Objective

In the most recent decadal laser technology report prepared for the US government by the scientific community, the development of intense, tunable high-average power mid-infrared lasers was identified as a critical need for near term scientific advancements. Future applications of this optical instrument could include materials processing, telecommunications, nonlinear optics, defense applications and more. To answer this call, the James R. McDonald lab is planning to develop a 1.3-4.2 µm laser source, based on optical parametric amplification driven by JRML's newest laser system producing 1030 nm, 3.2 mJ, 450 fs laser pulses at 100 kHz repetition rate. In this project, we successfully conducted and benchmarked the key stages of the proposed mid-infrared source, namely the white light continuum generation module and the single pass difference frequency generation amplifier. We demonstrated supercontinuum generation in a 20 mm YAG crystal spanning over 2 octaves (400-2500 nm) and a 1000x amplification via DFG in a KTA crystal which supports ~250 fs mid-infrared pulses. Our work indicates that, when completed, JRML's mid-infrared source will exceed 50 W of average power.

Optical Parametric Amplifier (OPA)

Also called difference frequency generation, an OPA is an optical instrument that uses nonlinear crystals to create a source beam with a tunable wavelength. This process consists of sending a pump beam through a beam splitter which takes 10% of the light source and directs it into a YAG (Yttrium Aluminum Garnet) crystal, resulting in a phenomenon called white light generation (WLG), which expands the original bandwidth and the spectrum of colors developed is known as the signal beam. Ultimately, the initial pump beam propagates a different path and meets the signal beam at the KTA (Potassium Titanyl Arsenate) crystal that is oriented such that the pump beam is depleted and the signal beam is amplified upon exiting the crystal. In effect, an idler beam emerges with the capability of modifying the wavelength to a specified parameter based on the users' preference.

Fig. 1. White Light Continuum Generation results from testing different nonlinear crystals (Spectrum vs. Wavelength graph)

Fig. 2. OPA output signals (Signal and Idler beams, respectively)

Fig. 3. Pulse energy and Pulse duration as a function of wavelength

Acknowledgements

Special thank you to Cosmin Blaga and the team (Sajed Hosseini, Pavan Muddukrishna, Eric Mullins, Frank Genty & Koby Harding) working in our AMO department at Kansas State University. I would like to acknowledge and thank the KSU staff responsible for the program (Kim Coy, Loren Greenman, and Bret Flanders), as well as the other undergraduate researchers.

This material is based upon work supported by the National Science Foundation under Grant No. 2244539. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Final Presentation