Optical beam deflection thermal imaging

A method of thermal imaging comprising the steps of:

• applying energy to a sample to produce a spatially localized area on the sample surface having a radial surface temperature gradient, said radial surface temperature gradient produces in a fluid adjacent to said sample surface, a localized volume having an alternating refractive index;
• directing an optical probe beam through at least one of a plurality of positions, each position having a different transverse offset value (.DELTA.) measured from the point of intersection with said narrow beam excitation means and passing through said volume of alternating refractive index which causes said optical probe bean to be deflected;
• and,
• measuring the transverse deflection (.psi..sub.t) of said optical probe beam for said at least one of a plurality of transverse offset values (.DELTA.) to provide information on properties and features at the surface and subsurface layers of said sample.

A method of thermal imaging comprising the steps of:

• directing an excitation beam to the surface of a sample for generating a spatially localized area on the sample surface having a radial surface temperature gradient;
• directing an optical probe beam through at least one of a plurality of positions, each position having a different transverse offset value (.DELTA.) measured from the point of intersection with said narrow beam excitation means, and passing through a thermal lens produced adjacent to said sample by said radial surface temperature gradient;
• and,
• measuring the transvere deflection (.psi..sub.t) of said optical probe beam for said at least one of a plurality of transverse offset values (.DELTA.) to provide information on properties and features at the surface and subsurface layers of said sample.