G. Korn

REGENERATIVE PULSE SHAPING AND AMPLIFICATION OF ULTRABROADBAND OPTICAL PULSES

Regenerative pulse shaping is used to alleviate gain narrowing during ultrashort-pulse amplification. Amplification bandwidths of ~ 100 nm, or nearly three times wider than the traditional gain-narrowing limit, are produced with a modified Ti:sapphire regenerative amplifier. This novel regenerative amplifier has been used to amplify pulses to the 5-mJ level with a bandwidth sufficient to support ~ 10-fs pulses.

Techniques for controlling gain narrowing during ultrashort-pulse amplification

Regenerative pulse shaping is used to overcome gain narrowing during ultrashort pulse amplification. We have demonstrated multiple spectral filters for broadening the amplified spectrum. We have produced amplified pulses with an energy of approximately 5 mJ and bandwidths of approximately 100 nm, or nearly 3 times wider than the gain narrowing limit of Ti:sapphire.

Generation of intense supershort optical pulses using ultrafast molecular phase modulation

Summary form only given. We have demonstrated a new method of single extremely short intense pulse generation using ultrafast molecular phase modulation in a hollow waveguide filled with impulsively excited Raman active gas for a probe pulse shorter than the molecular vibrational period. A continuous phase control of the second delayed pulse has been performed by changing the delay of the pump and the probe pulse within the molecular vibrational period. In addition we would like to point out that the second delayed pulse can be at other wavelengths.

Next generation ultrashort pulse lasers: Terawatts to Petawatts

Techniques for the control of femtosecond resolution phase and amplitude distortions during the amplification of 10‐fs optical pulses to joule‐level energies are discussed.

Group velocity-matched interactions in fs- nonlinear optics:enhanced high-order Raman scattering by impulsively excited vibrations

Summary form only given. We have recently proposed and demonstrated a new regime of fs-pulse stimulated Raman scattering (SRS). In this regime, the medium is prepared by an intense pump pulse with a duration shorter than the molecular vibrational period T/sub v/ = 2/spl pi///spl Omega//sub v/ (impulsive excitation). A low-intensity delayed injection pulse experiences phase modulation by the coherently oscillating vibrations, which leads to the generation of multiple sideband components /spl omega//sub n/ = /spl omega//sub 1/ + n /spl Omega//sub v/, (n = 0, /spl plusmn/1 ...). High efficiency of the side-band generation (up to 100%), tunability of the process, and the fact that the components are free of the influence of the deteriorating nonlinear effects (SPM, self-focusing etc.), suggest a wide range of potential applications of the technique in nonlinear optics and spectroscopy. The most intriguing feature of the SRS-regime is that the generated SRS-components are mutually coherent and can be used for the Fourier synthesis of sub-fs waveforms,,that has been recently demonstrated. In the paper we show that the scattering efficiency can be significantly increased by employing the dispersive properties of gas-filled hollow waveguides (HW).

Regenerative Pulse Shaping: A New Technique for Ultrabroadband Amplification

Regenerative pulse shaping is used to amplify sub-20 fs pulses, and to produce ~100-fs pulses centered at different wavelengths for difference frequency mixing in the 6–12 µm range.