Real-time measurement of nano-particle size using differential optical phase detection

We demonstrate a size sensing technique for nano-particles using optical differential phase measurement by a dual fiber interferometer through phase-generated carrier (PGC) demodulation. Nano-particle diameters are obtained from the differential phase shift as a result of adding an optical scatterin...

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Bibliographic Details
Main Authors: Lin, Feng, Wu, Xingkun, Li, Qing, Huang, He
Other Authors: School of Computer Science and Engineering
Format: Article
Language:English
Published: 2018
Subjects:
Online Access:https://hdl.handle.net/10356/88862
http://hdl.handle.net/10220/45994
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Institution: Nanyang Technological University
Language: English
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Summary:We demonstrate a size sensing technique for nano-particles using optical differential phase measurement by a dual fiber interferometer through phase-generated carrier (PGC) demodulation. Nano-particle diameters are obtained from the differential phase shift as a result of adding an optical scattering perturbation into two-beam interference. Polystyrene nano-particles with diameters from 200 to 900 nm in a microfluidic channel are detected using this technique to acquire real-time particle diameters. Compared with amplitude sensing with over 10 mW of laser irradiance, particle sizing by PGC phase sensing can be achieved at a laser power as low as 1.18 mW. We further analyze major sources of noise in order to improve the limits of detection. This sensing technique may find a broad range of applications from the real-time selection of biological cell samples to rare cell detection in blood samples for early cancer screening.