title: Polymer Microring Resonators for High-Frequency Ultrasound Detection and Imaging.
abstract: Polymer microring resonators fabricated by nanoimprinting are presented as a means of ultrasound detection. Acoustic waves impinging on a ring-shaped optical resonator cause strain in the ring dimensions, modulating optical output. Basic acoustic and optical characteristics of the microring sensor are presented. Measurements at several frequencies show a high sensitivity and low noise-equivalent pressure. The angular response is determined by sensing the optoacoustic excitation of a 49 μm polyester microsphere and shows wide-angle sensitivity. A 1-D array consisting of 4 microrings is demonstrated using wavelength multiplexing for addressing each element. The high sensitivity, bandwidth, and angular response make it a potentially useful sensor platform for many applications including high-frequency ultrasonic and photoacoustic imaging.
authors.affiliation: A. Maxwell, T. Ling, J.-S. Kim and L. J. Guo are with the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor, MI 48109 USA (Email:  guo@umich.edu ).
authors.forename: Adam
authors.initials: A
authors.lastname: Maxwell
authors.forename: Sheng-Wen
authors.initials: SW
authors.lastname: Huang
authors.forename: Tao
authors.initials: T
authors.lastname: Ling
authors.forename: Jin-Sung
authors.initials: JS
authors.lastname: Kim
authors.forename: Shai
authors.initials: S
authors.lastname: Ashkenazi
authors.forename: L Jay
authors.initials: LJ
authors.lastname: Guo