volume | PIER Journals

Abstract

Modulation methods such as homodyne and heterodyne detections are employed in A-SNOM in order to eliminate serious background effects from scattering fields. Usually, the frequency-modulated detection signal in apertureless scanning near-field optical microscopy (A-SNOM) is generally analyzed using a simple dipole-interaction model based only on the near-field interaction. However, the simulated A-SNOM spectra obtained using such models are in poor agreement with the experimental results since the effects of background signals are ignored. Accordingly, this study proposes a new phenomenological model for analyzing the A-SNOM detection signal in which the effects of both the dipole-interaction and the background fields are taken into account. It is shown that the simulated A-SNOM spectra for 6H-SiC crystal and polymethylmethacrylate (PMMA) samples are in good agreement with the experimental results. The validated phenomenological model is used to identify the experimental A-SNOM parameter settings which minimize the effects of background signals and ensure that the detection signal approaches the pure near-field interaction signal. Finally, the phenomenological model is used to evaluate the effects of the residual stress and strain in a SiC substrate on the corresponding A-SNOM spectrum.

1. Pohl, D. W., S. Denk, and M. Lanz, "Optical stethoscopy: Image recording with resolution λ/=20," J. Appl. Phys., Vol. 44, 651-653, 1984. Google Scholar

2. Jackson, J. D., Classical Electrodynamics, Wiley, 1999.

3. Patane, S., G. G. Gucciardi, M. Labardi, and M. Allegrini, "Apertureless near-field optical microscopy," Rivita Del Nuovo Cimento, Vol. 27, 1-46, 2004. Google Scholar

4. Wessel, J., "Surface-enhanced optical microscopy," J. Opt. Soc. Am., Vol. 2, 1538-1540, 1985.
doi:10.1364/JOSAB.2.001538 Google Scholar

5. Wickramasinghe, H. K. and C. C. Williams, "Apertureless near field optical microscope,", US Patent 4947034, 1990. Google Scholar

6. Inouye, Y. and S. Kawata, "Near-field scanning optical microscope with a metallic probe tip," Opt. Lett., Vol. 19, 159-161, 1994.
doi:10.1364/OL.19.000159 Google Scholar

7. Hillenbrand, R. and F. Keilmann, "Complex optical constants on a subwavelength scale," Phys. Rev. Lett., Vol. 85, 3029-3032, 2000.
doi:10.1103/PhysRevLett.85.3029 Google Scholar

8. Hillenbrand, R., B. Knoll, and F. Keilmann, "Pure optical contrast in scattering-type scanning near-field microscopy," J. Microsc., Vol. 202, 77-83, 2000.
doi:10.1046/j.1365-2818.2001.00794.x Google Scholar

9. Knoll, B. and F. Keilmann, "Enhanced dielectric contrast in scattering-type scanning near-field optical microscopy," Opt. Commun., Vol. 182, 321-328, 2000.
doi:10.1016/S0030-4018(00)00826-9 Google Scholar

10. Hudlet, S., S. Aubert, A. Bruyant, R. Bachelot, P. M. Adam, J. L. Bijeon, G. Lerondel, P. Royer, and A. A. Stashkevich, "Apertureless near field optical microscopy: A contribution to the understanding of the signal detected in the presence of background field," Opt. Commun., Vol. 230, 245-251, 2004.
doi:10.1016/j.optcom.2003.11.029 Google Scholar

11. Formanek, F., Y. D. Wilde, and L. Aigouy, "Analysis of the measured signals in apertureless near-field optical microscopy," Ultramicroscopy, Vol. 103, 133-139, 2005.
doi:10.1016/j.ultramic.2004.11.004 Google Scholar

12. Gucciardi, P. G., G. Bachelier, and M. Allegrini, "Far-field background suppression in tip-modulated apertureless near-field optical microscopy," J. Appl. Phys., Vol. 99, No. 124309, 2006. Google Scholar

13. Stefanon, I., S. Blaize, A. Bruyant, S. Aubert, G. Lerondel R. Bachelot, and P. Royer, "Heterodyne detection of guided waves using a scattering-type scanning near-field optical microscope," Opt. Express, Vol. 13, 15782-15796, 2007. Google Scholar

15. Chuang, C. H. and Y. L. Lo, "An analysis of heterodyne signals in apertureless scanning near-field optical microscopy," Opt. Express, Vol. 16, 17982-18003, 2008.
doi:10.1364/OE.16.017982 Google Scholar

16. Chuang, C.-H. and Y.-L. Lo, "Signal analysis of apertureless scanning near-field optical microscopy with superlens," Progress In Electromagnetics Research, Vol. 109, 83-106, 2010.
doi:10.2528/PIER10081102 Google Scholar

17. Cvitkovic, A., N. Ocelic, and R. Hillenbrand, "Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy," Opt. Express, Vol. 15, 8550-8565, 2007.
doi:10.1364/OE.15.008550 Google Scholar

