Polymeric photonic molecule super-mode lasers on silicon

Scientists in Germany have constructed miniature single-mode lasers comprised of two coupled polymer microdisk cavities on silicon. Tobias Grossmann and co-workers from the Karlsruhe Institute of Technology say that their ‘photonic molecule’ lasers may prove useful for experiments in quantum optics or optofluidic sensing. The lasers are made by spin-coating a 1.2-μm-thick layer of the polymer PMMA onto a silicon substrate and using the laser dye Pyrromethene 597 as the gain material. Electron-beam lithography can then be used to create a pair of closely spaced microdisks with radii of 20–25 μm, subsequent deposition of PPX can be applied to accurately reduce the coupling gaps to 0–200 nm. When optically pumped with short green laser pulses, the photonic molecule lasers exhibited single-mode lasing in the yellow/orange spectral range.