Heterodyne detection signal analysis in apertureless scanning Near-field optical microscopy

C. H. Chuang, Y. L. Lo

研究成果: Conference contribution

摘要

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.

原文English
主出版物標題2008 Proceedings of the ASME Micro/Nanoscale Heat Transfer International Conference, MNHT 2008
頁面889-894
頁數6
DOIs
出版狀態Published - 2008
事件1st ASME Micro/Nanoscale Heat Transfer International Conference, MNHT08 - Tainan, Taiwan
持續時間: 2008 1月 62008 1月 9

出版系列

名字2008 Proceedings of the ASME Micro/Nanoscale Heat Transfer International Conference, MNHT 2008
PART B

Other

Other1st ASME Micro/Nanoscale Heat Transfer International Conference, MNHT08
國家/地區Taiwan
城市Tainan
期間08-01-0608-01-09

All Science Journal Classification (ASJC) codes

  • 材料力學
  • 材料科學(全部)
  • 凝聚態物理學
  • 原子與分子物理與光學

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