Overcoming thermo-optical dynamics in broadband nanophotonic sensing
Mingkang Wang, Diego J. Perez, Vladimir Aksyuk
Advances in integrated photonics open exciting opportunities for batch-fabricated optical nano- electro-mechanical sensors with ultra-high sensitivities and bandwidths enabled by cavity optomechanics. However, heat from the amplified optical intensity within a micrometer-scale mode volume prominently distorts the cavity resonances and strongly couples the optomechanical transfer function to thermal dynamics, complicating mechanical measurement. Here, we derive a frequency-dependent transfer function that accounts for thermo-optical dynamics and quantitatively describes the measured optomechanical response of an integrated photonic atomic- force-microscopy probe. The independent quantification of heating enables experimental separation of the optical absorption, radiative and coupling losses for ten microdisk cavity modes of three different radial orders. Similar absorptive loss rates are found for all modes despite order-of-magnitude differences in the total dissipation rate. The interplay between thermal dynamics and the varying radiation losses leads to a counterintuitive low-frequency transduction regime, where higher optomechanical gains are observed for lower quality factor modes.
, Perez, D.
and Aksyuk, V.
Overcoming thermo-optical dynamics in broadband nanophotonic sensing, Microsystems & Nanoengineering, [online], https://doi.org/10.1038/s41378-021-00281-y, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930033
(Accessed February 28, 2024)