Sensitivity enhancement of thermal lens spectrometry
Eben Sy Dy, Caikang Gu, Jun Shen, Wei Qu, Zhong Xie, Xiaomeng Wang, Mauro Luciano Baesso, Nelson G. C. Astrath
Abstract
Thermal lens spectrometry has been utilized in various applications, and in some application areas, high sensitivity is required. In this work, a mode-mismatched thermal lens configuration probing thermal lens twice was developed for sensitivity enhancement. Experimental results exhibited that doubled sensitivity was achieved with this configuration compared with that attained with a conventional one, which was consistent with the prediction of the theoretical model for thermal lens spectrometry. As a result of the consistency, the linear absorption (attenuation) coefficient of de-ionized water at 532.3 nm was directly measured with this configuration and the conventional one and found to be (4.90 ± 0.05) × 10−2 m−1 and (4.7 ± 0.2) × 10−2 m−1, respectively. The results are in good agreement with accepted literature values. Theoretical analysis revealed that the sensitivity enhancement with this configuration is greater than that by simply doubling the sample thickness in a conventional configuration.