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Laser-wakefield acceleration offers the promise of a compact electron accelerator for generating a multi-GeV electron beam using the huge field gradient induced by an intense laser pulse, compared to conventional rf accelerators. However, the energy and quality of the electron beam from the laser-wakefield accelerator have been limited by the power of the(More)
High-contrast, 30 fs, 1.5 PW laser pulses are generated from a chirped-pulse amplification (CPA) Ti:sapphire laser system at 0.1 Hz repetition rate. The maximum output energy of 60.2 J is obtained, at a pump energy of 120 J, from a booster amplifier that is pumped by four frenquency-doubled Nd:glass laser systems. During amplification, parasitic lasing is(More)
An investigation has been made into the effect produced by photo-induced pyrimidine cross-links upon the secondary structure of DNA. We have studied the effect of uv irradiation upon the B in equilibrium A transition in DNA brought about by a change of solvent from 70 to 80% ethanol. Circular dichroism (CD) was used to monitor the conformational changes.(More)
Coherent short-wavelength radiation from laser-plasma interactions is of increasing interest in disciplines including ultrafast biomolecular imaging and attosecond physics. Using solid targets instead of atomic gases could enable the generation of coherent extreme ultraviolet radiation with higher energy and more energetic photons. Here we present the(More)
We demonstrate a long-term operation with reduced phase noise in the carrier-envelope-phase (CEP) stabilization process by employing a double feedback loop and an improved signal detection in the direct locking technique [Opt. Express 13, 2969 (2005)]. A homodyne balanced detection method is employed for efficiently suppressing the dc noise in the f-2f beat(More)
We have developed a practical solution to implement the direct locking method for the carrier-envelope phase (CEP) stabilization of femtosecond laser pulses and achieved 24-hour CEP stabilization without realignment of any optical components. The direct locking method realizes the CEP stabilization in the time domain by directly quenching the beat signal(More)
We propose and demonstrate a tunable Q-switched erbium doped fiber laser with a digitally controlled micro-mirror array device. The tunable and pulsed output of the laser was achieved by the pixelated spatial modulation of the micro-mirror array. The wavelength tuning from 1530 nm to 1555 nm was shown with wavelength selectivity of ~0.1 nm and the pulsed(More)
We have demonstrated broadening of the phase-matching bandwidth in a periodically poled Ti:LiNbO3 (Ti:PPLN) channel waveguide Lambda = 16.6 microm) by using a temperature-gradient-control technique. With this technique, we have achieved a second-harmonic phase-matching bandwidth of more than 13 nm in a 74-mm-long Ti:PPLN waveguide, which has a 0.21-nm(More)
Particle acceleration using ultraintense, ultrashort laser pulses is one of the most attractive topics in relativistic laser-plasma research. We report proton and/or ion acceleration in the intensity range of 5×10(19) to 3.3×10(20) W/cm2 by irradiating linearly polarized, 30-fs laser pulses on 10-to 100-nm-thick polymer targets. The proton energy scaling(More)