Optical properties and enhancement factors of the tips for apertureless near-field optics

D Mehtani, N Lee, R D Hartschuh, A Kisliuk, M D Foster, A P Sokolov, F Čajko, I Tsukerman
2006 Journal of Optics. A, Pure and applied optics  
Resonant excitation of surface plasmons of a metal or metal-coated tip is crucial for achieving high enhancement of an optical signal with apertureless near-field optics. However, it remains a challenge to measure the optical spectrum of a tip with sub-wavelength dimensions. We present a technique based on total internal reflection microscopy to measure the optical properties of tips. A dependence of the optical resonance on the metal deposited is shown for silver-coated and gold-coated tips.
more » ... ese tips were also used to measure the tip-enhanced Raman spectra of silicon and a polymer blend of poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT/PSS) at 514.5 and 647 nm incident wavelengths. Qualitative agreement was observed between the tip-enhanced Raman spectra and the optical resonance of the tip measured with the technique developed.
doi:10.1088/1464-4258/8/4/s19 fatcat:5zxdpbcoorcp3eibgvw2zxzyrq