Measurement of band structures of photonic bandgap materials by picosecond optoelectronic techniques

Abstract

In this talk, we discuss the application of ultrafast optoelectronics to the measurement of band structure in two-dimensional photonic crystals. For the first time, the imaginary wave-vector dispersion in the bandgap region is measured using the coherent microwave transient spectroscopy (COMITS) technique. Also, by constructing the photonic analog of a semiconductor quantum well, we observe quantized states in the photonic band gap. Photonic analogs of semiconductor quantum wells are constructed by sandwiching a region of empty lattice between two sets of photonic crystal (barrier). To probe photonic quantized states, the barrier thickness is chose to be sufficiently thin to allow finite transmission of EM waves through the band gap region of the photonic crystal. In contrast to the electronic energy level in semiconductor quantum wells, the photonic quantized state shifts to higher frequencies as the well width is increased. These results will also be discussed.