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CUDOS researchers in collaboration with Stanford University demonstrate local tuning of GaAs-based photonic crystal cavities using chalcogenide glass -- an important advance towards quantum dot based single photon sources.
This collaboration between Prof. Luther-Davies at ANU, Prof. Eggleton at Usyd and Prof. Jelena Vuckovic at Stanford University exploited the photosensitivity of a thin film of chalcogenide to tune the resonance of GaAs-based photonic crystal cavities. See the publication below or contact Prof Eggleton for more details.
Andrei Faraon, Dirk Englund, Douglas Bulla, Barry Luther-Davies, Benjamin J. Eggleton, Nick Stoltz, Pierre Petroff, and Jelena Vuckovic, "Local tuning of photonic crystal cavities using chalcogenide glasses" Appl. Phys. Lett. 92, 043123 (2008) Summary: We demonstrate a method to locally change the refractive index in planar optical devices by photodarkening of a thin chalcogenide glass layer deposited on top of the device. The method is used to tune the resonance of GaAs-based photonic crystal cavities by up to 3 nm at 940 nm. The method has broad applications for postproduction tuning of photonic devices. 
Fig. 3. (a) Spectra showing cavity and QD shifting, as a function of exposure time. The QD lines first shift rapidly, presumably through changing material strain induced by the chalcogenide layer. Soon after, the QD lines become stationary, while the cavity continues to redshift. This data set was taken on a sample with 50 nm of As2S3. (b) Individual scans of QD/cavity tuning show that after strain relaxation, the cavity can be shifted independently of the QDs. Scans 4–7 were taken for t>2 min when the pump power was temporarily increased to speed up the chalcogenide exposure. |
