Photonics and Nanostructures Laboratory

Our group is interested in developing new optical materials and devices by controlling composition on length scales from 5 nm -500 nm. Electron-beam, atomic-force-microscopy (AFM), and optical lithographies are used in conjunction with a variety of etching and deposition technologies to produce 3D-textured structures in which the electronic and photonic eigen states can be “designed” by judicious choice of patterns, length scales and material combinations. The motivation is to offer optical device engineers a more diverse range of material options when developing next and next-next generation technologies.

Ours was one of the first groups to develop planar photonic crystals in thin semiconductor membranes. Much of the early work was in III-V membranes (GaAs, InP), which were used to demonstrate their utility for engineering classical, second order nonlinear optical response at low optical power levels. Work in silicon membranes revealed strong third order nonlinear responses. These proof of principle samples and experiments were largely based on isolated photonic crystals and photonic crystal microcavities fabricated locally using our cleanroom processing facility that includes optical lithography, e-beam and sputter-deposition systems, an ECR remote plasma etcher, a scanning electron microscope, and a rapid thermal annealer.

Current work focusses on full optical circuits, primarily in silicon, that efficiently couple radiation into and out of silicon-on-insulator (SOI) membranes in which various microcavities are coupled via single mode waveguides. These samples are fabricated at larger scale nanofabrication facilities around the world.

We have a wide range of optical instrumentation for linear and nonlinear, continuous wave and time-resolved (with 100 fs resolution), spectroscopic investigations of our samples. A strong emphasis is placed on developing quantitative, but heuristic numerical models to help design and understand the properties of interest.