Spectral and polarization characteristics of a deformed droplet laser

A fluorescent microdroplet was created in an elastomer by using a glycerol, polyethylene-glycol, or polysorbate solution of rhodamine 6G. Droplets exhibited a whispering gallery mode emission at a specific spectral band (yellow-green to orange), which shifted to a longer wavelength range (redshift) as the droplet diameter increased. The TE mode emission was stronger than the TM mode emission. As the elastomer was pressed in one direction, the droplet expanded in the perpendicular directions. Consequently, the resonant emission disappeared in the pressure direction, while the emission in the perpendicular direction exhibited the redshift of the resonance peaks.