Speaker
Description
Dielectric whispering gallery mode (WGM) resonators fabricated from single-crystal materials such as lithium niobate and lithium tantalate combine exceptionally high optical quality factors with strong second-order optical nonlinearities. This means that the resonators therefore provide strong field enhancement and extended interaction times, enabling efficient nonlinear frequency conversion at modest power levels. Recent work has further shown that, in the sub-terahertz regime, the modal structure and dispersion of WGMs can be tailored through resonator designs that are uniquely accessible via newer fabrication capabilities such as femtosecond laser ablation. The coexistence of low optical loss, large nonlinear susceptibility, and controllable dispersion makes these resonators a compelling platform for efficient nonlinear coupling between terahertz and optical frequencies, even across spectral bands separated by several orders of magnitude.
Building on recent demonstrations of multichannel upconversion of sub-terahertz signals in crystalline optical resonators, together with techniques that allow the direct visualization of sub-terahertz WGM fields, I will discuss how resonant nonlinear interactions can be engineered to enhance sensitivity while preserving access to multiple spectral channels. Such nonlinear optical transduction of millimeter-wave signals into the optical domain allows the use of mature, low-noise optical detection schemes and technologies unavailable in the lower-energy terahertz domain. Particular emphasis will be placed on the detection of molecular emission features relevant to the monitoring of stratospheric ozone and water vapour. These applications highlight the potential of WGM-based upconversion technology to bridge the terahertz and optical domains and enable next-generation flight-based sensing systems.
| I am the presenting author | No |
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| If you are not the presenting author, please give the presenting author's name: | Mallika Suresh |