ORCID

https://orcid.org/0009-0001-9737-3633

Keywords

holmium, chirped pulse amplifier, quasi-four-level, quasi-three-level, mid-infrared, optical parametric chirped pulse amplifier

Abstract

Broadband few-cycle high-power sources based on optical parametric amplifiers (OPA) in the mid-infrared (mid-IR) region are of great interest in a variety of applications such as spectroscopy, remote chemical sensing, medical procedures, and attosecond science. Among all the mid-IR nonlinear crystals for parametric amplification, zinc germanium phosphide (ZGP) has received significant attention due to its high nonlinear coefficient, high thermal conductivity, and high damage threshold, making it suitable for generating high average powers in the 3 – 12 µm range. A ZGP OPA requires a pump source above 2 µm due to a sharp increase in absorption immediately below 2 µm. This work’s focus was on the development of a 2.05 µm sub-10-picosecond source at high repetition rates for pumping a 3 – 5 µm ZGP optical parametric chirped pulse amplifier (OPCPA).

The work presented in this dissertation is a chirped pulse amplifier (CPA) based on holmium-doped yttrium lithium fluoride (Ho:YLF) in a two-stage double-pass configuration capable of producing 6-mJ pulse energies at 2.05-µm wavelength, 9-picosecond pulse duration and 5-kHz repetition rate. Extreme-cold temperatures of -45 °C were used improve the gain in Ho:YLF’s quasi-four-level system. These temperatures were reached with a standard air-cooled refrigeration system using ethanol as the circulating coolant, which enables operation at atmospheric pressure and eliminates the complexities, footprint, and costs associated with cryogenic cooling systems.

Notably, a two-channel OPA was developed for this work which produces the narrowband 2 µm seed for the Ho:YLF CPA and the 3 – 5 µm seed for the ZGP OPCPA in parallel. This enables future work on building a 3 – 5 µm broadband OPCPA producing few-cycle, few-mJ, carrier envelope phase (CEP)-stable pulses for the generation of attosecond X-ray pulses via high harmonic generation to be used in transient absorption spectroscopy experiments beyond the water window (>530 eV).

Completion Date

2024

Semester

Fall

Committee Chair

Zenghu Chang

Degree

Doctor of Philosophy (Ph.D.)

College

College of Optics and Photonics

Department

CREOL

Format

PDF

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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