Observation of high contrast ratio asymmetric transmission for linearly and circularly polarized waves

Asymmetric transmission of light has important applications in integrated photonic systems for communications and information processing. Various Lorentz-reciprocal devices have been explored to achieve asymmetric transmission. However, the contrast ratio is limited. Here we show that the asymmetric transmission of linearly polarized and circularly polarized waves can both be achieved by combining polarization conversion and selective transmission. What is perhaps most important here is that the proposed asymmetric transmission devices for operation at wavelength 633 nm experimentally display asymmetric transmission with contrast ratio exceeding 37 dB and 34 dB for linearly polarized wave and circularly polarized wave, respectively. The high contrast ratios are much higher than previous results in published literature. The proposed reciprocal approach holds promising for utilization in integrated photonic systems. (paper)