Elsevier

Sensors and Actuators B: Chemical

Volume 241, 31 March 2017, Pages 1145-1152
Sensors and Actuators B: Chemical

On the effects of the time gate position and width on the signal-to-noise ratio for detection of Raman spectrum in a time-gated CMOS single-photon avalanche diode based sensor

https://doi.org/10.1016/j.snb.2016.10.021Get rights and content
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Highlights

  • Signal-to-noise ratio optimization in time-gated Raman spectroscopy is proposed.

  • The optimum time gate depend on the ratio of Raman to fluorescence photons.

  • Acceptable timing in-homogeneities of 2-D SPAD detector arrays can be estimated.

Abstract

The effects of the position and width of the time gate on the available signal-to-noise ratio in a time-gated Raman spectrometer are analyzed and measured. The Raman spectrometer used is based on a high power, 532 nm, pulsed laser (500 ps FWHM) and a time-resolving circuit with a single photon avalanche diode (SPAD) detector which is moved by a microstep motor to derive the whole Raman spectrum. The times of arrival of the scattered photons are recorded and the effectiveness of different time gate positions and widths are analyzed by post-processing the measured and simulated data. It is shown from measurements performed on olive and sesame seed oil samples having fluorescence lifetimes of 2.5 ns and 2 ns and Raman-to-fluorescence photon ratios of 0.03 and 0.003, respectively, that the fluorescence background can be substantially suppressed if the width and position of the time gate are properly selected.

Keywords

SPAD detector
Raman spectroscopy
Time gating
Single photon counting

Cited by (0)

Ilkka Nissinen (M’09) was born in Oulu, Finland, in 1976. He received the M.Sc. Eng., Licentiate of Tech. and Dr. Tech. degrees in electrical engineering from the University of Oulu, Finland, in 2002, 2007 and 2011, respectively. He has been Research Scientist in 2002–2011 and Postdoctoral Researcher since 2011 in Circuits and Systems Research Unit in University of Oulu. His research interests include the design of time interval measurement architectures for the integrated receiver of pulsed time-of-flight laser rangefinders and the development of time-gated single photon avalanche diode arrays for Raman spectroscopy. He has designed or co-designed approximately 10 ASICs during his career and has authored or co-authored 24 scientific papers.

Jan Nissinen was born in Oulu, Finland, in 1976. He received the M.Sc. Eng., Licentiate of Tech. and Dr.Tech. degrees in electrical engineering from the University of Oulu, Finland, in 2002, 2007 and 2011, respectively. He has been Research Scientist in 2002–2011 and Postdoctoral Researcher since 2011 in Circuits and Systems Research Unit in University of Oulu. His research interests include the design of analog and mixed-signal integrated circuits for pulsed time-of-flight laser rangefinders and for pulsed Raman spectroscopy.

Pekka Keränen was born in Tampere, Finland, in 1985. He received the M.Sc. (Tech) and Dr. Tech. degrees in electrical engineering from the University of Oulu, Finland, in 2010 and 2016, respectively. He is currently working as a Postdoctoral Researcher in Circuits and Systems Research Unit in University of Oulu. His main research interest is the design of time interval measurement circuits.

Juha Kostamovaara (M’85, S’13) received the degrees of Dipl. Eng., Lic.Tech. and Dr.Tech in electrical engineering in 1980, 1982 and 1987, respectively, all from the University of Oulu, Finland. He was Acting Associate Professor of electronics in the department of electrical Engineering, University of Oulu, in 1987 −1993, and was nominated Associate Professor from the beginning of 1993. During 1994, he was an Alexander von Humboldt Scholar at the Technical University of Darmstadt, Germany. In 1995 he was invited to become full professor of electronics at the University of Oulu, where he is currently also the Head of the Circuits and Systems Research Unit. In 2007 he was nominated to the Academy professorship position by the Academy of Finland, which position he holds till 2017. His main interests are in the development of high-speed electronic circuits and systems and their applications in electronic and optoelectronic measurements.