By Topic

A study of background signals in terahertz apertureless near-field microscopy and their use for scattering-probe imaging

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

The purchase and pricing options are temporarily unavailable. Please try again later.
4 Author(s)
Astley, Victoria ; Department of Electrical and Computer Engineering, Rice University, MS 366, Houston, Texas 77251-1892, USA ; Hui Zhan ; Mendis, Rajind ; Mittleman, D.M.

Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.3141727 

Apertureless near-field microscopy is an imaging technique in which a small metal tip is held close to a surface, converting evanescent waves to propagating waves and permitting extreme subwavelength spatial resolution. This technique has recently been adapted for use in the terahertz region of the spectrum. Here, the interpretation of the measured signals and the suppression of background scattering can be complicated by the extremely broad bandwidth of the terahertz source and by the coherent (i.e., phase-sensitive) detection of the scattered radiation. We have analyzed the use of tip-sample distance modulation for the removal of background signals. We find that significant background signals, originating from scattering off the probe tip, can be observed even after modulation. These background signals result from path-length difference modulation, and thus are relevant when phase-sensitive detection is used. We use a dipole antenna model to explain the spatial variation in the scattered signal. Since this signal originates from the tip only, it can be used to characterize free-space terahertz wave fronts with subwavelength resolution.

Published in:

Journal of Applied Physics  (Volume:105 ,  Issue: 11 )