TY - JOUR
T1 - Analytical analysis of modulated signal in apertureless scanning near-field optical microscopy
AU - Chuang, C. H.
AU - Lo, Y. L.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2007/11/26
Y1 - 2007/11/26
N2 - Eliminating background-scattering effects from the detected signal is crucial in improving the performance of super-high-resolution apertureless scanning near-field optical microscopy (A-SNOM). Using a simple mathematical model of the A-SNOM detected signal, this study explores the respective effects of the phase modulation depth, the wavelength and angle of the incident light, and the amplitude of the tip vibration on the signal contrast and signal intensity. In general, the results show that the background-noise decays as the order of the Bessel function increases and that higher-order harmonic frequencies yield an improved signal contrast. Additionally, it is found that incident light with a longer wavelength improves the signal contrast for a constant order of modulation frequency. The signal contrast can also be improved by reducing the incident angle of the incident light. Finally, it is demonstrated that sample stage scanning yields an improved imaging result. However, tip scanning provides a reasonable low-cost and faster solution in the smaller scan area. The analytical results presented in this study enable a better understanding of the complex detected signal in A-SNOM and provide insights into methods of improving the signal contrast of the A-SNOM measurement signal.
AB - Eliminating background-scattering effects from the detected signal is crucial in improving the performance of super-high-resolution apertureless scanning near-field optical microscopy (A-SNOM). Using a simple mathematical model of the A-SNOM detected signal, this study explores the respective effects of the phase modulation depth, the wavelength and angle of the incident light, and the amplitude of the tip vibration on the signal contrast and signal intensity. In general, the results show that the background-noise decays as the order of the Bessel function increases and that higher-order harmonic frequencies yield an improved signal contrast. Additionally, it is found that incident light with a longer wavelength improves the signal contrast for a constant order of modulation frequency. The signal contrast can also be improved by reducing the incident angle of the incident light. Finally, it is demonstrated that sample stage scanning yields an improved imaging result. However, tip scanning provides a reasonable low-cost and faster solution in the smaller scan area. The analytical results presented in this study enable a better understanding of the complex detected signal in A-SNOM and provide insights into methods of improving the signal contrast of the A-SNOM measurement signal.
UR - http://www.scopus.com/inward/record.url?scp=36749010159&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=36749010159&partnerID=8YFLogxK
U2 - 10.1364/OE.15.015782
DO - 10.1364/OE.15.015782
M3 - Article
C2 - 19550863
AN - SCOPUS:36749010159
VL - 15
SP - 15782
EP - 15796
JO - Optics Express
JF - Optics Express
SN - 1094-4087
IS - 24
ER -