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Spectroscopy of 1.55 υm PbS Quantum Dots on Si Photonic Crystal Cavities with a Fiber Taper Waveguide



Matthew T. Rakher, Ranojoy Bose, Chee Wei Wong, Kartik A. Srinivasan


We use an optical fiber taper waveguide to probe PbS quantum dots (QDs) dried on Si photonic crystal cavities near 1.55 υm. We demonstrate that a low density ({less than or equal to} 100υm-2) of QDs does not significantly degrade cavity quality factors as high as ≅3×104. We also show that the tapered fiber can be used to excite the QDs and collect the subsequent cavity-filtered photoluminescence, and present measurements of reversible photodarkening and QD saturation. This method represents an important step towards spectroscopy of single colloidal QDs in the telecommunications band.
Applied Physics Letters


photonic crystals, microcavities, quantum dots, spectroscopy
Created April 23, 2010, Updated February 19, 2017