Optical Resonators for Photoacoustic Applications

PASSCODE: defense

Photoacoustic (PA) is one of the most powerful functional imaging techniques that provides ~ 10 mm resolution and mm-cm imaging depth. However, the necessary hardware for photoacoustic technology is still scarce and needs further development.

In this thesis, I first present the fabrication and characterization of a dome-shaped Fabry-Perot resonator on a fiber tip as an ultrasound sensor. The sensor is incorporated into a PA needle probe with ~ 1-mm diameter for photoacoustic spectral analysis. The Initial results suggest the potential application of prostate cancer staging.

I also develop photonic-integrated circuits with microring resonator arrays for photoacoustic tomography (PAT). I successfully fabricate polymer microring resonators with record-high Q-factors and an unprecedented number of sensing elements through nanoimprinting lithography. Initial imaging results are also presented.

To fabricate high Q-factor microrings beyond traditional nanoimprinting, I introduce Damascene soft nanoimprinting lithography (DsNIL). This process is residual layer-free, cost-effective, and high-throughput. It also allows for incorporating various polymers, thereby facilitating multiple functions.

CHAIR: Professor L. Jay Guo