STEADY-STATE THERMO-REFLECTANCE METHOD amp; SYSTEM TO MEASURE THERMAL CONDUCTIVITY

摘要

A method of measuring thermal conductivity of a material includes aiming a modulated pump laser beam having a modulation frequency low enough to induce a cyclical steady-state temperature rise having "on" and "off' state at a spot of a material, aiming a CW probe laser beam at the spot and generating a reflected probe beam reflected from the spot on the material, the reflected probe beam having a magnitude of a reflectance signal as a function of the temperature of the material and being periodic corresponding to the cyclical temperature rise, measuring the pump power difference and the reflectance signal magnitude difference between the "on" and "off" states, and calculating the thermal conductivity by fitting the measured power difference and the measured reflectance signal magnitude difference to a thermal model which is a function of a thermal conductivity of the material relating the heat flux to the temperature rise.