Fiber-laser-based photoacoustic microscopy and melanoma cell detection
For broad applications in biomedical research involving functional dynamics and clinical studies, a photoacoustic microscopy system should be compact, stable, and fast. In this work, we use a fiber laser as the photoacoustic irradiation source to meet these goals. The laser system measures 45×56×13 cm^3. The stability of the laser is attributed to the intrinsic optical fiber-based light amplification and output coupling. Its 50-kHz pulse repetition rate enables fast scanning or extensive signal averaging. At the laser wavelength of 1064 nm, the photoacoustic microscope still has enough sensitivity to image small blood vessels while providing high optical absorption contrast between melanin and hemoglobin. Label-free melanoma cells in flowing bovine blood are imaged in vitro, yielding measurements of both cell size and flow speed.
Additional Information© 2011 SPIE. Paper 10158SSR received Mar. 24, 2010; revised manuscript received Sep. 23, 2010; accepted for publication Oct. 21, 2010; published online Jan. 11, 2011. This work was supported in part by National Institutes of Health Grants Nos. R01 EB000712, R01 EB008085, R01 CA113453901, U54 CA136398, 5P60 DK02057933, and R43 RR025928. Wang has a financial interest in Microphotoacoustics, Incorporated, and Endra, Incorporated, which, however, did not support this work. The authors are grateful to Christopher Favazza for beneficial discussions. They also thank Jim Ballard for careful proofreading.
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