Abstract

Impulse mirage effect spectroscopy is developed in this work as a nondestructive method for depth profiling the optical properties of samples which are nearly thermally homogeneous with depth. Both a theory and an experimental methodology are presented. An inverse scattering theory of the experimental photothermal deflection signal is derived, based on a previous theory of the impulse mirage effect, which takes into account the effect of Fresnel diffraction on the probe beam. To reconstruct the depth profile of heat source density generated by light absorption in an unknown sample, we have applied our inverse theory to the experimental impulse response, using a regularized minimum square error reconstruction algorithm based on our previously published expectation minimum principle. Because this reconstruction problem is ill posed, it was necessary to identify and compensate for all experimental bias errors significantly affecting the fidelity of the depth profiles. A procedure for obtaining the overall best-fit model of the depth profile given the minimum prior experimental information is presented. These procedures have produced an agreement between the experimental and theoretically predicted mirage effect response to within typical root-mean-square error levels of 0.5% or less.

Continuous-wave photothermal deflection spectroscopy with fundamental and harmonic responses

Jianhua Zhao, Jun Shen, and Cheng Hu
Opt. Lett. 27(20) 1755-1757 (2002)

Frequency-modulated impulse response photothermal detection through optical reflectance. 1: Theory

Andreas Mandelis and Joan F. Power
Appl. Opt. 27(16) 3397-3407 (1988)

Graded-index profiles by inversion with Lloyd's mirage

L. J. Allen and R. Lipperheide
Appl. Opt. 35(19) 3496-3499 (1996)

Depth profiles in confocal optical microscopy: a simulation approach based on the second Rayleigh-Sommerfeld diffraction integral

Rosario Esposito, Giuseppe Scherillo, Marianna Pannico, Pellegrino Musto, Sergio De Nicola, and Giuseppe Mensitieri
Opt. Express 24(12) 12565-12576 (2016)

Frequency modulation time delay thermal lens effect spectrometry: a new technique of transient photothermal calorimetry

J. F. Power
Appl. Opt. 29(6) 841-854 (1990)