New microcavity substrates for enhancing Raman signals of microscopic samples

A novel method for improving the detection limit of normal Raman spectra of chemicals using a micro-Raman system and pico-liters volume is presented. A micro-cavity substrate uses various mechanisms that collectively improve the normal Raman signal from the sample without surface-enhanced Raman scattering (SERS) enhancement. The microcavity substrate enhances the entire Raman spectra of the molecules under investigation and maintains the relative intensity ratios of the various Raman bands. This feature of maintaining the overall integrity of the Raman features during signal enhancement makes the micro-cavity substrate ideal for forensic science applications requiring chemical detection of residual traces and other applications requiring low sample volumes and concentrations. It will be further shown that micro-cavities coated with nano films of gold and silver takes advantage of both SERS and micro-cavity method and significantly improve the detection limits of samples.

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