New opto-thermal radiometry technique using wavelength-selective detection

The authors report the development of a new opto-thermal radiometry technique, using wavelength-selective detection. The measurement principle is similar to that of opto-thermal transient emission radiometry (OTTER), but includes a grating monochromator as part of the signal detection system, to enable opto-thermal transients at selected infrared wavelengths to be studied. The technique offers the ability to separate the effects associated with the absorption of exciting light from those of infrared emission. Changes of opto-thermal decay time with emission wavelength can therefore be related to the infrared absorption spectrum of the sample. First observations on TiO2 excited by UV laser light are presented.