Fluorescence spectroscopy and signalling from optically-tweezed aerosol droplets

Spectroscopic signatures from fluorescing optically-tweezed aqueous droplets in air and polymer beads in solution are presented and compared. Rapid fluorescence signalling is reported for the aerosol droplets with a time resolution of 34 ms, achieved by dosing a trapped droplet with a fluorescent dye via coalescence with a flow of dye-doped aerosol. The quality factors of cavity-enhanced resonances present in the emission spectra are compared with those reported in a range of other studies. Rapid aerosol droplet heating is observed following coalescence for the case of high dye-loading.