Relativistic intensity few-cycle beamline for laser-matter interactions

Abstract

This thesis presents the development of a high-energy, few-cycle laser beamline designed for investigating the interaction of few-cycle laser pulses with materials, including ordered nanostructures. To achieve the increased spectral bandwidth necessary to generate few-cycle (sub-10 fs) pulses, broadening and post-compression is performed utilizing a hollow-capillary fiber (HCF) filled with helium gas. A >2 TW peak power is achieved with 6.9 fs duration pulses at 15 mJ, which results in a relativistic focused intensity of 6.5x1018 W/cm2. Additionally, to the authors best knowledge, this result is the highest peak power achieved utilizing stretched flexible HCFs (SF-HCFs) and is the first to utilize a 1 mm bore diameter SF-HCF in the 800 nm wavelength range. The broadening stage is also run in an uncommon reverse gradient mode, generally only utilized for resonant dispersive wave emission/propagation. Exceptional day-to-day throughput of 87% is achieved. In preparation for experiments and applications, plasma diagnostics were developed (electron kinetic energy spectrometer and X-ray spectrometer) to characterize the laser-matter interactions. A laser contrast enhancement relying on the cross-polarized wave (XPW) generation nonlinearity is in progress, and future peak power upgrades to 5 TW and 10 TW are being considered.