pulse of sufficiently high power and rapid rise time passes through a transparent medium. During selffocusing, the beam collapses to a small radius, leaving a track of permanent damage. Typical tracks have a diameter of a few wavelengths of light and extend up to several centimeters. The propagation of the beam is described by a new 'smallscale' beam tracing equation, derived from Maxwell's equations. The equation includes the effect of the inhomogeneous index term of the vector light wave equation as well as beam diffractive. For steadystate Kerr and electrostrictive trapping, the new equation gives experimentally correct filament diameters. A trapping threshold is derived for three pulse shapes, covering the steadystate, transitional, and transient regimes of pulse duration and beam size. A formula for computing the power to achieve a given maximum intensity is derived. A computer movie of beam trapping shows the collapse of the beam during selffocusing. (Author)
Descriptors : (*OPTICAL GLASS, DAMAGE), (*LIGHT PULSES, TRACKING), ELECTROSTRICTION, FRACTURE(MECHANICS), MATHEMATICAL MODELS, LASERS, FOCUSING, THESES, (U)THESES
Subject Categories : Lasers and Masers
Optics
Distribution Statement : APPROVED FOR PUBLIC RELEASE