Nonplasmonic surface enhanced Raman spectroscopy using silica microspheres

Surface enhanced Raman spectroscopy is presented using a nonplasmonic mechanism based on whispering gallery modes in silica microspheres. Sensitive Raman analysis of molecular films is demonstrated by using 5-10 mu m sized silica spheres. The advantages of this nonplasmonic approach are the active substrate is chemically inert, thermally stable, and relatively simple to fabricate. Applications include trace organic analysis particularly for in situ planetary instruments that require robust sensors with consistent response. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3493657]