Abstract
High sensitivity, broadband bandwidth, small size and scalability to a fine-pitch matrix of ultrasound (US) sensors are essential for high-resolution ultrasonography and photoacoustic tomography. In this work, we demonstrated a method to build micro-ring resonators (MRR) as US sensors on the Silicon-On-Insulator (SOI) platform. To improve the sensitivity, transverse magnetic (TM) mode is utilized to increase the mode interaction with the cladding as well as reduce the scattering loss caused by sidewall roughness. Besides, the SU-8 elastomer is introduced as cladding to enhance US response. The fabricated 10 μm-radius MRR with only one standard lithography process shows a high quality (Q) of 7.4 × 104 and a steep slope of 351 dB/nm. The US sensing bandwidth reaches 165 MHz at −6 dB with a high sensitivity of 14.5 mPa Hz−1/2. The high refractive index of the silicon waveguide contributes to an order of magnitude smaller sensing area than the polymer-based MRR. The proposed sensitive MRRs on the SOI platform makes it very promising for mass manufacturing integrated dense US arrays.
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription
Add to BibSonomy