scholarly journals Near-field transmission matrix microscopy for mapping high-order eigenmodes of subwavelength nanostructures

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Eunsung Seo ◽  
Young-Ho Jin ◽  
Wonjun Choi ◽  
Yonghyeon Jo ◽  
Suyeon Lee ◽  
...  
2019 ◽  
Author(s):  
Jeffrey A. Housman ◽  
Gaetan K. Kenway ◽  
James C. Jensen ◽  
Cetin C. Kiris

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 54
Author(s):  
Jianzhong Li ◽  
Yide Wang ◽  
Cédric Le Bastard ◽  
Zongze Wu ◽  
Shaoyang Men

In this paper, an efficient high-order propagator method is proposed to localize near-field sources. We construct a specific non-Hermitian matrix based on the high-order cumulant of the received signals. With its columns and rows, we can obtain two subspaces orthogonal to all the columns of two steering matrices, respectively, with which the estimation of the directions of arrival (DOA) and ranges of near-field sources can be achieved. Different from other methods, the proposed method needs only one matrix for estimating two parameters separately, therefore leading to a smaller computational burden. Simulation results show that the proposed method achieves the same performance as the other high order statistics-based methods with a lower complexity.


Author(s):  
C. H. Chuang ◽  
Y. L. Lo

Apertureless scattering near-field optical microscopy (A-SNOM) is generally performed using a heterodyne detection technique since it provides a higher signal-to-noise (S/N) ratio than homodyne detection. Accordingly, this study constructs a robust interference-based model of the detection signal which takes account of both the tip enhancement phenomena and the tip reflective background electric field to analyze the amplitude and phase of heterodyne detection signals at different harmonics of the tip vibration frequency. The analytical results indicate that the high-order harmonic tip scattering noise decays more rapidly with a high-order Bessel function for small phase modulation depths than the near-field interaction signal. It is also shown that the signal contrast improves as the wavelength of the illuminating light source is increased or the incident angle is reduced. As compared with homodyne technique, it can be found the signal contrast is much improved in visible region in heterodyne technique. The results presented in this study provide an improved understanding of the complex signal detected in the heterodyne A-SNOM technique and suggest potential means of improving its S/N ratio such that the signal contrast of heterodyne A-SNOM can be improved.


Author(s):  
Jiangang Cai ◽  
Shutian Deng ◽  
Peng Xie ◽  
Chaoqun Liu

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