arXiv subjects

J. J. Pigeon

Publications and source records attributed to J. J. Pigeon.

4 recordsLinked to original sources

arXiv2026

Wavefront shaping of terahertz radiation using two-color flying-focus pulses with time-dependent focal velocities

Properly phased two-color laser pulses drive photoionization currents that emit broadband THz radiation. With a conventional two-color pulse, the ionization front travels at a nearly constant superluminal velocity, generating THz radiation with conical wavefronts at a Cherenkov-like angle. Here we show that the dynamic intensity peak of a two-color ultrashort flying-focus pulse can be used to control the shape of the THz wavefronts. Simulations demonstrate that non-uniform motion of the intensity peak and the ionization front it drives result in a time-dependent emission angle that determines the wavefront shape. A decelerating intensity peak, in particular, enables the generation of THz radiation with parabolic wavefronts that are well suited for collection and focusing.

physics.optics↗

arXiv2025

Path to a Single-Stage, 100-GeV Electron Beam via a Flying-Focus-Driven Laser-Plasma Accelerator

Dephasingless laser wakefield acceleration (DLWFA), a novel laser wakefield acceleration concept based on the recently demonstrated "flying focus" technology, offers a new paradigm in laser-plasma acceleration that could advance the progress toward a TeV linear accelerator using a single-stage system without guiding structures. The recently proposed NSF OPAL laser facility could be the transformative technology that enables this grand challenge in laser-plasma acceleration. We review the viable parameter space for DLWFA based on the scaling of its performance with laser and plasma parameters, and we compare that performance to traditional laser wakefield acceleration. These scalings indicate the necessity for ultrashort, high-energy laser architectures such as NSF OPAL to achieve groundbreaking electron energies using DLWFA. Initial results from MTW-OPAL, the platform for the 6-J DLWFA demonstration experiment, show a tight, round focal spot over a distance of 3.7 mm. New particle-in-cell simulations of that platform indicate that using hydrogen for DLWFA reduces the amount of laser light that is distorted due to refraction at ionization fronts. An experimental path, and the computational and technical design work along that path, from the current status of the field to a single-stage, 100-GeV electron beam via DLWFA on NSF OPAL is outlined. Progress along that path is presented.

physics.plasm-ph↗

arXiv2023

Programmable and arbitrary-trajectory ultrafast flying focus pulses

"Flying focus" techniques produce laser pulses with dynamic focal points that travels distances much greater than a Rayleigh length. The implementation of these techniques in laser-based applications requires the design of optical configurations that can both extend the focal range and structure the radial group delay. This article describes a method for designing optical configurations that produce ultrashort flying focus pulses with arbitrary-trajectory focal points. The method is illustrated by several examples that employ an axiparabola for extending the focal range and either a reflective echelon or a deformable mirror-spatial light modulator pair for structuring the radial group delay. The latter configuration enables rapid exploration and optimization of flying foci, which could be ideal for experiments.

physics.optics↗

arXiv2015

High-power, mid-infrared, picosecond pulses generated by compression of a CO2 laser beat-wave in GaAs

We report on the generation of a train of ~ 2 ps, 10 um laser pulses via multiple four-wave mixing and compression of an infrared laser beat-wave propagating in the negative group velocity dispersion region of bulk GaAs and a combination of GaAs and NaCl. The use of a 200 ps, 106 GHz beat-wave, produced by combining laser pulses amplified on the 10P(20) and 10P(16) transition of a CO2 laser, provides a novel method for generating high-power, picosecond, mid-IR laser pulses at a high repetition rate. By using 165 and 882 GHz beat-waves we show that cascaded phase-mismatched difference frequency generation plays a significant role in the four-wave mixing process in GaAs.

physics.optics↗