Laser power modulation with wavelength stabilization in multiple exposure laser speckle contrast analysis

Tomi Smausz, Dániel Zölei, Béla Hopp

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Switching mode intensity modulation had been applied to the illumination of a LASCA system using multiple exposure times to substitute a variable neutral filter, which allows the variation of the exposure time from frame to frame. In most cases the direct current (DC) control of the laser intensity can lead to changes in the wavelength of regular laser diodes. The use of pulsed mode operation can avoid the mode hopping of the laser light while it offers the tuning of the average intensity in a wide range. While operating the camera at a constant integration time, the length of the exposition was varied from 2 ms to 100 ms by changing the duration of the illuminating laser pulse train. The pulse train was built up of 10 pulses, each having the length of 40 μs with variable separation time. The mode stability of the light source was monitored with a spectrometer, meanwhile speckle images of a static scattering surface were recorded as well. This paper demonstrates the usefulness of this technique in a multi-exposure LASCA system for monitoring the changes in the skin perfusion.

Original languageEnglish
Title of host publicationSpeckle 2012
Subtitle of host publicationV International Conference on Speckle Metrology
DOIs
Publication statusPublished - Dec 1 2012
Event5th International Conference on Speckle Metrology, Speckle 2012 - Vigo, Spain
Duration: Sep 10 2012Sep 12 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8413
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

Other5th International Conference on Speckle Metrology, Speckle 2012
CountrySpain
CityVigo
Period9/10/129/12/12

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Keywords

  • full-field LASCA
  • modulated laser illumination
  • multiple exposure times

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Smausz, T., Zölei, D., & Hopp, B. (2012). Laser power modulation with wavelength stabilization in multiple exposure laser speckle contrast analysis. In Speckle 2012: V International Conference on Speckle Metrology [84131J] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 8413). https://doi.org/10.1117/12.978230