Optical pulse compression to 3.4 fs in the monocycle region by feedback phase compensation

We compensated for chirp of optical pulses with an over-one-octave bandwidth (495-1090 nm; center wave-length of 655.4 nm) produced by self-phase modulation in a single argon-filled hollow fiber and generated 3.4-fs, 1.56 optical-cycle pulses (500 nJ, 1-kHz repetition rate). This was achieved with a feedback system combined with only one 4-f phase compensator with a spatial light modulator and a significantly improved phase characterizer based on modified spectral phase interferometry for direct electric-field reconstruction. To the best of our knowledge, this is the shortest pulse in the visible-to-infrared region

Optical pulse compression to 5.0 fs by use of only a spatial light modulator for phase compensation

We experimentally demonstrate the generation of 5.0-fs optical pulses (2.5μJ, 1-kHz repetition rate), using only a spatial light modulator for phase compensation. Pulse compression of the broadband pulse (500-1000 nm) from an argon-filled capillary fiber is achieved with a liquid-crystal spatial light modulator without any prechirp compensation. The output pulse width is found to be 4.1 fs by a fringe-resolved autocorrelator fitted with a transform-limited pulse and to be 5.0 fs by second-harmonic generation frequency-resolved optical gating with marginal correction. It is to our knowledge the shortest pulse ever generated by use of only a spatial light modulator for phase compensation

Pulse compression of white-light continuum generated by induced phase modulation in a conventional glass fiber

The 530-880-nm continuum pulse with a greatly asymmetric temporal profile over 500 fs and a spectral phase variation over 150 rad, which was generated by induced phase modulation (IPM) as well as self-phase modulation in a conventional fused-silica fiber, was compressed to 7.8 fs by a feedback technique. Fundamental (a center wavelength of 800 nm, a duration of 80 fs, a pulse energy of 64 nJ) and signal pulses (a center wave-length of 670 nm, a duration of 80 fs, a pulse energy of 65 nJ) produced by one common femtosecond source with an optical parametric amplifier were copropagated in the fiber under an optimum delay time between the two pulses. The computer-controlled feedback system that combines a 4-f phase compensator with a spatial light modulator and a modified spectral phase interferometry for a direct electric-field reconstruction, automatically compensated for not only the conventional nonlinear chirp (group-delay dispersion and its higher-order dispersion) but also the frequency-independent group-delay (first-order phase dispersion), both of which are essential for pulse compression by use of the IPM effect

The potential of copy number gains and losses, detected by array-based comparative genomic hybridization, for computational differential diagnosis of B-cell lymphomas and genetic regions involved in lymphomagenesis

The findings of this study suggest that data of copy number gains and losses obtained with array CGH might be employed for computational differential diagnosis of B-cell lymphomas