Multispectral photoacoustic coded excitation with low PRF high power laser diodes

Photoacoustic imaging is based on the generation of ultrasound using laser irradiation. Solid state laser systems are commonly employed for this purpose, but pulsed laser diodes can be an attractive alternative. Currently, a photoacoustic handheld probe is developed within the European Union project FULLPHASE and will include multiple wavelengths. In this probe, multiple wavelengths will be available simultaneously. This can be exploited for increasing the signal to noise ratio of acquired images by generating images containing all wavelengths (“fused” images) at the loss of spectral information. Here we show that applying a multispectral code instead of a simple fusion of the wavelengths, allows to generate both a high SNR fused image and separate wavelength images simultaneously. The concept is applied in experiments using two wavelengths.