All-optical optoacoustic microscopy system based on probe beam deflection technique

Saher M. Maswadi, Dmitri Tsyboulskic, Caleb C. Roth, Randolph D. Glickman, Hope T. Beier, Alexander A. Oraevsky, Bennett L. Ibey

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

Abstract

It is difficult to achieve sub-micron resolution in backward mode OA microscopy using conventional piezoelectric detectors, because of wavefront distortions caused by components placed in the optical path, between the sample and the objective lens, that are required to separate the acoustic wave from the optical beam. As an alternate approach, an optoacoustic microscope (OAM) was constructed using the probe beam deflection technique (PBDT) to detect laserinduced acoustic signals. The all-optical OAM detects laser-generated pressure waves using a probe beam passing through a coupling medium, such as water, filling the space between the microscope objective lens and sample. The acoustic waves generated in the sample propagate through the coupling medium, causing transient changes in the refractive index that deflect the probe beam. These deflections are measured with a high-speed, balanced photodiode position detector. The deflection amplitude is directly proportional to the magnitude of the acoustic pressure wave, and provides the data required for image reconstruction. The sensitivity of the PBDT detector expressed as noise equivalent pressure was 12 Pa, comparable to that of existing high-performance ultrasound detectors. Because of the unimpeded working distance, a high numerical aperture objective lens, i.e. NA = 1, was employed in the OAM to achieve near diffraction-limited lateral resolution of 0.5 μm at 532nm. The all-optical OAM provides several benefits over current piezoelectric detector-based systems, such as increased lateral and axial resolution, higher sensitivity, robustness, and potentially more compatibility with multimodal instruments.

Original languageEnglish (US)
Title of host publicationPhotons Plus Ultrasound: Imaging and Sensing 2016
PublisherSPIE
Volume9708
ISBN (Electronic)9781628419429
DOIs
StatePublished - 2016
EventPhotons Plus Ultrasound: Imaging and Sensing 2016 - San Francisco, United States
Duration: Feb 14 2016Feb 17 2016

Other

OtherPhotons Plus Ultrasound: Imaging and Sensing 2016
CountryUnited States
CitySan Francisco
Period2/14/162/17/16

Keywords

  • All-optical optoacoustic detection
  • backward mode
  • non-contact sensor
  • optical resolution optoacoustic imaging
  • optoacoustic microscopy
  • probe beam deflection technique

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

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