SERS polarization-independent performance of two-dimensional sinusoidal silver grating

This letter demonstrates a possibility to overcome the polarization-dependent problem in surface enhanced Raman scattering (SERS) performance by two-dimensional (2D) sinusoidal silver grating. A reproducible SERS substrate with a large area can be easily fabricated by maskless laser interference photolithography. The polarization-independent SERS performance and SERS enhancement factor (EF) of this substrate are deduced by finite difference time domain and demonstrated by R6G SERS detection experiments. SERS performance of 2D sinusoidal grating is polarization-independent over the whole 360 degrees and EF can be 5 orders of magnitude as possible. Moreover, this long-range SERS substrate can realize label-free SERS detection of 2,4,6-Trinitrotoluene (TNT).