An absorption-based superconducting nanodetector as a near-field optical probe Qiang Wang* and Michiel J. A. de Dood Institute of Physics, Leiden University, Niels Bohrweg 2, Leiden, 2333CA, The Netherlands *
[email protected]
Abstract: We investigate the use of a superconducting nano-detector as a novel near-field probe. In contrast to conventional scanning near-field optical microscopes, the nano-detector absorbs and detects photons in the near-field. We show that this absorption-based probe has a higher collection efficiency and investigate the details of the interaction between the nano detector and the dipole emitter. To this end, we introduce a multipole model to describe the interaction. Calculations of the local density of states show that the nano-detector does not strongly modify the emission rate of a dipole, especially when compared to traditional metal probes. ©2013 Optical Society of America OCIS codes: (180.4243) Near-field microscopy; (230.0040) Detectors; (270.5570) Quantum detectors.
References and links 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.
R. C. Dunn, “Near-field scanning optical microscopy,” Chem. Rev. 99(10), 2891–2928 (1999). V. Sandoghdar, B. Buchler, P. Kramper, S. Götzinger, O. Benson, and M. Kafesaki, “Scanning near-field optical studies of photonic devices,” in Photonic Crystals: Advances in Design, Fabrication, and Characterization, K. Busch, S. Lölkes, R. B. Wehrspohn and H. Föll eds. (Wiley-VCH Verlag GmbH & Co. KGaA, 2006). F. Keilmann and R. Hillenbrand, “Near-field microscopy by elastic light scattering from a tip,” Philos. Transact. A Math. Phys. Eng. Sci. 362(1817), 787–805 (2004). T. Kalkbrenner, M. Ramstein, J. Mlynek, and V. Sandoghdar, “A single gold particle as a probe for apertureless scanning near-field optical microscopy,” J. Microsc. 202(1), 72–76 (2001). B. Hecht, B. Sick, U. P. Wild, V. Decker, R. Zenobi, O. J. F. Martin, and D. W. Pohl, “Scanning near-field optical microscopy with aperture probes: fundamentals and applications,” J. Chem. Phys. 112(18), 7761–7774 (2000). C. H. Henry and R. F. Kazarinov, “Quantum noise in photonics,” Rev. Mod. Phys. 68(3), 801–853 (1996). E. Betzig and R. J. Chichester, “Single molecules observed by near-field scanning optical microscopy,” Science 262(5138), 1422–1425 (1993). G. N. Gol’tsman, O. Okunev, G. Chulkova, A. Lipatov, A. Semenov, K. Smirnov, B. Voronov, A. Dzardanov, C. Williams, and R. Sobolewski, “Picosecond superconducting single-photon optical detector,” Appl. Phys. Lett. 79(6), 705–707 (2001). D. Bitauld, F. Marsili, A. Gaggero, F. Mattioli, R. Leoni, S. J. Nejad, F. Lévy, and A. Fiore, “Nanoscale optical detector with single-photon and multiphoton sensitivity,” Nano Lett. 10(8), 2977–2981 (2010). A. Rasmussen and V. Deckert, “New dimension in nano-imaging: breaking through the diffraction limit with scanning near-field optical microscopy,” Anal. Bioanal. Chem. 381(1), 165–172 (2005). F. Zenhausern, M. P. O’Boyle, and H. K. Wickramasinghe, “Apertureless near-field optical microscope,” Appl. Phys. Lett. 65(13), 1623–1625 (1994). A. V. Zayats and V. Sandoghdar, “Apertureless near-field optical microscopy via local second-harmonic generation,” J. Microsc. 202(1), 94–99 (2001). T. Vo-Dinh, J. P. Alarie, B. M. Cullum, and G. D. Griffin, “Antibody-based nanoprobe for measurement of a fluorescent analyte in a single cell,” Nat. Biotechnol. 18(7), 764–767 (2000). Y. Zhang, A. Dhawan, and T. Vo Dinh, “Design and fabrication of fiber-optic nanoprobes for optical sensing,” Nanoscale Res. Lett. 6, 18–23 (2011). J. Smajic and C. Hafner, “Numerical analysis of a SNOM tip based on a partially cladded optical fiber,” Opt. Express 19(23), 23140–23152 (2011). H. A. Bethe, “Theory of diffraction by small holes,” Phys. Rev. 66(7-8), 163–182 (1944). I. S. Averbukh, B. M. Chernobrod, O. A. Sedletsky, and Y. Prior, “Coherent near field optical microscopy,” Opt. Commun. 174(1-4), 33–41 (2000). C. F. Bohren and D. R. Huffman, “Particles small compared with the wavelength,” in Absorption and scattering of light by small particles. (Wiley & Sons, 1983). B. Knoll and F. Keilmann, “Enhanced dielectric contrast in scattering-type scanning near-field optical microscopy,” Opt. Commun. 182(4-6), 321–328 (2000).
