Applications of thermoreflectance imaging to high-power diode laser diagnostics

Thermoreflectance imaging enables noncontact mapping of surface temperature with high spatial resolution and high temperature resolution in electronic and optoelectronic devices. Recently we have applied charge-coupled device (CCD) based thermoreflectance imaging to study facet heating in high-power diode lasers. Sources of facet heating we have examined include back-irradiance as well as optical absorption of laser light at the outcoupling facet prior to emission. For the latter we have combined temperature measurements with a thermal model to derive facet optical absorption and have studied its evolution as the device ages.