Electron and trap dynamics in As-ion-implanted and annealed GaAs

The ultrafast dynamics of As-ion-implanted and annealed GaAs is investigated using transmission pump–probe measurements.Carrier recombination time was found to increase from 4 to 40 ps with increasing annealing temperature. At lower annealing temperatures, the transmitted optical signal is dominated by induced absorption and at higher annealing temperatures this effect is replaced by induced transparency.This work was supported in part by the EC INCOCOPERNICUS project ‘‘DUO—devices for ultrafast optoelectronics’’ and the Lithuanian Science and Study Foundation

Self-Guided Intense Laser Pulse Propagation in Air

We report on observation of self-guiding of picosecond laser pulses in air that produces large-scale self-phase modulation. The converging picosecond laser beam produced a confined filament over 3 m of propagation with the whitelight spectrum

Second harmonic optical vortex generation in air

We demonstrate second harmonic vortex generation in atmospheric pressure air using tightly focused femtosecond laser beam. The average second harmonic power is two orders of magnitude higher compared to previous reports

Noise reduction in 3D noncollinear parametric amplifier

We analytically find an approximate Bloch-Messiah reduction of a noncollinear parametric amplifier pumped with a focused monochromatic beam. We consider type I phase matching. The results are obtained using a perturbative expansion and scaled to a high gain regime. They allow a straightforward maximization of the signal gain and minimization of the parametric fluorescence noise. We find the fundamental mode of the amplifier, which is an elliptic Gaussian defining the optimal seed beam shape. We conclude that the output of the amplifier should be stripped of higher order modes, which are approximately Hermite-Gaussian beams. Alternatively, the pump waist can be adjusted such that the amount of noise produced in the higher order modes is minimized.Comment: 18 pages, 9 figures, accepted to Applied Physics

20-fs 1.6-mJ pulses from a cw-diode-pumped single-stage 1-kHz Yb amplifier

200-fs 2.5-mJ pulses from a fiber-oscillator-seeded DPSS Yb:CaF2 MOPA are spectrally broadened in Ar and recompressed to 20 fs using a pair of LAK14 prisms. Multi-millijoule 12-fs pulses are feasible upon higher-order spectral phase correction. © 2010 Optical Society of America

30-fs 1.6 mJ Pulses at a kHz repetition rate from a single stage DPSS Yb amplifier

200-fs 2.5-mJ pulses from a cw-diode-pumped Yb:CaF2 MOPA are spectrally broadened in Ar and recompressed to 30 fs at 980 nm using a prism pair. Multi-millijoule 12-fs pulses are feasible upon higher-order spectral phase correction. © 2010 Optical Society of America