Surface relief gratings induced by a nanosecond pulse in a liquid-crystalline azo-polymethacrylate Available to Purchase

Surface relief gratings have been generated in an azobenzene side chain liquid-crystal polymer using an intensity interference pattern from two coherent laser pulses (⁠$532nm$ and $4ns$⁠). We elucidate whether peaks or trenches correspond to the high intensity regions of the interference pattern. For low-energy pulses, peaks are generated in the irradiated areas while trenches appear for energies above a threshold (around $100mJ∕cm2$ per beam). This phenomenology, together with the lack of relief when polarization patterns are used, indicates that in this polymer surface relief has a thermal origin.