CC BY
9*
ALT'23 The 30th International Conference on Advanced Laser Technologies
LM-I-8
Light-matter coupling in optical microcavities
M.C. Houghton1, K. Kurassova2, N.A. Toropov1,2, F. Vollmer1
1- University of Exeter, Exeter, UK, EX4 4QD 2- ITMO University, St. Petersburg, Russia, 197101 nikita. a. toropov@gmail.com
In this contribution, we discuss two aspects of light-matter interaction in optical microcavities: first - when microcavities are decorated with plasmonic nanostructures and used as biosensors; second - when microcavities are doped with fluorescent nanocrystals.
First aspect is related to biosensing with optical microcavities. Light circulating in such cavities forms whispering gallery modes (WGMs), which have extremely high quality-factors. High Q-factors make such cavities unsurpassed instruments for single-molecule sensing. In this work, we developed the idea of whispering gallery modes for single-molecule biosensing via decorating them with plasmonic nanoparticles. Despite high Q-factors, WGMs have comparatively big effective mode volume reducing sensitivity; in turn, plasmonic structures can concentrate energy of WGMs in a tiny area; this leads to a better sensitivity of WGM biosensors. Conventionally, WGMs used for biosensing can be excited with lasers and prism couplers, typical power levels are ~0.01-0.1 mW. In our latest work we extended this range, that showed us that molecules attached to such biosensors may strongly interact with plasmonic nanoparticles, showing strong nonlinear response of the sensors; in addition, we proposed to use a newly discovered phenomena for single-molecule absorption spectrometers.
In the second part of the talk, we will discuss light-matter interaction inside microcavities. Such cavities were made of polymers with added semiconductor nanocrystals via a microfluidics technique. Upon excitation of nanocrystals fluorescence in such cavities, there were observed its lifetime shorting by 100 of times in comparison with fluorescence of same nanocrystals in solutions. This is discussed in terms of the Purcell effect. The second part of this work was supported by the Russian Science Foundation (Project 22-72-10057).
