REALIZATION OF SINGLE PHOTON TRANSPORT IN 2D PHOTONIC CRYSTALS

Abstract

Periodic dielectric structures offer a powerful means of controlling light at the wavelength scale. In this study, the propagation of single photon wave packets is investigated in a two dimensional hexagonal photonic crystal composed of gallium arsenide (GaAs) rods in air, operating in the near infrared region. By examining the photonic band structure as a function of the normalized rod radius r/a, a complete transverse magnetic (TM) photonic bandgap is identified near r/a = 0.274. A lattice constant of a = 422 nm is selected so that the operating wavelength of 810 nm lies well within this bandgap region. A W1 photonic crystal waveguide is formed by removing a single row of rods from the periodic lattice. The defect channel allows guided modes to propagate within the photonic bandgap region. Finite difference time domain (FDTD) simulations were used to examine the propagation of a Gaussian wave packet through the waveguide. The transmission coefficient was calculated to be approximately T≈0.983, corresponding to an insertion loss of about 0.073 dB. The simulated field profiles indicate that most of the electromagnetic energy remains confined inside the defect channel during propagation, while only small losses occur near the input and output sections. Overall, the study shows that a standard GaAs W1 photonic crystal waveguide can support efficient single photon transport in the near infrared region. This type of structure could be useful for low loss integrated quantum photonic devices.