Pulse duration

About: Pulse duration is a research topic. Over the lifetime, 19429 publications have been published within this topic receiving 286507 citations.

Dual Q switching and laser action at 1.06 and 1.44 microm in a Nd(3+):YAG-Cr(4+):YAG oscillator at 300 K.

Abstract: We report what is to our knowledge the first dual operation comprising laser action and Q switching of Cr(4+):YAG pumped intracavity by a Nd:YAG laser. This technique produced dual 1.06- and 1.44-microm pulses with 35- and 200-ns pulse widths, respectively. The Nd:YAG rod was pumped by a 1-ms flash-lamp pulse, resulting in a train of 1.06- and 1.44-microm pulse pairs at approximately a 30-kHz rate.

Investigation of a millimeter-wavelength-range relativistic diffraction generator

Abstract: A theoretical and experimental study has been made of the operation of a millimeter-wavelength-range sectional relativistic diffraction generator (RDG). Microwave power transported into the atmosphere with the peak parameters of 3.5 and 4.5 GW at the wavelengths of 6.5 to 6.8 mm and 9 to 11.3 mm, respectively, has been obtained. The power at the generator output, up to a horn antenna, has reached 7 and 9 GW for each of the regimes, respectively, the electronic efficiency being equal to approximately 30%. Plasma formed in a slow-wave structure of the RDG is shown to be of considerable importance for radiation pulse duration limitation. Experiments aimed at increasing the pulse duration up to 0.7 mu s have been performed. Theoretical investigation of the beam interaction with a slow-wave structure field has shown that the generation frequency may be determined by the resonance features due to the transverse motion of beam electrons. >

Generation of 36-femtosecond pulses from a ytterbium fiber laser

Abstract: By optimizing the cavity dispersion map, 1.5-nJ pulses as short as 36 fs are obtained from a Yb-doped fiber laser. Residual higher-order dispersion currently limits the pulse duration, and it should be possible to generate pulses as short as 25–30 fs with Yb-doped fiber.

Experimental investigation of ultrashort pulse laser-induced breakdown thresholds in aqueous media

Abstract: Laser-induced breakdown (LIE) thresholds are determined for pulse durations of 2.4 ps, 400 fs, and 100 fs at 580 mn in high purity water, saline and tap water. The dependence of LIE irradiance thresholds on pulse duration, optical wavelength, and focal volume is examined, and the experimental data obtained is compared with a theoretical model. The slopes of the probability curves calculated are compared with mechanisms for LIE, namely avalanche ionization, multiphoton initiated avalanche ionization, and multiphoton ionization. Lastly, the dependence of the peak breakdown electric field on pulse duration and focal volume is empirically determined and compared with previous work.

Three-dimensional carrier-dynamics simulation of terahertz emission from photoconductive switches

Abstract: A semi-classical Monte Carlo model for studying three-dimensional carrier dynamics in photoconductive switches is presented. The model was used to simulate the process of photoexcitation in GaAs-based photoconductive antennas illuminated with pulses typical of mode-locked Ti:Sapphire lasers. We analyzed the power and frequency bandwidth of THz radiation emitted from these devices as a function of bias voltage, pump pulse duration and pump pulse location. We show that the mechanisms limiting the THz power emitted from photoconductive switches fall into two regimes: when illuminated with short duration ( 40 fs) pulses, screening is the primary power-limiting mechanism. A discussion of the dynamics of bias field screening in the gap region is presented. The emitted terahertz power was found to be enhanced when the exciting laser pulse was in close proximity to the anode of the photoconductive emitter, in agreement with experimental results. We show that this enhancement arises from the electric field distribution within the emitter combined with a difference in the mobilities of electrons and holes.