Opto-Thermal Spectroscopy

Abstract

About a decade ago, the first opto-thermal spectrometer was developed by Gough, Miller and Scoles [1] at the Waterloo University. The basic idea of this technique is to use a cryogenic thermal detector (bolometer) for measuring the internal energy of a supersonic molecular beam. When the molecular beam is illuminated by means of resonant radiation, the internal state of molecules may change and the corresponding energy variation is detected by means of the bolometer. Up to now opto-thermal methods have found application in the following fields:

• molecular beam diagnostics and internal state preparation;

• sub-Doppler infrared spectroscopy;

• photodissociation spectroscopy of dimers and clusters;

• spectroscopy of highly excited vibrational states (multiphoton excitations, overtone and combination bands).