Analytical solution for mode-mismatched thermal lens spectroscopy with sample-fluid heat coupling

Abstract

This paper presents an improved theoretical description of the mode-mismatched thermal lens effect using models that account for heat transport both within the sample and out to the surrounding coupling medium. Analytical and numerical finite element analysis (FEA) solutions are compared and subsequently used to model the thermal lens effect that would be observed using continuous laser excitation. FEA model results were found to be in excellent agreement with the analytical solutions. The model results show that heat transfer to the air coupling medium introduces only a minor effect when compared with the solution obtained without considering axial air-sample heat flux for practical examples. On the other hand, the thermal lens created in the air coupling fluid has a relatively more significant effect on the time-dependent photothermal lens signals.

Physical origin of observed nonlinearities in Poly (1-naphthyl methacrylate): Using a single transistor—transistor logic modulated laser beam

“…Using Eqs. (3)- (7), the values for D, n 2 , dn/dT , and ∆n are calculated and shown in Table 1. Table 1.…”

“…In addition, it was used in two different techniques, the mode matched thermal lens [5,6] and the mode mismatched thermal lens spectropies. [7] It was used in a variety of applications such as scanning microscopy, [8] food analysis, and environmental research, [9,10] realization of optical logical gates, [11] measurements in microchips, [12] microchemical chips, [13] complex fluids, [14] investigation of the quantum yield, [15,16] ion chromatography, [17] and determination of iodine. [18] Changes in refractive index induced by an optical field can give rise to various nonlinear phenomena in optical materials.…”

Analysis of the Thermo-Reflectivity Coefficient Influence Using Photothermal Pump–Probe Techniques

“…9,10 Heat coupling between sample and surrounding adjacent medium has also been considered and led to new applications. 11,12 Nevertheless, the influence of reflectivity change due the temperature variation was never specifically analyzed with regard to its contribution to the photothermal signal.…”