Ultrashort pulses were produced at 248 nm by using a transverse-discharge KrF* excimer laser as a high-energy amplifier system. Input pulses for the amplifier system were obtained by upconverting the output of a modelocked visible dye laser to the ultraviolet by using nonlinear crystals. Pulses of up to 20 mJ; in energy with 10-30-psec duration were obtained at 10 pulses/sec. The output pulse w...

We report the first numerical demonstration of the generation of multiple superradiance pulses in a slippage-dominant freeelectron laser amplifier. In this simulation, the 1 and 2 multiple radiation-pulses are created from the deformation of the longitudinal phase space. Our simulation confirmed controllability over the temporal profile of these pulses, and paves the way for applying this techn...

We present experimental results of the amplification of strongly amplitude-modulated chirped pulses resulting from the coherent addition of two delayed short pulses. The nonlinearities in the amplifier chain induce a temporal diffraction resulting in prepulses and postpulses, in addition to the two main pulses when compressed. Simultaneously, temporal-resolved and spectral-resolved output pulse...

A fiber amplifier that generates nearly transform-limited sub-picosecond pulses and greater than 100 W average power at 1.3-GHz repetition rate is described. Modest stretching of the seed pulses allows the amplifier to be operated in the linear regime. The amplified and dechirped pulses exhibit excellent beam quality, and can be frequency-doubled to produce green pulses at 65 W average power. D...

We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration, we employ the generated anti-Stokes pulses as reference pulses in an interferometric coherent anti-...

We have demonstrated a new method of generating pulses of freely propagating THz electromagnetic radiation. The resulting 380 fs pulses are the shortest directly measured THz pulses in free space to date and are more powerful than those generated by Hertzian dipoles or by resonant dipole antennas. Temporal features as short as 190 fs were observed on these THz radiation pulses and thereby, illu...

We demonstrate the use of an aperiodic quasi-phase-matching (QPM) grating to generate second-harmonic pulses that are stretched or compressed relative to input pulses at the fundamental frequency. We frequency doubled an externally chirped erbium-doped fiber laser generating 17-ps (FWHM) pulses at 1560nm to produce near-transform-limited 110-fs (FWHM) pulses at 780nm by use of a 5-cm-long lithi...

We report results from experiments with a pseudo-one-dimensional Belousov-Zhabotinsky reaction that employs 1,4-cyclohexanedione as its organic substrate. This excitable system shows traveling oxidation pulses and pulse trains that can undergo complex sequences of propagation failures. Moreover, we present examples for i breathing pulses that undergo periodic changes in speed and size and ii ba...

We report the generation of ultrabroadband pulses spanning the 50-130 THz frequency range via phase-matched difference frequency mixing within the broad spectrum of sub-10 fs pulses in LiIO(3). Model calculations reproduce the octave-spanning spectra and predict few-cycle THz pulse durations less than 20 fs. The broad applicability of this scheme is demonstrated with 9-fs pulses from a Ti:sapph...

Indoor diffuse optical intensity channels are bandwidth constrained due to the multiple reflected paths between the transmitter and the receiver which cause considerable inter-symbol interference (ISI). The transmitted signal amplitude is inherently non-negative, being a light intensity signal. All optical intensity root Nyquist pulses are timelimited to a single symbol interval which eliminate...