A sensing device that produces a Raman signal includes micro-rods or nano-rods arranged on a substrate in a two-dimensional (2D) array, each of the rods having a length in a single row being substantially the same, with the rod length of each row being different from the rod length of each other row. Each row of rods has a respective resonant vibration frequency that varies from row to row. A source of vibration energy, operatively connected to the substrate, excites vibration in each of the rods such that a responding row resonates when an exciting frequency approaches the resonant vibration frequency of the responding row. A method includes exposing the 2D array to a light source and analyzing Raman scattering at each rod of the 2D array to render a Raman map.