ИСТИНА

The resonant interaction between the surface charge and the electromagnetic field of the light constitutes the surface plasmons polaritons and gives rise to its unique properties. Femtosecond-scale polarization state shaping has been experimentally found recently in optical response of a plasmonic nanograting by means of time-resolved Stokes polarimetry [1] based on the intensity autocorrelation scheme that is the most common technique to examine ultrashort pulses because it is easy to set up and use. But the information of the electric field phase is lost in such a measurement. Frequency-Resolved Optical Gating (FROG) which was invented by R. Trebino et al. [2] is one of the technique for retrieving both the amplitude and phase of the field. In this work ultrafast dynamics of surface plasmons in one-dimensional plasmonic crystals is studied experimentally by using FROG technique. One-dimensional perforated metal film fabricated by laser interference lithography is used to study the excitation of surface plasmon-polaritons. The FROG spectrograms show very distinctive peculiarities for the case of surface plasmon excitation configuration: for p-polarized incident light there are significant changes as the pulse width and spectral characteristics at wavelengths near edges of the plasmonic band gap. The amplitude and phase of the pulses are extracted from the spectrogram series. The phase sensitivity of the technique allows us to reconstruct non-symmetric plasmon-assisted reshaping of the femtosecond pulses. [1] M. R. Shcherbakov, P. P. Vabishchevich, V. V. Komarova, T. V. Dolgova, V. I. Panov, V. V. Moshchalkov, and A. A. Fedyanin "Ultrafast Polarization Shaping with Fano Plasmonic Crystals", Phys. Rev. Lett. 108, 253903 (2012). [2] R. Trebino, K.W. DeLong, D.N. Fittinghoff, J.N. Sweetser, M.A. Krumbügel, B.A. Richman, and D.J. Kane, “Measuring ultrashort laser pulses in the time-frequency domain using frequency-resolved optical gating”, Rev.Sci.Instrum. 68(9), 3277 (1997).