High-frequency ultrasound sensors using polymer microring resonators

Area of Science:

• Photonics and acoustics
• Materials science
• Optical sensing

Background:

• Optical microring resonators are sensitive to changes in their environment.
• Ultrasound detection typically relies on piezoelectric or capacitive methods.
• Developing novel high-frequency ultrasound detectors is crucial for various applications.

Purpose of the Study:

• To demonstrate polymer microring resonators as effective high-frequency ultrasound detectors.
• To investigate the mechanism of ultrasound detection using optical strain and elasto-optic effects.
• To discuss design considerations for microring resonator ultrasound detector arrays.

Main Methods:

• Fabrication of polymer microring resonators with coupled bus waveguides.
• Experimental setup to irradiate resonators with broadband ultrasound pulses (50 MHz transducer).
• Analysis of optical resonance shifts due to acoustic-induced strain and refractive index changes.

Main Results:

• Successful detection of broadband ultrasound pulses using polymer microring resonators.
• Demonstrated enhancement of optical response to acoustic strain via resonance properties.
• Measured frequency response indicating potential for high-frequency ultrasound detection.

Conclusions:

• Polymer microring resonators are viable for high-frequency ultrasound detection.
• The elasto-optic effect and waveguide deformation are key to the detection mechanism.
• Further development can lead to advanced ultrasound detector arrays.