Fabricating three-dimensional periodic micro-structure with planar defects via a single exposure

Abstract

In this paper, we introduce a method to incorporate a planar defect into the fcc-like photonic crystal structure by utilizing a negative photoresistor SU8. This method in which multi-coating and a single exposure are used simplifies the experiment much more than other methods. In the paper, we exhibit the SEM images for the intact and defective structures. Corresponding to each structure, the reflection spectrum in (1 1 1) direction fabricated shows obviously characteristic peaks and pits. For the intact structure, the spectrum contains two peaks whose wavelengths approach to 1.2 μm and 2.2 μm. These two peaks corresponds to two optical forbidden gaps. For the structure with planar defect, a pit which splits the optical forbidden gap is considered to be a defect mode exhibited on spectral curve. The structure parameters are extracted from the SEM image and used to simulate the reflectance spectra via FDTD program. The simulation results almost match the experiment data accurately.