I am looking for the cheaper substrate for Raman measurement of bacteria, without compromising much on the quality of spectra, also does anybody have experience with metal coated slide for acquisition of raman spectra from bacteria?
It depends to some extent on what wavelength you are using - here is an overview
“Optimal choice of sample substrate and laser wavelength for Raman spectroscopic analysis of biological specimen”, Laura T. Kerr, Hugh J. Byrne, Bryan M. Hennelly, Analytical Methods, 7, 5041-5952 (2015)