Broadband two-dimensional photonic crystal wave plate

It is demonstrated in this work that the phase shift of reflected wave as a function of frequency changes smoothly within the stop band of two-dimensional photonic crystal, while it changes sharply within the passband. In the stop band, the difference between the phase shift of TE and that of TM reflected wave could remain constant in a rather wide frequency region. By using the difference of phase shift, the authors obtain a kind of half-wave plate that can be used in broad spectral bandwidth. Such photonic crystal wave plates have predominance in optical and optoelectronic integration.