Remote and autonomous temperature measurement based on 3D liquid-crystal microlasers

Gregor Pirnat; Matjaž Humar; Igor Muševič

doi:10.1117/12.2508511

1 March 2019 Remote and autonomous temperature measurement based on 3D liquid-crystal microlasers

Gregor Pirnat, Matjaž Humar, Igor Muševič

Proceedings Volume 10941, Emerging Liquid Crystal Technologies XIV; 109410A (2019) https://doi.org/10.1117/12.2508511
Event: SPIE OPTO, 2019, San Francisco, California, United States

Abstract

We demonstrate non-contact temperature measurement with 0.1 K precision at distances of several meters using omnidirectional laser emission from dye-doped cholesteric liquid crystal droplets freely floating in a fluid medium. Upon the excitation with a pulsed laser the liquid crystal droplet emits laser light due to 3D Bragg lasing in all directions. The spectral position of the lasing is highly dependent on temperature, which enables remote and contact-less temperature measurement with high precision. Both laser excitation and collection of light emitted by microlasers is performed through a 20 cm aperture optics at a distance of up to several meters. The optical excitation volume, where the droplets are excited and emit the laser light, is approx. 10 cubic millimeters. The measurement is performed with sub-second speed when several droplets pass through the excitation volume due to their thermal motion. Since the method is based solely on measuring the spectral position of a single and strong laser line, it is quite insensitive to scattering, absorption and background signals, such as auto-fluorescence. This enables a wide use in science and industry, with a detection range exceeding tens of meters.

Citation Download Citation

Gregor Pirnat, Matjaž Humar, and Igor Muševič "Remote and autonomous temperature measurement based on 3D liquid-crystal microlasers", Proc. SPIE 10941, Emerging Liquid Crystal Technologies XIV, 109410A (1 March 2019); https://doi.org/10.1117/12.2508511

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