ABSTRACT
Multiple-filter stopbands, with the potential to be nonuniformly spaced in frequency, are realized in a single integrated Bragg grating device on silicon. By utilizing a superposition of sidewall relief grating functions, N individual filter responses can be fabricated with a device length N× shorter than the equivalent serial set of gratings. Arbitrary combinations of eight-basis filter responses were demonstrated as selected by an eight-bit pseudorandom number generator, showing the flexibility of the complex Bragg grating device design.
ABSTRACT
Experimentally measured optical properties of photonic crystal LEDs are reported here. Photonic crystal and photonic quasi-crystal structures were fabricated on GaN epilayer LED wafer material using both direct-write electron beam lithography and nanoimprint lithography. Some of these structures were processed to make finished LEDs. Both electroluminescence and photoluminescence measurements were performed on these structures. Devices were characterized for their current-voltage characteristics, emission spectra, far-field emission pattern, and angular emission pattern. These results are useful for fabricating photonic crystal LEDs and assessing their operational properties.
