Backscattered supercontinuum emission from high-intensity laser-plasma interactions.
We performed high-intensity subpicosecond laser-plasma interaction experiments to examine nonlinear scattering mechanisms in underdense plasmas. At incident laser intensities of 2 x 10(18) W/cm(2) the stimulated-Raman-backscattered spectrum exhibited an extremely broad, supercontinuumlike structure (Deltaomega/omega(0) > 1) extending from ~500 to >1200 nm (limited only by detector sensitivity). Large-amplitude modulations in the spectrum of the backscattered light were measured and are attributed to an interaction of the stimulated-Raman-scattered radiation with ion plasma waves.
Measurement of femtosecond ionization dynamics of atmospheric density gases by spectral blueshifting.
The new plasma diagnostic technique of spectral blueshifting of femtosecond pulses is used for the first time to analyze quantitatively the ionization of noble gases under the influence of intense, femtosecond illumination. The two processes of strong-field tunneling ionization and electron impact ionization are found to play competing roles on these time scales
Miniband formulation in Ge/Si quantum dot array
In this work, we estimate the coupling effect of miniband structure and density of states (DoS) resulting from different qunatum-dot physical parameters in a well-aligned Ge/Si quantum dot (QD) array fabricated by neutral beam etching technology. The density of QDs dominates the coupling effect and miniband’s bandwidth, the radius of QDs affects the magnitude of energy levels and miniband bandwidth, and the thickness of QDs has a great impact on the magnitude of energy levels. Among the different shapes of Ge/Si QDs, discoid QDs exhibit the most band crossing and broadest bandwith under the same physical parameters.