The vibrational motions of atomic adsorbates on surfaces can be probed by helium atom scattering. The experimental observable is the dynamic structure factor, which shows an inelastic peak around the vibrational frequency of the isolated adsorbates known as the frustrated translational or T-mode peak. In this paper we develop a theory for the line shape of this peak, as well as for its temperat...

The combined effects of strain and phonon confinement are seen to explain why the Raman peak near 464 cm in CeO22y nanoparticles shifts to progressively lower energies and the lineshape of this feature gets progressively broader and asymmetric ~on the low-energy side! as the particle size gets smaller. The increasing lattice constant measured for decreasing particle size explains this Raman shi...

Self-mixing laser sensors require few components and can be used to measure velocity. The self-mixing laser sensor consists of a laser emitting a beam focused onto a rough target that scatters the beam with some of the emission re-entering the laser cavity. This 'self-mixing' causes measurable interferometric modulation of the laser output power that leads to a periodic Doppler signal spectrum ...

Using perturbation expansion of Maxwell equations with the nonlinear boundary condition, a generic propagation equation is derived to describe nonlinear effects, including spectral broadening of pulses, in graphene surface plasmon (GSP) waveguides. A considerable spectral broadening of an initial 100 fs pulse with 0.5 mW peak power in a 25 nm wide and 150 nm long waveguide is demonstrated. The ...

Ionization-assisted spectral broadening of high-energy 10.6 μm laser pulses in a gas-filled hollow waveguide is shown to yield single-cycle pulses with multiterawatt peak powers in the mid-IR. While the highest quality of pulse compression is achieved in the regime of weak ionization, careful management of complex ionization-assisted spectral broadening of guided-wave fields is the key to compr...

Introduction: Peak broadening recognized in X-ray diffraction (XRD) and micro-Raman (MRS) spectra of experimentally and naturally shock-metamorphosed carbonates from carbonate-target bo-lide impact structures has been shown to be a reliable indicator of impact-related shock-metamorphism [1-7]. However, studies have not yet shown whether this peak broadening is unique to or diagnostic of all car...

In this paper, we perform a theoretical study of processes that demonstrates additional time delay obtained by remodeling Brillouin gain spectrum, and we also study the main influence factors on pulse time delay and broadening, as well as analyze the ways which increases the delay, and further suppresses pulse broadening. The results show that by remodeling Brillouin gain spectrum, one obtains ...