Design of a sub-13-fs, multi-gigawatt chirped pulse optical parametric amplification system

We present a design for phase-locked chirped pulse optical parametric amplification of ultra-short pulses based on Ti:sapphire. A realistic description is given by measuring the oscillator pulse (11.6fs, 4nJ) with SPIDER and numerically propagating it through the whole chirped pulse amplification system. The interaction is modeled with a full three-dimensional code and compression is ray-trace optimized to yield 12.7-fs, 98-μJ pulses with 1mJ of pump energy. The design is scalable in energy (e.g. 1mJ with 10-mJ pump) and is exclusively based on commercially available component

Two-dimensional organization of a large number of stationary optical filaments by adaptive wave front control

We present an adaptive technique for the formation of multiple co-propagating and stationary filaments in a gaseous medium. Wavefront shaping of the initial beam is performed using a deformable mirror to achieve a complete two-dimensional control of the multi-spot intensity pattern in the laser focus. The spatial organization of these intensity spots yields reliable formation of up to five stable and stationary filaments providing a test bed for fundamental studies on multiple filamentatio

Single-shot dynamics of pulses from a gas-filled hollow fiber

We present measurements of the performance characteristics of few-cycle laser pulses generated by propagation through a gas-filled hollow fiber. The pulses going into the fiber and the compressed pulses after the fiber were simultaneously fully characterized shot-by-shot by using two kHz SPIDER setups and kHz pulse energy measurements. Output-pulse properties were found to be exceptionally stable and pulse characteristics relevant for non-linear applications like high-harmonic generation are discusse

Generation of intense, carrier-envelope phase-locked few-cycle laser pulses through filamentation

Intense, well-controlled light pulses with only a few optical cycles start to play a crucial role in many fields of physics, such as attosecond science. We present an extremely simple and robust technique to generate such carrier-envelope offset (CEO) phase locked few-cycle pulses, relying on self-guiding of intense 43-fs, 0.84mJ optical pulses during propagation in a transparent noble gas. We have demonstrated 5.7-fs, 0.38mJ pulses with an excellent spatial beam profile and discuss the potential for much shorter pulses. Numerical simulations confirm that filamentation is the mechanism responsible for pulse shortening. The method is widely applicable and much less sensitive to experimental conditions such as beam alignment, input pulse duration or gas pressure as compared to gas-filled hollow fiber

Numerical simulations for performance optimization of a few-cycle terawatt NOPCPA system

We present a systematic numerical design and performance study of an ultra-broadband noncollinear optical parametric chirped pulse amplification (NOPCPA) system. Using a split-step Fourier approach, we model a three-stage amplifier system which is designed for the generation of 7 fs pulses with multi-terawatt peak intensity. The numerical results are compared with recent experimental data. Several important aspects and design parameters specific to NOPCPA are identified, and the values of these parameters required to achieve optimal working conditions are investigated. We identify and analyze wavelength-dependent gain saturation effects, which are specific to NOPCPA and have a strong influence on the parametric amplification process. © Springer-Verlag 2007

Micromachining of hardened Portland cement pastes using femtosecond laser pulses

ISSN:1359-5997ISSN:0025-5432ISSN:1871-687

Intense THz radiation produced in organic salt crystals for high-field applications

Organic stilbazolium salt crystals pumped by intense, ultrashort mid-infrared laser have been investigated for efficient THz generation by optical rectification. In this paper we present our latest results in view of the generation of single-cycle and high-field THz transient in the THz gap (0.1-10 THz). The organic rectifiers like DAST, OH1 and DSTMS combine extremely large optical susceptibility with excellent velocity matching between the infrared pump and the THz radiation. Our simple collinear conversion scheme provides THz beams with excellent focusing properties and single cycle electric field larger than 1.5 MV/cm and magnetic field strength beyond 0.5 Tesla. The source can potentially cover the full THz gap at field strength which is barely provided by other THz sources. The THz pulse is carrier-envelope phase stable and the polarity of the field can be easily inverted. © 2013 Copyright SPIE

Laser-driven generation of intense single-cycle THz field

We report on laser-based, high power single-cycle THz source. The THz radiation is generated by four-wave mixing in plasma and by optical rectification in organic salt crystal pumped by powerful optical parametric amplifier. The first approach permits the generation of electric field of hundreds of kV/cm at central frequency of 0.7 THz. The second technique allows the synthesis of an electric field exceeding 1 MV/cm paired with an unprecedented conversion efficiency of more than 2%, at frequency of 2 THz. The presented sources can be focused to a diffraction-limited spot and are suitable-versatile tool for time resolved THz experiment. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE)

Chirped pulses sum frequency generation for deep - UV picosecond pulse shaping

We show by experiments and simulations that properly chirped laser pulses enable efficient and broadband sum frequency generation in nonlinear crystals. We achieved high energy, picosecond deep-UV pulses with spectral width one order of magnitude greater than the acceptance bandwidth of the nonlinear interaction. The broad spectrum supports shaping of ps flat-top deep-UV pulses with short rise- and fall-time, which are optimal for driving high brightness photocathode electron guns. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE)