Multiple higher-order bandgaps in infrared polymer photonic crystals

We present a new type of polymer photonic crystals which feature a multitude of higher-order bandgaps in the mid and near infrared spectral region. The crystals are void channel microstructures. Photonic band structure calculations are carried out using an iterative eigensolver program. Their results are consistent with the Fourier transform infrared spectra measured in transmission and reflection and allow for the determination of structural parameters such as the channel cross section and the effective refractive index of the polymer material after fabrication. With increasing ratio of the layer spacing to the in-plane channel spacing the number of higher-order bandgaps rises, and transitions from mere resonant angle Bragg reflections to bandgap total reflection are observed. We emphasize the enormous potential for applications of these highly correlated infrared polymer photonic crystals.