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20. D. W. Lynch and W. R. Hunter, “Comments on the optical constants of metals and an introduction to the data for several metals,” in Handbook of Optical Constants of Solids I, E. D. Palik, ed. (Academic, 1998). 21. E. F. C. Driessen and M. J. A. de Dood, “The perfect absorber,” Appl. Phys. Lett. 94(17), 171109 (2009). 22. M. Esslinger and R. Vogelgesang, “Reciprocity theory of apertureless scanning near-field optical microscopy with point-dipole probes,” ACS Nano 6(9), 8173–8182 (2012). 23. A. J. L. Adam, N. C. J. van der Valk, and P. C. M. Planken, “Measurement and calculation of the near field of a terahertz apertureless scanning optical microscope,” J. Opt. Soc. Am. B 24(5), 1080–1090 (2007). 24. J. D. Jackson, “Multipoles, electrostatics of macroscopic media, dielectrics,” in Classical Electrodynamics. (Wiley & Sons, 1983). 25. L. Novotny and B. Hecht, “Dipole emission near planar interfaces,” in Principles of Nano-optics. (Cambridge University Press, 2006). 26. J. D. Jackson, “Radiating systems, multipole fields and radiation,” in Classical Electrodynamics. (Wiley & Sons, 1983). 27. J. D. Jackson, “Maxwell equations, macroscopic electromagnetism, conservation laws,” in Classical Electrodynamics. (Wiley & Sons, 1983). 28. K. H. Drexhage, “Influence of a dielectric interface on fluorescence decay time,” J. Lumin. 1(2), 693–701 (1970). 29. K. H. Drexhage, “Interaction of light with monomolecular dye layers,” Prog. Opt. 12, 165–232 (1974). 30. R. R. Chance, A. Prock, and R. Silbey, “Molecular fluorescence and energy transfer near interfaces,” Adv. Chem. Phys. 37, 1–65 (1978). 31. K. Joulain, R. Carminati, J. Mulet, and J. Greffet, “Definition and measurement of the local density of electromagnetic states close to an interface,” Phys. Rev. B 68(24), 245405 (2003). 32. K. Tanabe, H. Asano, Y. Katoh, and O. Michikami, “Ellipsometric and optical reflectivity studies of reactively sputtered NbN thin films,” J. Appl. Phys. 63(5), 1733 (1988).
1. Introduction Near-field optical microscopes have been used to probe the fluorescence of a single molecule and the evanescent near-field of a large variety of nanophotonic structures [1,2]. Because near-field probes interact with evanescent waves the resolution of these microscopes is not limited by the diffraction limit that holds for propagating waves. Conventional near-field microscopes probe the optical near-field with a metal tip [3], a metal particle [4] or a metal coated tip with a sub-wavelength hole [5]. These probes are positioned in the near-field and scanned in the lateral directions. These tips either scatter the light directly into the optical far field, or through a sub-wavelength aperture connected to an optical fiber where it is detected by a photosensitive detector in the far-field. To attain sub-wavelength lateral resolution, the size of the aperture or tip should be smaller than the wavelength. This makes near-field probes based on scattering inherently inefficient because light scattering from sub-wavelength metal particles is an inefficient process. For particles that are much smaller than the wavelength, Rayleigh scattering occurs and the scattering decreases as d6/λ4, where d is the dimension of the particle and λ is the wavelength. This low collection efficiency makes near-field studies of quantum optics an extremely challenging task, because detection of weak light with a small collection efficiency (i.e., missing out many photons) introduces noise [6]. Similarly in experiments on single molecules the total number of photons emitted by a molecule is given by the ratio τ1/2/τrad, where τ1/2 is the half life of a molecule due to bleaching and τrad is the radiative lifetime [7]. Since the absorption of a small particle scales with its volume, i.e. as d3, an intrinsically much more efficient near-field nano-detector can be constructed. Recently, superconducting nano-detectors have been demonstrated that absorb a single photon and create a measurable electronic pulse for each absorbed photon [8]. This type of detector is based on optical absorption and detection of single photons directly in the near-field. In this paper we consider a detector made of a 4 nm thick NbN film grown on a GaAs substrate, i.e. identical to the square nano-detector reported in the Ref. 9. Photons can be detected only in the constricted area where the current through the detector is close to the critical current of the superconductor at cryogenic temperatures. 2. Scattering and absorption by a near-field probe Conventional scanning near-field optical microscopes (SNOMs) can be subdivided into two major types: aperture based SNOMs and scattering type SNOMs [10]. The aperture based
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Received 3 Dec 2012; revised 26 Jan 2013; accepted 26 Jan 2013; published 6 Feb 2013
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SNOMs make use of a subwavelength hole in a metal film or metal-clad fiber tip [11–15]. The transmission through a subwavelength hole in a good conductor is extremely low and is proportional to a6/λ4 (a/λ
