Development of a desktop-sized thermal lens microscope

Abstract

A desktop-sized thermal lens microscope (DT-TLM) having high sensitivity and wide applicability was developed. The operationality of the DT-TLM compared with that of a big-sized TLM has been remarkably improved by simplifying the optics and optimizing the optical configuration. In order to evaluate the performance, the DT-TLM was applied to the ultrasensitive detection of a non-fluorescent molecule (dye: Sunset Yellow) in water. The concentration dependence of the thermal lens signal (calibration curve) showed good linearity in the range of 1 × 10-8-1 × 10-7 M. From the value of twice the standard deviation (2σ) of this calibration curve, the lower limit of the quantitative determination was estimated to be 1.10 × 10-8 M. The lower limit of detection was estimated as 8.27 × 10-9 M from the conditions of the signal-to-noise ratio S/N = 2. These obtained values were almost the same as that of the big-sized TLM.