Nonlinear photoacoustic microscopy via a loss modulation technique: from detection to imaging
Abstract
In order to achieve high-resolution deep-tissue imaging, multi-photon fluorescence microscopy and photoacoustic tomography had been proposed in the past two decades. However, combining the advantages of these two imaging systems to achieve optical-spatial resolution with an ultrasonic-penetration depth is still a field with challenges. In this paper, we investigate the detection of the two-photon photoacoustic ultrasound, and first demonstrate background-free two-photon photoacoustic imaging in a phantom sample. To generate the background-free two-photon photoacoustic signals, we used a high-repetition rate femtosecond laser to induce narrowband excitation. Combining a loss modulation technique, we successfully created a beating on the light intensity, which not only provides pure sinusoidal modulation, but also ensures the spectrum sensitivity and frequency selectivity. By using the lock-in detection, the power dependency experiment validates our methodology to frequency-select the source of the nonlinearity. This ensures our capability of measuring the background-free two-photon photoacoustic waves by detecting the 2nd order beating signal directly. Furthermore, by mixing the nanoparticles and fluorescence dyes as contrast agents, the two-photon photoacoustic signal was found to be enhanced and detected. In the end, we demonstrate subsurface two-photon photoacoustic bio-imaging based on the optical scanning mechanism inside phantom samples.
Additional Information
© 2014 Optical Society of America. Received 16 Oct 2013; revised 9 Dec 2013; accepted 9 Dec 2013; published 3 Jan 2014. This work is funded by National Science Council, Taiwan (NSC 100-2120-M-002-009) and National Health Research Institute (NHRI-EX101-9936EI). We appreciate the support of Prof. Pai-Chi Li, whose group inspired us to design a better ultrasonic cavity and testing system. We thank Dr. Huan-Cheng Chang, whose group provided us with the sample of pure nano-diamonds. We acknowledge the valuable technical supports from Dr. Chien-Cheng Chen and Dr. Pierre-Adrien Mante. We appreciate the useful advices and generous discussions from Dr. Yu-Ru Huang and Dr. Ming-Rung Tsai. All the works were performed in National Taiwan University. This work is based on a previous SPIE conference proceeding [23]. The content is fully expanded, developed, reorganized and corrected.Attached Files
Published - oe-22-1-525.pdf
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Additional details
- Eprint ID
- 44236
- Resolver ID
- CaltechAUTHORS:20140311-085849127
- NSC 100-2120-M-002-009
- National Science Council (Taipei)
- NHRI-EX101-9936EI
- National Health Research Institute
- Created
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2014-03-12Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field