OPTICAL PROBING OF PHOTOACOUSTIC PROPAGATION FOR NONCONTACT MEASUREMENT OF FLOWS, TEMPERATURES AND CHEMICAL COMPOSITIONS

Abstract : Noncontact techniques of optical probing of photoacoustic pulses provide new opportunities for ultrasonic and/or spectroscopic measurement in hostile environments (e.g., flames, corrosive fluids, dangerous aerosols, etc.) and also basic understanding of photoacoustic generation processes. This paper provides examples of such applications in the new field of 'optical ultrasonics' (whereby ultrasonic determinations of flows, temperatures, etc., are measured optically), including 'optical ultrasonic spectroscopy' (whereby ultrasonic dispersion and relaxations are measured optically).