University of Oulu

Talala, T., Kaikkonen, V. A., Virta, E., Mäkynen, A. J., & Nissinen, I. (2023). Multipoint Raman Spectrometer Based on a Time-Resolved CMOS SPAD Sensor. In IEEE Photonics Technology Letters (Vol. 35, Issue 11, pp. 629–632). Institute of Electrical and Electronics Engineers (IEEE).

Multipoint Raman spectrometer based on a time-resolved CMOS SPAD sensor

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Author: Talala, Tuomo1; Kaikkonen, Ville A.2; Virta, Eetu1;
Organizations: 1Circuits and Systems Research Unit, University of Oulu, 90014 Oulu, Finland
2ptoelectronics and Measurement Techniques Research Unit, University of Oulu, 90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2023
Publish Date: 2023-09-29


The potential of in-line Raman spectrometers for process monitoring applications has been shown for many industrial processes, but in most cases, only one measurement point has been monitored by one spectrometer. In this letter, we describe and demonstrate a novel, time-resolved method for measuring Raman spectra and fluorescence lifetimes from multiple points using a single excitation source and a single spectrometer. This technique is based on a combination of a time-resolved CMOS SPAD (single-photon avalanche diode) line sensor and a fitting optical light guiding system. The line sensor is designed to make multiple individual measurements at intervals of tens of nanoseconds and the optical light guiding system, in turn, produces matching temporal differences for optical signals from different measurement points. Thereby, signals from different points are distinguished in the time domain. A combined Raman and fluorescence lifetime monitoring of two measurement points was demonstrated with an oil-ethanol emulsion sample.

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Series: IEEE photonics technology letters
ISSN: 1041-1135
ISSN-E: 1941-0174
ISSN-L: 1041-1135
Volume: 35
Issue: 11
Pages: 629 - 632
DOI: 10.1109/LPT.2023.3268333
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was supported by the Academy of Finland under Contract 314404, Contract 314405, and Contract 323719.
Academy of Finland Grant Number: 314404
Detailed Information: 314404 (Academy of Finland Funding decision)
314405 (Academy of Finland Funding decision)
323719 (Academy of Finland Funding decision)
Copyright information: © 2023 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see