PDMS-based subwavelength structures for broadband and wide-angle anti-reflection

Subwavelength structures were reported to have excellent anti-reflection (AR) performance. However, it is difficult to achieve effective AR in broadband and wide-angle. In this work, we report the new subwavelength structures fabricated by polydimethylsiloxane (PDMS) for broadband and wide-angle AR. Two new subwavelength structures, alternating structure and stacking structure, are designed. The admittance recursive method is used to calculate the reflectance of subwavelength structures in the range of incident wavelengths from 200 nm to 2500 nm and incident angles from 0 degrees to 80 degrees. It is found that the combination of the 300 nm stacking structure on the front surface and the 500 nm alternating structure on the back surface has the better AR performance. In the wide spectrum and wide incident angle, the maximum reflectance is reduced to 6.8% and 12.0%. Compared to bare glass, the average transmittance was increased by 6.6% and 12.4%, respectively.