Laser Pulses In Space Research Articles

0.35% THz pulse conversion efficiency achieved by Ti:sapphire femtosecond laser filamentation in argon at 1 kHz repetition rate

In this study, an optical setup for generating terahertz (THz) pulses through a two-color femtosecond laser filament was carefully designed to achieve a precise overlap of two-color laser pulses in space and time. β-barium borate (BBO), α-BBO, and a dual-wavelength plate were used to compensate the phase delay of the two-color lasers. Tilting of α-BBO could further realize the precise spatial overlap of the two beams by counteracting the walk-off effect. The maximum output THz pulse energy reached 21 μJ in argon gas when using a commercial Ti:sapphire laser with a pulse energy of 6 mJ at a 1 kHz repetition rate. The corresponding conversion efficiency exceeded 0.35%.

Spatiotemporal characterization of ultrashort laser pulses using spatially resolved Fourier transform spectrometry.

We present a method for characterizing ultrashort laser pulses in space and time, based on spatially resolved Fourier transform spectrometry. An unknown pulse is interfered with a delayed, spatially uniform reference on a CCD camera. The reference pulse is created by spatially filtering a portion of the unknown pulse. By scanning the delay between the two pulses, an interferogram is obtained at each pixel, allowing us to determine the spatially resolved phase difference between the unknown pulse and the reference pulse. High-resolution spatiotemporal characterization of an ultrashort pulse is demonstrated, and the sensitivity of the method to spatiotemporal coupling is shown for the case of a pulse with pulse front tilt.

Supercontinuum sources in a high-power femtosecond laserpulse propagating in liquids and gases

The mechanism of supercontinuum generation and the spatial distribution of its sources during the propagation of a high-power femtosecond laser pulse in liquids and gases are studied. The numerical simulation shows that the supercontinuum is generated due to self-phase modulation of the laser pulse in space and time in the presence of nonlinearity and wave effects. Supercontinuum sources are found to be located mainly in the ring structure of the laser pulse at the intensity minima. It is established that the efficiency of generation of the short-wavelength part of the supercontinuum during the propagation of the focused laser beam depends on the initial phase modulation and achieves a maximum when the compression length slightly exceeds the length of nonlinear focusing.

Tracking femtosecond laser pulses in space and time.

We show that the propagation of a femtosecond laser pulse inside a photonic structure can be directly visualized and tracked as it propagates using a time-resolved photon scanning tunneling microscope. From the time-dependent and phase-sensitive measurements, both the group velocity and the phase velocity are unambiguously and simultaneously determined. It is expected that this technique will find applications in the investigation of the local dynamic behavior of photonic crystals and integrated optical circuits.

Laser-synchrotron hybrid experiments A photon to tickle - A photon to poke

Abstract In this paper we present the preliminary results from a new experimental technique to synchronize the pulses from a mode-locked Nd-YAG laser to the light pulses in the VUV storage ring at the National Synchrotron Light Source (NSLS). We describe a method to electronically change the delay time between the laser pulses and the synchrotron pulses. We also illustrate a method to overlap the synchrotron pulses with the laser pulses in space and time. Preliminary results will be presented for two experiments.