A frequency-domain non-contact photoacoustic microscope based on an adaptive interferometer

作者：George Deepu; Lloyd Harriet; Silverman Ronald H; Chitnis Parag V^*

来源：Journal of Biophotonics, 2018, 11(6): e201700278.

DOI：10.1002/jbio.201700278

• interferometry
• microscopy
• photoacoustic imaging
• photorefractive crystal

A frequency-domain, non-contact approach to photoacoustic microscopy (PAM) that employs amplitude-modulated (0.1-1 MHz) laser for excitation (638-nm pump) in conjunction with a 2-wave mixing interferometer (532-nm probe) for non-contact detection of photoacoustic waves at the specimen surface is presented. A lock-in amplifier is employed to detect the photoacoustic signal. Illustrative images of tissue-mimicking phantoms, red-blood cells and retinal vasculature are presented. Single-frequency modulation of the pump beam directly provides an image that is equivalent to the 2-dimensional projection of the image volume. Targets located superficially produce phase modulations in the surface-reflected probe beam due to surface vibrations as well as direct intensity modulation in the backscattered probe light due to local changes in pressure and/or temperature. In comparison, the observed modulations in the probe beam due to targets located deeper in the specimen, for example, beyond the ballistic photon regime, predominantly consist of phase modulation.

• 出版日期2018-6