Ultra-high sensitive all-optical photoacoustic transducers

We present all-optical ultrasound transducers that is suitable for photoacoustic applications. We leverage the benefits of CMOS compatible on-chip photonic sensor that is realized by patterning the integrated photonic circuits overlaid on membrane cavity responding to incoming acoustic signals. The sensor is based on SiN based photonic ring resonator on top of 3-micron thick SiO2 membrane. Latched on the optical read out circuit, the sensor hardware architecture promises ultra-high sensitivity with the ability to detect as low as <1 mPa/sqrt(Hz) noise equivalent pressure. The hardware architecture can be further improved to leverage the benefits of existing photonic based signal conditioning schemes and adopt them to multiplex the ultrasound reception from multiple sensor elements.