Two-step femtosecond laser pulse train fabrication of nanostructured substrates for highly surface-enhanced Raman scattering.

A simple and repeatable method using femtosecond laser pulse train to fabricate nanostructured substrates with silver nanoparticles over a large area for surface-enhanced Raman scattering is reported. The method involves two steps: (1) femtosecond laser pulse train micromachining and roughening and (2) femtosecond laser processing of the substrates in a silver nitrate solution. Surface modification is investigated experimentally by varying the time delay of the double femtosecond laser pulse train.

Portable bacterial identification system based on elastic light scatter patterns.

Background: Conventional diagnosis and identification of bacteria requires shipment of samples to a laboratory for genetic and biochemical analysis. This process can take days and imposes significant delay to action in situations where timely intervention can save lives and reduce associated costs. To enable faster response to an outbreak, a low-cost, small-footprint, portable microbial-identification instrument using forward scatterometry has been developed.