TeraHz tuning of whispering gallery modes in a PDMS, stand-alone, stretchable microsphere

TL;DR

This paper demonstrates a stretchable PDMS microsphere resonator capable of tuning whispering gallery modes over a THz range through mechanical stretching, with high sensitivity to applied force.

Contribution

It introduces a novel, stand-alone, stretchable PDMS microsphere resonator with tunable whispering gallery modes via simple mechanical stretching.

Findings

Achieved over 1 THz tuning range of whispering gallery modes.

Demonstrated higher sensitivity (0.13 nm/μN) in the stretched state.

Resonator can be tuned by tens of microns through mechanical stretching.

Abstract

We report on tuning the optical whispering gallery modes in a poly dimethyl siloxane-based (PDMS) microsphere resonator by more than a THz. The PDMS microsphere system consists of a solid spherical resonator directly formed with double stems on either side. The stems act like tie-rods for simple mechanical stretching of the microresonator over tens of microns, resulting in tuning of the whispering gallery modes by one free spectral range. Further investigations demonstrate that the whispering gallery mode shift has a higher sensitivity (0.13 nm/{\mu}N) to an applied force when the resonator is in its maximally stretched state compared to its relaxed state.