Raman Threshold Lowering in Globular Photonic Structures Filled with Liquids

Abstract

Stimulated Raman Scattering (SRS) in globular photonic crystals and glasses (at di˙erent diameters of the globules from 250 nm up to 2.3 mm) with embedded molecular liquids is studied under excitation with nanosecond or picosecond laser pulses. Substantial decrease of SRS threshold has been observed. Such a phenomenon is explained as the result of laser radiation field increase in globular photonic structures due to photonic density of states enhancement near the edges of photonic stop bands of photonic crystals, and due to Mie resonances or whispering gallery modes. Raman threshold lowering in globular photonic crystals and glasses opens the way to creating the new e˚cient laser sources based on composite globular photonic structures