Abstract
The THz radiation emission of Au-coated nanogratings (fused silica substrate, 30 nm Au layer thickness, 500 nm grating constant) upon fs laser irradiation (785 nm, 150 fs, 1 kHz, ≤1 mJ/pulse) is observed in both directions along the laser beam axis (forward and backward) and for both, illumination of the Au/air or the Au/silica interface. THz radiation along the laser beam propagation is emitted in a narrow solid angle of about 15° fwhm independent on the laser pulse fluence, the angle of incidence and the nanograting profile. The bar width and groove depth of the nanograting as well as the angle of laser beam incidence strongly affect the THz radiation yield. The energy of single THz light pulses is measured absolutely (2 fJ in the 0.3–0.38 THz range) using a highly sensitive and fast superconducting transition edge sensor. The bi-directional emission of THz radiation is in agreement with the model assumption of surface plasmon polaritons propagating simultaneously on both Au layer interfaces (Au/air and Au/silica).
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References
M. Tonouchi, Cutting-edge terahertz technology. Nat. Photonics 1, 97–105 (2007)
C.A. Schuttenmaer, Exploring dynamics in the far-infrared with terahertz spectroscopy. Chem. Rev. 104, 1759–1779 (2004)
M. Brucherseifer, M. Nagel, P. Haring-Bolivar, H. Kurz, A. Bosserhoff, R. Büttner, Label-free probing of the binding state of DNA by time-domain terahertz sensing. Appl. Phys. Lett. 77, 4049–4051 (2000)
S. Hunsche, M. Koch, I. Brener, M.C. Nuss, THz near-field imaging. Opt. Commun. 150, 22–26 (1998)
E.J. Heilweil, J.E. Maslar, W.A. Kimes, N.D. Bassim, P.K. Schenck, Characterization of metal oxide nanofilm morphologies and composition by terahertz transmission spectroscopy. Opt. Lett. 34, 1360–1362 (2009)
T. May, S. Anders, V. Zakosarenko, M. Starkloff, H. G. Meyer, G. Thorwirth, E. Kreysa, A superconducting terahertz imager. In Proceedings of the SPIE, vol 6549, p. 65490D (2007).
T. Kleine-Ostmann, P. Dawson, K. Pierz, G. Hein, M. Koch, Room-temperature operation of an electrically driven terahertz modulator. Appl. Phys. Lett. 84, 3555 (2004)
T. May, V. Zakosarenko, R. Boucher, E. Kreysa, H.G. Meyer, Superconducting bolometer array with SQUID readout for submillimetre wavelength detection. Supercond. Sci. Technol. 16, 1430–1433 (2003)
B. Ferguson, X.C. Zhang, Materials for terahertz science and technology. Nat. Mater. 1, 26–33 (2002)
C. Sirtori, C. Gmachl, F. Capasso, J. Faist, D.L. Sivco, A.L. Hutchinson, A.Y. Cho, Long-wavelength (8–11.5 μm) semiconductor lasers with waveguides based on surface plasmons. Opt. Lett. 23, 1366–1368 (1998)
J. Alton, H.E. Beere, J. Fowler, E.H. Linfield, and D.A. Ritchie, Low-threshold superlattice quantum cascade laser emitting at λ = 103 μm and operating up to 70 k in continuous wave. In Proceedings of the SPIE, 5354, vol 5354, p.129 (2005).
