Micro-Raman scattering imaging of Langmuir-Blodgett surface relief gratings

Surface relief gratings (SRGs) recorded on Langmuir-Blodgett (LB) films of an azobenzene homopolymer were visualized using micro-Raman imaging. Raman scattering (RS) was achieved using the 780 nm laser line while pre-resonanc e Raman scattering (pre-RRS) and resonance Raman scattering were achieved u sing the 633 and 514.5 nm laser lines, respectively, Pre-surface-enhanced r esonance Raman scattering (pre-SERRS) and surface-enhanced resonance Raman scattering (SERRS) were collected for the LB films covered with a 6 nm thic k silver island film. The SRG could be chemically identified by the spatial variation in the Raman signal scattered by the film due to a concentration gradient. The pre-SERRS provided signals of the same intensity along and a cross the grooves, indicating that the molecular architecture at the SRG su rface is the same at the peaks as in the valleys.