Abstract

This paper describes a differential photothermal optical absorbance apparatus that uses two excitation beams at different wave-lengths. A single probe beam monitors the difference in heats generated by the two wavelengths. The theory is developed for the operational principles of the apparatus, and theoretical signals are compared with those obtained with a conventional absorption spectrophotometer. The differential photothermal apparatus has a theoretical advantage over conventional spectrophotometry for samples with less than unit absorbance. Experiments are described which verify the operating principles and demonstrate the flexibility of the apparatus.

Accounting for absorption saturation effects in pulsed infrared laser-excited photothermal spectroscopy

Stephen E. Bialkowski
Appl. Opt. 32(18) 3177-3189 (1993)

Photothermal deflection spectroscopy and detection

W. B. Jackson, N. M. Amer, A. C. Boccara, and D. Fournier
Appl. Opt. 20(8) 1333-1344 (1981)

Pulsed photothermal deflection spectroscopy in a flowing medium: a quantitative investigation

A. Rose, Reeta Vyas, and R. Gupta
Appl. Opt. 25(24) 4626-4643 (1986)

Application of the BaTiO₃ beam-fanning optical limiter as an adaptive spatial filter for signal enhancement in pulsed infrared laser-excited photothermal spectroscopy

Stephen E. Bialkowski
Opt. Lett. 14(18) 1020-1022 (1989)

Sagnac interferometer for photothermal deflection spectroscopy

Naoyuki Shiokawa, Yuki Mizuno, Harumasa Tsuchiya, and Eiji Tokunaga
Opt. Lett. 37(13) 2655-2657 (2012)