Patent ID: 7016034

Claim:
A method for identifying particles, said method comprising: depositing at least one particle from a gaseous or liquid media onto a supporting substrate wherein said supporting substrate comprises a filter membrane of polymer materials of a defined pore width, and wherein said filter membrane includes a surface coated with a metal layer that has no spectral features in a wavelength range selected for spectroscopic identification and that absorbs no or only little of the laser energy which is radiated in at a selected excitation wavelength, the surface coating having a thickness of between about 50 and 200 nm, and having a very smooth structure with a roughness of less than 1 μm; focusing said laser energy of said selected exciter wavelength onto said at least one deposited particle as part of said spectroscopic identification; collecting backscattered light from said at least one deposited particle; filtering out said at least one exciter wavelength from said collected light; generating a spectrum of said filtered light using spectroscopic analysis techniques; and identifying a chemical composition of said at least one deposited particle in response to said generated spectrum.