Photoacoustic Imaging

I am working toward innovation in laser technology tailored for photoacoustic imaging (PAI)—an in-vivo imaging technique based on the photoacoustic effect. This modality uniquely combines the rich optical absorption contrast of light with the deep penetration capability of ultrasound, enabling high-resolution, functional imaging within biological tissue. Acoustic waves generated by endogenous chromophores upon pulsed light absorption are captured using an ultrasonic transducer to form images.

Our group identified a critical gap in current PAI systems: optical parametric oscillators (OPOs), though tunable and high in pulse energy, are bulky and costly. In contrast, supercontinuum sources are compact but often lack the required pulse energy for quality imaging. To address this, we developed a new class of Raman fiber lasers that are wavelength-tunable, deliver micro-joule pulse energies, operate at high repetition rates, and are compact and scalable—making them ideal for multispectral photoacoustic imaging.

This laser platform enabled photoacoustic spectroscopy of commercial-grade cholesterol, a result previously achievable only with OPO systems. Our compact, accessible Raman fiber laser system thus represents a promising alternative for broader deployment of photoacoustic imaging technology.