Person:

Loncar, Marko

We report a new approach for realizing a flexible photonic crystal (PC) cavity that enables wide-range tuning of its resonance frequency. Our PC cavity consists of a regular array of silicon nanowires embedded in a polydimethylsiloxane (PDMS) matrix and exhibits a cavity resonance in the telecommunication band that can be reversibly tuned over 60 nm via mechanical stretching—a record for two-dimensional (2D) PC structures. These mechanically reconfigurable devices could find potential applications in integrated photonics, sensing in biological systems, and smart materials.

This paper describes the fabrication of functional optical devices by sectioning quantum-dotin-nanowires systems with predefined lengths and orientations. This fabrication process requires only two steps: embedding the nanowires in epoxy, and using an ultramicrotome to section them across their axis (“nanoskiving”). This work demonstrates the combination of four capabilities: i) the control of the length of the nanowire sections at the nanometer scale; ii) the ability to process the nanowires after cutting using wet etching; iii) the possibility of modifying the geometry of the wire by varying the sectioning angle; and iv) the generation of as many as 120 consecutive slabs bearing nanowires which have uniform size and approximately reproducible lateral patterns, and which can subsequently be transferred to different substrates. The quantum dots inside the nanowires are functional and of a high optical quality after the sectioning process, and exhibit photoluminescent emission with wavelengths in the range of 650-710 nm.