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Thermal Lens Spectroscopy

Electronic Absorption and Luminescence

  1. Mladen Franko1,
  2. Chieu D. Tran2

Published Online: 15 MAR 2010

DOI: 10.1002/9780470027318.a9079

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Franko, M. and Tran, C. D. 2010. Thermal Lens Spectroscopy. Encyclopedia of Analytical Chemistry. .

Author Information

  1. 1

    University of Nova Gorica, Laboratory of Environmental Research, Nova Gorica, Slovenia

  2. 2

    Marquette University, Department of Chemistry, Milwaukee, WI, USA

Publication History

  1. Published Online: 15 MAR 2010

Abstract

The thermal lens technique is based on measurement of the temperature rise that is produced in an illuminated sample as a result of nonradiative relaxation of the energy absorbed from a laser. Because the technique is based on direct measurement of the absorbed optical energy, its sensitivity is higher than conventional absorption techniques. However, advantages of the thermal lens technique are not only limited to its ultrasensitivity but also include other unique characteristics including small-volume sample capability and dependency on thermo-optical properties of solvents. In this overview, the theory of the technique is initially described. The main focus is, however, on the instrumentation and applications based on unique characteristics of the technique. Specifically, the discussion begins with a description of different types of thermal lens apparatuses (e.g. single-beam and double-beam instruments, differential, multiwavelength, thermal lens-circular dichroism instruments, and thermal lens microscope). A detailed description of various applications including applications based on its ultratrasensitivity (e.g. applications in environment, agriculture and food science, biochemistry and biomedicine, measurements in the near- and middle-infrared region, and kinetic determination), applications based on its small-volume capability (microfluidic devices, detection for capillary electrophoresis), and applications based on exploitation of its dependency on thermal physical properties of solvents to either determine physical properties of the solvent or to further enhance the sensitivity of the technique follows. Finally, the future of the technique is forecasted.

Keywords:

  • thermal lens;
  • lasers;
  • microfluidics;
  • biomedical;
  • environmental;
  • kinetics;
  • near-infrared;
  • organized media