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Ultrathin semiconductors on metals constitute color filters, which selectively absorb wavelength ranges of incident light. This paper demonstrates that these coatings are attractive for tunable color devices by reversibly switching ultrathin phase-change materials on gold between two colors with femtosecond laser pulses. The optical contrast is enhanced(More)
The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond timescale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the(More)
Recently, phase-change materials (PCMs) have gained a lot of interest in the field of active metamaterials and plasmonics due to their switchable optical properties. In the infrared spectral range the huge contrast in the refractive index between an amorphous and a crystalline phase can be employed for nonvolatile tuning of nanoantenna or metasurface(More)
The interactions between electrons and lattice vibrations are fundamental to materials behaviour. In the case of group IV-VI, V and related materials, these interactions are strong, and the materials exist near electronic and structural phase transitions. The prototypical example is PbTe whose incipient ferroelectric behaviour has been recently associated(More)
Terahertz pulses are applied as an all-optical bias to ferroelectric thin-film BiFeO3 while monitoring the time-dependent ferroelectric polarization through its nonlinear optical response. Modulations in the intensity of the second harmonic light generated by the film correspond to on-off ratios of 220× gateable on femtosecond timescales. Polarization(More)
Phase-change materials are technologically important due to their manifold applications in data storage. Here we report on ab initio molecular dynamics simulations of crystallization of the phase change material Ag4In3Sb67Te26 (AIST). We show that, at high temperature, the observed crystal growth mechanisms and crystallization speed are in good agreement(More)
Pump-probe optical reflectivity and terahertz transmission measurements have been used to investigate time resolved sub-threshold photo-induced effects in crystalline and amorphous GeSbTe films at MHz repetition rates. The reflectivity in both phases exhibits long-lived modulations consistent with the sign of the changes that occur upon switching but of(More)
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