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Giant Second-Harmonic Generation Enhancement in the Presence of Tamm Plasmon-Polariton
B.I. A finog enov , V.O. Bessonov, and A.A. Fedyanin
Lom onosov M oscow St at e Uni versit y, 1 Leni nski e gory, 119991, M oscow, Russi a afi nogenov@nanolab.phys.m su.ru

Abstra ct: Giant enhancement of the second harmonic generation in metal/photonic cr ystal (PC) system obser ved in the vicinity of Tamm plasmon-polariton resonance due to str ong electromagnetic field localization at the metal and PC inter face.
OCIS codes: ( 350.4238) Nanophotonics and phot oni c cr yst als; (190.4350) Nonli near optics at sur faces

1 . Introduction Tamm p lasmon-polar itons (TPP) in photonic crystals (PC) are op tical analogues of electronic densit y localization at the boundar y of p eriodic atomic p otential [1 ]. These states manifest themselves exp erimentall y as narrow p eaks in transmittance sp ectra of metal/p hotonic cr ystal (Me/PC) systems [2 ]. The effects of second-harmonic generation (SHG) enhancement due to electromagnetic- field localization are well known in nonlinear optics. The localization can b e reached in the sp ectral region of surface- or local-plasmonsp olariton [3,4 ] or of microcavity-mode [5] resonance. Accor ding to Ref. [2 ] in the p resence of Tamm p lasmonp olariton, electromagnetic field is localized at the b oundar y of metal and PC. Thus TPP -induced SHG enhancement is exp ected. 2 . Samples and setup The studied samples consist of 6 p airs of ZrO2/SiO2 (aver age thicknesses 110 nm and 145 nm, respectivel y) quar terwavelength Samples are dep osited on q uartz substrate using thermal evaporation. Op timal thickness of the top most layer was calculated to be 225 nm, therefore additional 80 -nm layer of SiO2 was deposited on the samp le sur face. Then str uctur e was covered b y a 30-nm-thick gold film allowing good field localization in the TPP mode. As a source Ti:Sapphire laser was used, providing 130 fs pulses with 80 MHz rep etition r ate. Fundamental wavelength was tuned in the range of 720-800 nm. T he incident b eam was focused to the 40-m-wide spot at the samp le. Pump pulse fluence at the sample was about100Jcm-2. Angle of incidence to the sample was 2 0°. Experiment was set in pp combination of fundamental and second-harmonic (SH) radiation p olarization. Secondhar monic spectra were measured with 1-nm resolution. The SH b eam was collected thr ough a lens and a 9 -mmthick BG39 filter to reject any r esidual fundamental light. The signal was detected with a gated p hoton counter, each p oint being recorded for at least 2 0 s. 3 . Results and discussion Figure 1 shows transmittance sp ectr um (solid line) and SH sp ectrum (black circles) of the Au/PC samp le. The resonance near 774 nm in transmittance sp ectrum is associated with the excitation of the TPP. According to the theor y and numerical calculations, in the presence of TPP, electromagnetic field is localized at the inter face of metal and p hotonic cr ystal. Main part of SH in metals is generated b y the sur face, so enhancement of local electromagnetic field leads to enhancement of the SH signal from the metal film. SH spectrum of the 30 -nm-thick gold film is shown for the r eference with magenta tr iangles. The sp ectrum demonstrated no features and average signal level corresponds to the SH signal generated b y the Au/PC samp le out of the TPP resonance. Sharp peak in the SH spectrum of the Au/PC samp le is ob served in the vicinity of the TPP resonance. Maximum SH signal fr om the samp le is ob served at 7 74 nm. The 60 -times TPP-induced enhancement of the SH signal is achieved.


Fi g.1. (Color online) B lack circl es ­ experiment al SH spectr um of t heAu/ PC sampl e. Magent a triangl es ­ experi ment al S H spectrum of t he 30nm-thi ck gol d film. Red ( sol id) cur ve ­ experiment al li near tr ansmi ttance spectr um of t he Au/ PC sa mple.

4 . Conclusions In conclusion, the experimental p roof of SHG enhancement in Au/PC system in the presence of TPP is ob tained. . The 60-times TPP-induced enhancement of the SH signal is shown. This is an experimental evidence of the electromagnetic field localization in the TPP mode at the boundar y of metal and photonic crystal. 5 . References
[ [ [ [ [ 1] 2] 3] 4] 5] I .E. Tamm, J ETP 3, 34 (1933). A. Kavoki n, I . S hel ykh, and G. Mal puech, App. Phys. Lett . 87, 261105 (2005). H. J. Si mo n, D. E. Mit chell, and J. G. Wat son, P hys. Rev. Lett . 33, 1531 (1974). R. Ant oi ne, M. P ell ari n, B. P alpant et al ., J . App. P hys. 84, 4532 (1998) . T. V. D ol gova, A. I . Maidykovski, M. G. Martemyanov et al ., App. Phys. Lett . 81, 2725 ( 2002).