Ultra-fast remote photoacoustic imaging with a non-scanning speckle-based setup

Abstract

A method for fast non-scanning remote photoacoustic imaging is presented and experimentally demonstrated. The approach is based on speckle contrast measurement, proceeding the previously developed method for speckle contrast based photoacoustic detection. This previously developed method is now presented without the need for raster scanning of the sample, an advantage rarely found in optical photoacoustic detection, and offers 50 times faster as well as a simpler remote photoacoustic scheme in respect to interferometric available solutions.

Non-contact detection of ultrasound with light – Review of recent progress

“…Non-scanning detection of surface waves in the MHz frequency range was demonstrated for a metal plate in Ref [96] with the full field photorefractive interferometry. Instead of using the conventional focused probe beam scanning over the sample surface, the medium was probed with a wide (16 mm in diameter) beam.…”

“…To address the problem of the sample surface quality in full field imaging, a simple non-scanning speckle-based approach was proposed [96] . Indeed, surface vibration caused by US signals can be computed by calculating the contrast of the reflected speckle pattern [97] generated by a probe laser beam.…”

“…In Ref. [96] , the diffused beam was projected to a surface of a glass cuvette with a light-absorbing object inside which was irradiated with nanosecond pump laser pulses (photoacoustic geometry). A temporal resolution of 1 μs was achieved which allowed to obtain an image resolution of about 1 mm.…”

All Optical Speckle Contrast-Based Vibration Sensor for Photoacoustic Signal Detection

“…Since imaging devices often present limited frame rate, not sufficient to explore the MHz bandwidth characterizing PA signals, Speckle contrast-based methods were suggested as an appropriate solution [11][12][13].…”

“…This may be a drawback of contrast-based methods. Benyamin presented a scheme containing temporal scanning in order to address this issue, and applied the idea to perform back projectionbased image reconstruction, which uses temporal information of the vibration signal [12]. Even though the method used by Benyamin presents somewhat different signals, with limited temporal resolution compared to piezoelectric transducers, it was demonstrated how those signals do employ the required information in order to perform back-projection imaging.…”