Abstrakt: |
We find that the phase shifts of reflected light within band gap of two-dimensional photonic crystal (PC) are as follows: with frequency altering from the lower edge to the upper edge of first stop band, the reflection phase shift varies from -π to 0 for the PC's unit cell with the high-index material near the center, while it varies from 0 to π for that with low-index material near the center. For the higher-order stop band, there exists a certain value of filling fraction, which makes the phase shifts in higher-order stop bands almost the same as that in the first stop band. When the filling fraction is far from that value, the phase shifts are significantly different. The further study on the Bloch modes demonstrates that their distribution of electric field and magnetic field determines the phase shifts. Moreover, we have found that, in the overlap area of transverse magnetic and transverse electric stop band, the phase difference between two polarizations of reflected light can remain invariant in a broad frequency region. Based on this property, the broadband and angle-insensitive phase retarders are designed. These interesting phase characteristics will bring about many potential applications. [ABSTRACT FROM AUTHOR] |