Ultra-broadband frequency shifting of laser pulses in a square multicore chalcogenide fiber.

The process of Raman frequency shifting of out-of-phase laser pulses in fibers with a square configuration of weakly coupled cores having two or more zero dispersion wavelengths has been studied. The use of out-of-phase distributions in multicore fibers makes it possible to increase pulse energies by orders of magnitude in comparison with the case of single-core fibers. Conditions for the stability of out-of-phase laser pulses are determined and confirmed by numerical simulations.

Photoinduced large polaron transport and dynamics in organic-inorganic hybrid lead halide perovskite with terahertz probes.

Organic-inorganic hybrid metal halide perovskites (MHPs) have attracted tremendous attention for optoelectronic applications. The long photocarrier lifetime and moderate carrier mobility have been proposed as results of the large polaron formation in MHPs. However, it is challenging to measure the effective mass and carrier scattering parameters of the photogenerated large polarons in the ultrafast carrier recombination dynamics.

Measuring heavy metal ions in water using nature existed microalgae as medium based on terahertz technology.

Heavy metal pollution in water seriously affects human health. The disadvantages of traditional metal ion detection methods involve long and cumbersome chemical pretreatment in the early stage, and large volume of samples. In this study, microalgae were used as the medium, and terahertz spectroscopy technology was employed to collect the changes of material components in it, so as to deduce the types and concentrations of heavy metal pollution in water.

Excitation of graphene surface plasmons polaritons by guided-mode resonances with high efficiency.

An Otto-like configuration for the excitation of graphene surface plasmon polaritons (GSPPs) is proposed. The configuration is composed of a metallic grating-dielectric-waveguide structure and a monolayer graphene with a subwavelength vacuum gap between them. The evanescent field located at the bottom surface of the dielectric waveguide corresponding to grating-coupled guided-mode resonances (GMRs) is utilized to efficiently excite the highly confined GSPPs.

Terahertz-frequency temporal differentiator enabled by a high-Q resonator.

Terahertz (THz) fundamental "building blocks" equivalent to those used in multi-functional electronic circuits are very helpful for actual applications in THz data-processing technology and communication. Here, we theoretically and experimentally demonstrate a THz temporal differentiator based on an on-chip high-quality (Q) factor resonator. The resonator is made of low-loss high-resistivity silicon material in a monolithic, integrated platform, which is carefully designed to operate near the critical coupling region.

Metal-graphene hybridized plasmon induced transparency in the terahertz frequencies.

In this work, metal-graphene hybridized plasmon induced transparency (PIT) is systematically studied in the proposed simple metal/dielectric/graphene system. The PIT effect is the result of the coupling between the bright dipolar modes excited in the graphene regions under the shorter metallic bars and the dark quadrupolar modes excited in the graphene regions under the longer metallic bars. The coupled Lorentz oscillator model is used to help explain the physical origin of the PIT effect.

Beyond nonlinear saturation of backward Raman amplifiers.

Backward Raman amplification is limited by relativistic nonlinear dephasing resulting in saturation of the leading spike of the amplified pulse. Pump detuning is employed to mitigate the relativistic phase mismatch and to overcome the associated saturation. The amplified pulse can then be reshaped into a monospike pulse with little precursory power ahead of it, with the maximum intensity increasing by a factor of two.