18. Xie, H., Xie, H., F. M. Kong, and K. Li, "The electric field enhancement and resonance optical antenna composed of AU nanoparicles," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 4, 534-547, 2009.
doi:10.1163/156939309787612419 Google Scholar

19. Hamid, A.-K. and F. R. Cooray, "Scattering by a perfect electromagnetic conducting elliptic cylinder," Progress In Electromagnetics Research Letters, Vol. 10, 59-67, 2009.
doi:10.2528/PIERL09060301 Google Scholar

20. Mohamed, M. A., E. F. Kuester, M. Piket-May, and C. L. Holloway, "The field of an electric dipole and the polarizability of a conducting object embedded in the interface between dielectric materials," Progress In Electromagnetics Research B, Vol. 16, 1-20, 2009.
doi:10.2528/PIERB09050408 Google Scholar

21. Eroglu, A. and J. K. Lee, "Far field radiation from an arbitrarily oriented hertzian dipole in an unbounded electricaly gyrotropic medium," Progress In Electromagnetics Research, Vol. 89, 291-310, 2009.
doi:10.2528/PIER08122202 Google Scholar

22. Kalaee, P. and J. Rashed-Mohassel, "Investigation of dipole radiation pattern above a chiral media using 3D bi-FDTD approach," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 1, 75-86, 2009.
doi:10.1163/156939309787604706 Google Scholar

23. Zhang, S., S.-X. Gong, Y. Guan, J. Ling, and B. Lu, "A new approach for synthesizing both the radiation and scattering patterns of linear dipole antenna array," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 7, 861-870, 2010.
doi:10.1163/156939310791285137 Google Scholar

24. Laviada-Martinez, J., Y. Alvarez Lopez, and F. Las-Heras, "Efficient determination of the near-field in the vicinity of an antenna for the estimation of its safety perimeter," Progress In Electromagnetics Research, Vol. 103, 371-391, 2010.
doi:10.2528/PIER10031807 Google Scholar

25. Huber, A. J., A. Ziegler, T. Köck, and R. Hillenbrand, "Infrared nanoscopy of strained semiconductors," Nature Nanotechnology, Vol. 4, 153-157, 2008. Google Scholar

26. Aizpurua, J., T. Taubner, F. J. García de Abajo, M. Brehm and R. Hillenbrand, "Substrate-enhanced infrared near-field spectroscopy," Opt. Express, Vol. 16, 1529-1545, 2008.
doi:10.1364/OE.16.001529 Google Scholar

27. Walford, J. N., J. A. Porto, R. Carminati, J. J. Greffet, P. M. Adam, S. Hudlet, J. L. Bijeon, A. Stashkevich, and P. Royer, "Influence of tip modulation on image formation in scanning near-field optical microscopy," J. Appl. Phys., Vol. 89, 5159-5169, 2001.
doi:10.1063/1.1359153 Google Scholar

28. Gomez, L., R. Bachelot, A. Bouhelier, G. P. Wiederrecht, S. H. Chang, S. K. Gray, F. Hua, S. Jeon, J. A. Rogers, M. E. Castro, S. Blaize, I. Stefanon, G. Lerondel, and P. Royer, "Apertureless scanning near-field optical microscopy: A comparison between homodyne and heterodyne approaches," J. Opt. Soc. Am. B, Vol. 23, 823-833, 2006.
doi:10.1364/JOSAB.23.000823 Google Scholar

29. Lo, Y. L. and C. H. Chuang, "New synthetic-heterodyne demodulation for an optical fiber interferometry," IEEE J. Quantum Electro., Vol. 37, 658-663, 2001. Google Scholar

30. Bek, A., "Apertureless SNOM: A new tool for nano-optics,", Ph.D. Dissertation, Max Planck Institute for Solid State Research, Germany, 2004. Google Scholar

31. Palik, E. D., Handbook of Optical Constants of Solids, Academic, 1985.

32. Harima, H., S. Nakashima, and T. Uemura, "Raman-scattering from anisotropic LO-phonon-plasmon-coupled mode in n-type 4H-SiC and 6H-SiC," J. Appl. Phys., Vol. 78, 1996-2005, 1995.
doi:10.1063/1.360174 Google Scholar

33. Huber, A., N. Ocelic, T. Taubner, and R. Hillenbrand, "Nanoscale resolved infrared probing of crystal structure and of plasmonCphonon coupling," Nano Lett., Vol. 6, 774-778, 2006.
doi:10.1021/nl060092b Google Scholar

34. Liu, J. and Y. K. Vohra, "Raman modes of 6H polytype of siliconcarbide to ultrahigh pressures --- A comparison with silicon and diamond," Phys. Rev. Lett., Vol. 72, 4105-4108, 1994.
doi:10.1103/PhysRevLett.72.4105 Google Scholar

Dr. Chia-Chi Liao

Professor Yu-Lung Lo