Influence of the sample-probe coupling on the resolution of transmitted near-field optical image

In this work we examine the time-dependent aspects of thermal imaging of buried metallic and non-metallic objects, when impulse heating of the soil surface is performed. A 1500W carbon dioxide laser is used to provide the thermal impulse. Time-dependent thermal images arc obtained using an infrared focal plane array camera and a gated data acquisition/analysis system. Experimental studies are conducted as a function of object material, size, and burial depth, and incident laser fluence. Quantitative evaluation of the surface temperature differen tials as a function of time are presented.