Dual-Wavelength Continuous Wave Photoacoustic Doppler Flow Measurement

Abstract Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting power spectra. Extending this technique to dual wavelengths can gain spectral information sample extra speed information. An experimental system with two diodes respectively operated at 405 nm and 660 is built black red dyed polystyrene beads performed. The measured spectra vividly reflect speed, direction, as well bead color. Since it straightforward further apply same principle multiple wavelengths, we expect type spectroscopic photoacoustic will be developed in near future which very useful for studying metabolism slowly moving blood cell inside microvessels.