نتایج جستجو برای: chirped laser
تعداد نتایج: 184926 فیلتر نتایج به سال:
A lidar system based on the coherent detection of oppositely chirped pulses generated using a 20 MHz mode locked laser and chirped fiber Bragg gratings is presented. Sub millimeter resolution ranging is performed with > 25 dB signal to noise ratio. Simultaneous, range and Doppler velocity measurements are experimentally demonstrated using a target moving at > 330 km/h inside the laboratory.
This paper presents recent results in the development of novel ultrafast technologies based on the generation and application of extremely chirped optical pulses. Linearly frequency-swept modelocked optical pulses of ns durations are generated, at the infrared telecommunications wavelength of 1.55 mm, by using chirped fiber Bragg gratings. The swept pulses appear as continuous wave signals, whi...
Hybrid femtosecond lasers combine the chirped pulse amplification (CPA) in laser media with optical parametric chirped pulsed amplification (OPCPA) in nonlinear crystals. A key feature of these systems consists in matching the parametric amplification gain bandwidth of nonlinear crystals to the spectral gain bandwidth of laser amplifying crystals. Gain bandwidths as broad as 150 nm can be obtai...
We demonstrate amplification of picosecond laser pulses to 40?mJ at a 2?kHz pulse repetition frequency (PRF) from a two-stage cryogenic chirped-pulse Yb:YAG amplifier, composed of a regenerative amplifier (RGA) and a two-pass booster amplifier. The RGA produces 8.2mJ of energy at 2kHz PRF and 13.2mJ at 1kHz PRF with excellent energy stability (approximately 0.3% rms) and beam quality (M(2)<1.1)...
ABSTRACT Spectral hole burning reduces sodium laser guide star efficiency. Due to photon recoil, atoms that are initially resonant with the single-frequency get Doppler shifted out of resonance, which return flux. Frequency-chirped (also known as frequency-swept) continuous-wave lasers have potential mitigate effect spectral and even increase efficiency beyond theoretical limit a laser. We inve...
This paper reports on a novel approach for producing high energy femtosecond pulses without external amplification. The so-called chirped-pulse oscillator ~CPO! concept is based on an extended-cavity oscillator, operating at small net positive intracavity group delay dispersion ~GDD!, over a broad spectral range by the use of chirped multilayer mirrors. The resultant chirped picosecond pulses a...
Approximate analytical chirped solitary pulse (chirped dissipative soliton) solutions of the one-dimensional complex cubic-quintic nonlinear Ginzburg-Landau equation are obtained. These solutions are stable and highly accurate under condition of domination of a normal dispersion over a spectral dissipation. The parametric space of the solitons is three-dimensional, that makes theirs to be easil...
Self-phase modulation in fiber amplifiers can significantly degrade the quality of compressed pulses in chirped pulse amplification systems. Parabolic pulses with linear frequency chirp are suitable for suppressing nonlinearities, and to achieve high peak power pulses after compression. In this paper, we present an active time domain technique to generate parabolic pulses for chirped pulse ampl...
We present a new mechanism for high-order harmonic generation by reflection of a laser beam from an overdense plasma, efficient even at moderate laser intensities (down to Igamma2 approximately 4x10(15) W cm-2 microm2). In this mechanism, a transient phase matching between the electromagnetic field and plasma oscillations within a density gradient leads to the emission of harmonics up to the pl...
A simple method for generating trains of high-contrast femtosecond pulses is proposed and demonstrated: a linearly polarized, frequency-chirped laser pulse is passed through a multiple-order wave plate and a linear polarizer. It is shown theoretically that this arrangement forms a train of laser pulses, and in experiments the production of a train of approximately 100 pulses, each of 200 fs dur...
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