G. Hays

Broad-spectrum neodymium-doped laser glasses for high-energy chirped-pulse amplification

We have investigated two novel laser glasses in an effort to generate high-energy, broad-spectrum pulses from a chirped-pulse amplification Nd:glass laser. Both glasses have significantly broader spectra (>38 nm FWHM) than currently available Nd:phosphate and Nd:silicate glasses. We present calculations for small signal pulse amplification to simulate spectral gain narrowing. The technique of spectral shaping using mixed-glass architecture with an optical parametric chirped-pulse amplification front end is evaluated. Our modeling shows that amplified pulses with energies exceeding 10 kJ with sufficient bandwidth to achieve 120 fs pulsewidths are achievable with the use of the new laser glasses. With further development of current technologies, a laser system could be scaled to generate one exawatt in peak power.

Multiterawatt laser-linac facility

Summary form only given. Recent progress in the generation and amplification of femtosecond pulses has made it possible to achieve peak powers of the order of tens of terawatts with relatively modest laser energy (<10 J). As a result, compact, multiterawatt lasers can be built at modest expense. Such lasers are of great interest for relativistic laser-plasma interaction research, for production of ultrafast X-rays, hard X-rays and /spl gamma/-rays for radiography, and for advanced electron acceleration research. We are currently developing a Ti:sapphire chirped pulse amplification laser, called Falcon. This laser is being constructed near the LLNL 100 MeV electron linear accelerator and, ultimately, is synchronized with this linac with sub-picosecond temporal accuracy, Such a facility permits a range of advanced experiments in which intense laser pulses interact with high peak current bunches of relativistic electrons. To achieve this synchronization part of the Falcon laser pulse is used to produce the electron beam in a photoinjector electron gun which injects electrons into the main accelerator. Furthermore, the RF of the S-band linac is slaved to the laser oscillator.

An analysis of broad-spectrum pulse amplification from mixed Nd:glass amplifiers

We present results in a comprehensive analysis of gain shaping from Nd:glass amplifiers in an effort to generate near 100 fs pulses in chirped pulse amplification. We discuss relative gain balance between the two media.

Time Resolved Asymmetrically Enhanced Third Harmonic Generation from Noble-Gas Cluster Explosions

We studied asymmetrically enhanced third harmonic generation from a noble-gas clustered jet heated with high intensity lasers using pump-probe techniques. When enhanced due to resonance and increased coherence length, third harmonic generation becomes temporarily anisotropic.

Dynamic Acceleration Effects in Explosions of Laser Irradiated Heteronuclear Clusters

Based on the model for heteronuclear cluster explosions developed by Last and Jortner, we present experimental confirmation of the theoretically predicted ion energy enhancement of the light ion species in methane clusters

Time Resolved, Phase-Matched Harmonic Generation from Exploding Noble Gas Clusters

Third-harmonic generation from noble-gas clusters by ultrafast probe pulses is more sharply-enhanced than linear absorption following heating by an ultrafast pump pulse, in good agreement with simulations of cluster expansion and collective electron dynamics with phase matching consideration.

Time resolved harmonic generation from noble-gas cluster explosions

We have studied the dynamics of noble-gas clusters heated with high intensity lasers using pump-probe techniques. Enhanced third harmonic production has been observed for a particular time delay between the pump and the probe based upon the relative cluster size.