Near-field localization by ultrashort femtosecond light pulses has been investigated using simple geometrical nanoapertures. The apertures employ circular, rhombic, and triangular shapes to localize the distribution of surface plasmon. To understand the geometrical effect on the localization, aperture length and period of the nanoapertures were varied. Aperture length was shown to affect the pe...

We study BPS dominated loop amplitudes in M-theory on T 2. For this purpose we generalize the concept of helicity supertraces to nine spacetime dimensions. These traces distinguish between various massive supermultiplets and appear as coefficients in their one-loop contributions to n-graviton scattering amplitudes. This can be used to show that only ultrashort BPS multiplets contribute to the R...

We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum-frequency mixing of the output from an optical parametric oscillator (λ= 1400-1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generat...

Ultrashort electron bunches are crucial for an increasing number of applications, however, diagnosing their longitudinal phase space remains a challenge. We propose a new method that harnesses the strong electric fields present in a laser driven plasma wakefield. By transversely displacing driver laser and witness bunch, a streaking field is applied to the bunch. This field maps the time inform...

Ultrashort terahertz (THz) beam is often affected by spatio-temporal distortion due to its long wavelength, and this coupling will degrade the focusing effect. Here, we develop a numerical model for calculating vector of ultrashort pulses with arbitrary spatial temporal distribution, which adopt diffraction integral coherent spectrum superposition methods. Leveraging it, broadband pulse can be ...

The interaction of Li– with an ultrashort intense laser pulse is investigated by solving the time-dependent Schrödinger equation (TDSE) in the dipole approximation using a two-active electron approach. We describe the numerical solution of the TDSE and give a more detailed presentation of a technique for obtaining angular distributions for double ionization by intense ultrashort laser pulses. W...

We demonstrate how a steady-state train of ultrashort radiation pulses can be produced utilizing a new free-electron laser ~FEL! configuration, the injection-locked regenerative klystron amplifier ~IRKA!. This configuration consists of two elements: ~1! a prebuncher, which microbunches the electron beams at the desired output wavelength, and ~2! a multipass FEL operated at a very small cavity d...

Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a twophoton transition. The absorptive vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than but quickly surpassing the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanis...

I present a numerical package, written in MATLAB, which provides a simplified scripting interface for simulating a host of ultrashort pulse propagation phenomena. With the proliferation of ultrashort laser technologies, the demand for efficient and accurate simulations has grown significantly. Here I introduce a linear-operator-based formalism for nonlinear pulse propagation beyond the slowly-v...