Quickly Alternating Green and Red Laser Source for Real-time Multispectral Photoacoustic Microscopy

Sang Min Park, Do Yeon Kim, Soon Woo Cho, Beop Min Kim, Tae Geol Lee, Chang Seok Kim, Sang Won Lee

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Multispectral photoacoustic microscopy uses a wavelength-dependent absorption difference as a contrast mechanism to image the target molecule. In this paper, we present a novel multispectral pulsed fiber laser source, which selectively alternates the excitation wavelengths between green and red colors based on the stimulated Raman scattering (SRS) effect for imaging. This laser has a high pulse repetition rate (PRR) of 300 kHz and high pulse energy of more than 200 nJ meeting the real-time requirements of optical-resolution photoacoustic microscopy imaging. By switching the polarization state of the pump light and optical paths of the pump light, the operating wavelengths of the light source can be selectively alternated at the same fast PRR for any two SRS peak wavelengths between 545 and 655 nm. At 545 nm excitation wavelength, molecular photoacoustic signals from both blood vessels and gold nanorods were obtained simultaneously. However, at 655 nm, the photoacoustic signals of gold nanorods were dominant because the absorption of light by the blood vessels decreased drastically in the spectral region over 600 nm. Thus the multispectral photoacoustic system designed using the novel laser source implemented here could simultaneously monitor the time-dependent fast movement of two molecules independently, having different wavelength-dependent absorption properties at a high repetition rate of 0.49 frames per second (fps).

Original languageEnglish
Article number100204
JournalPhotoacoustics
Volume20
DOIs
Publication statusPublished - 2020 Dec

Keywords

  • Fiber laser
  • Gold nanoparticle
  • Molecular imaging
  • Photoacoustic microscopy
  • Stimulated Raman scattering

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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