E. Bründermann, D.R. Chamberlin, E.E. Haller, High duty cycle and continuous terahertz emission from germanium. Appl. Phys. Lett. 76, 2991–2993 (2000)
T. Löffler, T. Hahn, M. Thomson, F. Jacob, H. Roskos, Large-area electro-optic ZnTe terahertz emitters. Opt. Express 13, 5353–5362 (2005)
D.J. Cook, R.M. Hochstrasser, Intense terahertz pulses by four-wave rectification in air. Opt. Lett. 25, 1210–1212 (2000)
T. Bartel, P. Gaal, K. Reimann, M. Woerner, T. Elsaesser, Generation of single-cycle THz transients with high electric-field amplitudes. Opt. Lett. 30, 2805–2807 (2005)
D.H. Auston, K.P. Cheung, P.R. Smith, Picosecond photoconducting hertzian dipoles. Appl. Phys. Lett. 45, 284–286 (1984)
S. Hoffmann, M. Hofmann, E. Brundermann, M. Havenith, M. Matus, J.V. Moloney, A.S. Moskalenko, M. Kira, S.W. Koch, S. Saito, K. Sakai, Four-wave mixing and direct terahertz emission with two-color semiconductor lasers. Appl. Phys. Lett. 84, 3585–3587 (2004)
G.H. Welsh, K. Wynne, Generation of ultrafast terahertz radiation pulses on metallic nanostructured surfaces. Opt. Express 17, 2470–2480 (2009)
G.H. Welsh, N.T. Hunt, K. Wynne, Terahertz-pulse emission through laser excitation of surface plasmons in a metal grating. Phys. Rev. Lett. 98, 026803 (2007)
F. Kadlec, P. Kuzel, J.L. Coutaz, Optical rectification at metal surfaces. Opt. Lett. 29, 2674–2676 (2004)
F. Kadlec, P. Kuzel, J.L. Coutaz, Study of terahertz radiation generated by optical rectification on thin gold films. Opt. Lett. 30, 1402–1404 (2005)
F. Garwe, A. Schmidt, G. Zieger, T. May, K. Wynne, U. Hübner, M. Zeisberger, W. Paa, H. Stafast, H.G. Meyer, Bi-directional terahertz emission from gold coated nanogratings by excitation via femtosecond laser pulses. Appl. Phys. B 102, 551–554 (2011)
G. Ramakrishnan, P.C.M. Planken, Percolation-enhanced generation of terahertz pulses by optical rectification on ultrathin gold films. Opt. Lett. 36, 2572–2574 (2011)
P.Y. Han, X.C. Zhang, Free-space coherent broadband terahertz time-domain spectroscopy. Meas. Sci. Technol. 12, 1747–1756 (2001)
M. Kuttge, F.J. Garcíade Abajo, A. Polman, How grooves reflect and confine surface plasmon polaritons. Opt. Express 17, 10385–10392 (2009)
K.D. Irwin, An application of electrothermal feedback for high resolution cryogenic particle detection. Appl. Phys. Lett. 66, 1998–2000 (1995)
Y. Gao, M.K. Chen, C.E. Yang, Y.C. Chang, S. Yin, R. Hui, P. Ruffin, C. Brantley, E. Edwards, C. Luo, Analysis of terahertz generation via nanostructure enhanced plasmonic excitations. J. Appl. Phys. 106, 074302 (2009)
H. Raether, Surface plasmons on smooth and rough surfaces and on gratings, vol 111 of Springer Tracts in modern physics (Springer, Berlin, 1988)
J. Moreland, A. Adams, P.K. Hansma, Diffraction efficiency and electron microscopy of large amplitude holographic gratings. Opt. Commun. 45, 11–16 (1983)
I.R. Hooper, J.R. Sambles, Coupled surface plasmon polaritons on thin metal slabs corrugated on both surfaces. Phys. Rev. B 70, 045421 (2004)
E. Popov, N. Bonod, S. Enoch, Comparison of plasma surface waves on shallow and deep metallic 1d and 2d gratings. Opt. Express 15, 4224–4237 (2007)
J. Le Perchec, P. Quemerais, A. Barbara, T. Lopez-Rios, Why metallic surfaces with grooves a few nanometers deep and wide may strongly absorb visible light. Phys. Rev. Lett. 100, 066408 (2008)
E.N. Economou, Surface plasmons in thin films. Phys. Rev. 182, 539–553 (1969)
F. Garwe, U. Bauerschäfer, A. Csaki, A. Steinbrück, K. Ritter, A. Bochmann, J. Bergmann, A. Weise, D. Akimov, G. Maubach, K. König, G. Hüttmann, W. Paa, J. Popp, W. Fritzsche, Optically controlled thermal management on the nanometer length scale. Nanotechnology 19, 055207 (2008)
K. Sakai, (ed.), Terahertz optoelectronics, vol 97. In Topics in applied physics (Springer, Berlin, 2005).
G. Klatt, F. Hilser, W. Qiao, M. Beck, R. Gebs, A. Bartels, K. Huska, U. Lemmer, G. Bastain, M.B. Johnston, M. Fischer, J. Faist, T. Dekorsy, Terahertz emission from lateral photo-dember currents. Opt. Express 18, 4939–4947 (2010)
Acknowledgments
We thank Dr. J. Bergmann, M. Schubert, A. Reinhard and C. Schmidt from the Institute of Photonic Technology, Jena, Germany, for helpful discussions and technical support, respectively. We are grateful for the sample characterization conducted by D. Schelle from the University of Jena, Germany, using their focused ion beam facility and scanning electron microscope. The authors thank K. Wynne, University of Strathclyde, UK, for our fruitful cooperation. The authors acknowledge support by the Thuringian ministry of education, science and culture (TeLIGHT, B714-09059).
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Schmidt, A., Garwe, F., Hübner, U. et al. Experimental characterization of bi-directional terahertz emission from gold-coated nanogratings. Appl. Phys. B 109, 631–642 (2012). https://doi.org/10.1007/s00340-012-5230-3
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DOI: https://doi.org/10.1007/s00340-012-5230-3