arXiv subjects

Charles Durfee

Publications and source records attributed to Charles Durfee.

4 recordsLinked to original sources

arXiv2025

Phase matching in Vector Beam Driven High Harmonic Generation with 3D-printed Gas Cells

We present experimental results of high harmonic generation(HHG) driven by a 1300 nm beam in three different polarization states: linear, radial, and azimuthal. We found that the optimal pressure for phasematching was roughly twice as high for the vector beam drivers than the linear driver. We attribute this difference in pressure primarily to the Gouy phase, which differs by a factor of two between the linear and vector polarization states. We demonstrate a target for HHG that produces a uniform pressure profile in the interaction region that is nearly identical to the backing pressure, and preserves the mode of the driving beam. We provide characterization and validation of this technique through flow simulations and experimental measurements.

physics.optics↗

arXiv2024

Nonlinear Shaping in the Picosecond Gap

Lightwave pulse shaping in the picosecond regime has remained unaddressed because it resides beyond the limits of state-of-the-art techniques, either due to its inherently narrow spectral content or fundamental speed limitations in electronic devices. The so-called picosecond shaping gap hampers progress in all areas correlated with time-modulated light-matter interactions, such as photoelectronics, health and medical technologies, and energy and material sciences. We report on a novel nonlinear method to simultaneously frequency-convert and adaptably shape the envelope of light wavepackets in the picosecond regime by balancing spectral engineering and nonlinear conversion in solid-state nonlinear media, without requiring active devices. We capture computationally the versatility of this methodology across a diverse set of nonlinear conversion chains and initial conditions. We also provide experimental evidence of this framework producing picosecond-shaped, ultra-narrowband, near-transform limited light pulses from broadband, femtosecond input pulses, paving the way toward programmable lightwave shaping at GHz-to-THz frequencies.

physics.optics↗

arXiv2020

Temporal shaping of narrow-band picosecond pulses via non-colinear sum-frequency mixing of dispersion-controlled pulses

A long sought-after goal for photocathode electron sources has been to improve performance by temporally shaping the incident exitation laser pulse. The narrow bandwidth, short wavelength, and picosecond pulse duration make it challenging to employ conventional spectral pulse shaping techniques. We present a novel and efficient intensity-envelope shaping technique achieved during nonlinear upconversion through opposite-chirp sum-frequency mixing. We also present a numerical case-study of the LCLS-II photoinjector where transverse electron emittance is improved by at least 25%.

physics.optics↗

arXiv2020

Wavelength-multiplexed single-shot ptychography

Diagnostics capable of interrogating dynamics in harsh environments such as plasma have remained essentially unchanged in recent decades. Developments in advanced microscopy techniques will improve our understanding of the physics involved in these events. Recently developed single-shot ptychography (SSP) provides a pathway towards sophisticated plasma metrologies. Here we introduce wavelength-multiplexed single-shot ptychography (WM-SSP), which allows for hyperspectral, spatially and temporally resolved phase and amplitude contrast imaging. Furthermore, we introduce a novel probe constraint common to all wavelength multiplexed modalities in the single-shot geometry and present modifications to SSP that improve reconstruction fidelity and robustness. WM-SSP was experimentally realized and simulations show the technique's ability to deconvolve the electron and neutral densities within the plasma. WM-SSP will pave the way to a new generation of quantitative plasma imaging techniques.

physics.optics↗