Abstract
The ability of using scattering-type near-field scanning optical microscopy (s-NSOM) to characterize amplitude and phase of optical near fields was investigated. We employ numerical simulations to compute signals scattered by the tip, using a bowtie nano-aperture as the example, and compare with the data obtained from s-NSOM measurements. Through demodulation of higher order harmonic signals, we show that, with the increasing order of harmonic signals, both the simulated and measured near fields are in closer agreement with the anticipated near field results. The polarization-resolved detection also helps to establish a tip-dependent transfer matrix that relates the local field components with the s-NSOM signals, which characterizes the scattering of the tip with respect to different field components. This work illustrates the importance of using higher order signals in obtaining near field in an s-NSOM measurement.
Highlights
Scattering type NSOM (s-NSOM) is an optical technology for achieving super-resolution on the order of 10 nm, which is largely independent of wavelength [1, 2]
We employ numerical simulations to compute signals scattered by the tip, using a bowtie nano-aperture as the example, and compare with the data obtained from scattering-type near-field scanning optical microscopy (s-NSOM) measurements
Through demodulation of higher order harmonic signals, we show that, with the increasing order of harmonic signals, both the simulated and measured near fields are in closer agreement with the anticipated near field results
Summary
Scattering type NSOM (s-NSOM) is an optical technology for achieving super-resolution on the order of 10 nm, which is largely independent of wavelength [1, 2]. A sharp tip in the vicinity of the sample serves as a scatterer that converts evanescent near fields to propagating radiation, making near fields detectable by far field detectors. An important undertaking for sNSOM is to suppress the large background signal, which is a result of the light scattering from the sample and the tip shaft [3]. This is achieved by modulating the near field interaction through sinusoidally oscillating the tip and collecting data using interferometric methods [4 6]. Interferometric techniques are incorporated to resolve both amplitude and phase of the near fields
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
