26 August 2015 Photothermal microresonator absorption microscopy with backscatter detection
Author Affiliations +
The extreme temperature sensitivity of whispering-gallery-mode (WGM) microresonators holds great promise as a detection strategy for single-particle photothermal microscopy and spectroscopy. The detection limit is currently partially constrained by frequency noise from the laser used to probe the cavity resonance wavelength. We present a measurement technique capable of simultaneously detecting backscattered and transmitted light from a wavelengthlocked optical microresonator, with laser intensity noise and frequency noise partitioned into the two independent detection channels. Photothermal mapping of single absorbing nano-objects demonstrates that both methods are capable of high signal/noise, exceeding 30,000:1 in the backscattering channel for a photothermally-induced microresonator resonance shift of 93 fm.
Conference Presentation
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Kevin D. Heylman, Kevin D. Heylman, Erik H. Horak, Erik H. Horak, Kassandra A. Knapper, Kassandra A. Knapper, Randall H. Goldsmith, Randall H. Goldsmith, } "Photothermal microresonator absorption microscopy with backscatter detection", Proc. SPIE 9554, Nanoimaging and Nanospectroscopy III, 95540U (26 August 2015); doi: 10.1117/12.2187240; https://doi.org/10.1117/12.2187240

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