Two dimensional sinusoidal Ag nanograting exhibits polarization‐independent surface‐enhanced Raman spectroscopy and its surface plasmon polariton and localized surface plasmon coupling with Au nanospheres colloids

A reproducible surface‐enhanced Raman scattering (SERS) substrate based on two dimensional (2D) sinusoidal Ag nanograting is presented. This SERS substrate with large area can be easily fabricated by maskless laser interference photolithography. The potential SERS polarization‐independent performance of 2D sinusoidal Ag nanograting is deduced by finite difference time domain and demonstrated by SERS detection experiments. A double‐enhanced Raman scattering (DERS) substrate by coupling 2D sinusoidal Ag nanograting with Au nanospheres colloids is created. With the optimal DERS substrate, SERS enhancement factor can be 10 orders of magnitude as possible. The DERS substrate was fabricated and an extra SERS effect was proved by experiments. This DERS substrate will be fabricated in a microfluidics‐based sensor in the next work and used for in situ, real‐time, continuous monitoring of trace water soluble gas‐phase or airborne agents, such as trace explosives in air. 2D sinusoidal Ag nanograting provides an interesting and effective method to achieve the goal of SERS polarization‐independent, future practical SERS detection application maybe have no need of a certain optimal polarization direction of excitation light outside the laboratory setting. If Au nanospheres colloids can keep flowing above the surface of 2D sinusoidal Ag nanograting, this DERS substrate can overcome memory effect and the noncontinuous work of the traditional SERS substrate.