Ming C. Wu (Advisor)

Traditional semiconductor light emitting diodes (LEDs) have low modulation speed because of long spontaneous emission lifetime. Spontaneous emission in semiconductors (and indeed most light emitters) is an inherently slow process owing to the size mismatch between the dipole length of the optical dipole oscillators responsible for light emission and the wavelength of the emitted light. More simply stated: semiconductors behave as a poor antenna for its own light emission. By coupling a semiconductor at the nanoscale to an external antenna, the spontaneous emission rate can be...

Semiconductor nanocavities are of interest for their potential as threshold-less lasers and high-speed modulated sources. When cavity volumes are shrunk below the size of a cubic wavelength, the rate of spontaneous emission can be enhanced. This so-called Purcell enhancement has lead to the misconception that the modulation speed of nanocavity lasers can be significantly enhanced beyond that of their classical (large volume) counterparts. Here, by performing a detailed analysis, we show that the modulation bandwidth can, indeed, be increased by the Purcell effect, but that this...

The goal of this project has been focused on developing a high port-count wavelength-selective switch using micromirror arrays.

Project end date: 08/31/05

Optical tweezers have been widely used to manipulate biological cells and particles since it was demonstrated by Ashkin in 1986. However, optical manipulation using direct optical force requires tight optical focusing and is only availabe in small area. Here, we proposed a novel mechanism which enables optical manipulation using optical power 5 orders of magnitude less than that of conventional optical tweezers. This mechanism is realied by inducing optically defined virtual electrodes on semiconductive thin films. This induced virtual electrodes create highly non-uniform electric...