Development of Mid-Infrared Lasers for Soft X-Ray High Harmonic Generation
Drew Morrill, University of Colorado Boulder
High harmonic generation (HHG) is an extremely nonlinear optical process in which wavelengths are converted from the micron scale (~1 eV) down to the scale of 10s of or even single nanometers (~1000 eV). HHG is a finely balanced process with exacting demands on the laser system. In this talk, I will describe my team’s work in the field of laser physics as we design and construct a novel laser source that will enable the generation of coherent, soft X-ray light in a stable, table-top scale format. The home-built laser system is a 1 kHz optical parametric chirped pulse amplifier (OPCPA). The system is comprised of a number of components. I will discuss a stable, all-fiber front end, which employs a highly nonlinear fiber to provide synchronized seed pulses at both 1.5 micron (Erbium wavelengths) and 1 micron (Ytterbium wavelengths). The 1 micron pulses are amplified to about 15 mJ in a cryogenically cooled Yb:YAG regenerative amplifier and provide the pump for the OPCPA. The 1.5 micron (signal) pulses are stretched and given spectral and amplitude modulation using a pulse shaper. The signal and pump are mixed in a series of four periodically poled lithium niobate (PPLN) crystals, resulting in several hundred microjoules of pulse energy at 3.1 microns with a flat spectral phase. Simultaneously, we are developing a capillary based HHG source, which is made suitable for a mid-infrared driving laser through the use of an anti-resonant hollow core fiber. Finally, I will discuss my practicum work at Lawrence Livermore National Laboratory in the area of power scaling of fiber laser amplifiers.
Abstract Author(s): Drew Morrill, Dan Carlson, Will Hettel, Michaël Hemmer, Margaret Murnane, Henry Kapteyn