Paper
29 September 1995 Low-power compact laser-based nonlinear degenerate four-wave mixing detection for flowing liquids
Sandrine Berniolles, Jon A. Nunes, William M. Tong
Author Affiliations +
Abstract
Forward-scattering degenerate four-wave mixing is presented as a sensitive nonlinear laser-based absorbance detection method for room- temperature condensed-phase analytes using compact low-power lasers. In the liquid phase, the signal is generated mainly by the formation of spatial gratings due to thermally-induced refractive index change, resulting from constructive interference between the input beams. This nonlinear laser method offers convenient and efficient optical signal detection since the signal is a coherent beam and it can be collected and measured virtually against a dark background. Since only two input beams are used, the optical alignment is simple compared to other multiphoton methods. The use of a single lens for all the input beams provides tighter focusing and higher wave-mixing efficiency and maximizes photon density available at the sample cell. Hence, laser power requirements are unusually low (<10 mW), allowing the use of portable, low-cost lasers such as He-Ne lasers and diode lasers. Since only a single laser is required, the overall optical setup in this one- color one-laser method can fit in a simple compact package with minimum laser and optics requirements. The detection sensitivity approaches those of laser fluorescence methods, yet this compact nonlinear absorbance detector can detect both fluorescing and nonfluorescing analytes.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Sandrine Berniolles, Jon A. Nunes, and William M. Tong "Low-power compact laser-based nonlinear degenerate four-wave mixing detection for flowing liquids", Proc. SPIE 2546, Optical Techniques in Fluid, Thermal, and Combustion Flow, (29 September 1995); https://doi.org/10.1117/12.221518
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CITATIONS
Cited by 3 patents.
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KEYWORDS
Liquids

Chemical analysis

Semiconductor lasers

Four wave mixing

Signal detection

Nonlinear optics

Capillaries

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