Low-Cost System Generates Intense, Ultrafast Long-Wavelength Mid-Infrared Laser Pulses

Abstract

The University of Central Florida invention is a low-cost laser system that can achieve intense (1–10 GW) to super-intense (10 GW-1 TW) peak power pulses in the difficult-to-achieve long-wavelength (?>5 µm) mid-IR (MIR) spectral range. With such capabilities, the UCF Coherent Subharmonic Optical Parametric Amplifier (CSOPA) system enables new areas, including attosecond science and tabletop laser-driven particle accelerators for medical applications, including physical therapy.

Existing techniques for generating intense, ultrafast long-wavelength MIR pulses typically offer a conversion efficiency from near-IR to MIR of less than 1 percent. The techniques also require large, complicated laser facilities. Though another method provides high conversion efficiency, broad bandwidth, and preserves the coherence of the MIR output pulses, it delivers only low-energy pulses (1-10 nJ). The UCF invention offers a solution to all these issues.

Technical Details
The UCF invention is a coherent subharmonic optical parametric amplifier (CSOPA) laser system and method. The CSOPA uses a single intense input pump pulse, one or more passes through a nonlinear crystal, and does not require a resonator. As a result, subharmonic MIR pulses of much higher peak power are achievable. The energy conversion efficiency from the first pulse to the subharmonic wavelengths may exceed 50 percent due to: 1) the total photon recycling and 2) the non-dissipative nature of parametric conversion. A CSOPA requires precise control of the relative phases of the first pulse and the subharmonic pulse, which is achievable using an adjustable time delay such as a piezoelectric actuator.

In some embodiments, the CSOPA includes one or more amplifiers to amplify at least some of the pump pulses before the beam combiner. Any number or types of amplifiers are usable in the configuration, such as a chirped pulse amplifier (CPA), an optical parametric amplifier (OPA), or an optical parametric chirped-pulse amplifier (OPCPA). Also, the CSOPA may include multiple amplification stages. For instance, the CSOPA may consist of one or more pre-amplifiers and one or more main-stage or power amplifiers.

In one example application, the laser source includes a carrier envelope phase (CEP)-stabilized femtosecond laser amplifier providing phase-stabilized femtosecond input pulses with relatively high pulse energies (1-10 mJ or greater). The frequency divider is a sub-harmonic optical parametric generation (OPG) crystal.

Partnering Opportunity
The research team is looking for partners to develop the technology further for commercialization.

Benefit

Market Application

Publications

Ultra-broadband mid-infrared frequency combs produced by optical subharmonic generation, Quantum Electronics Volume 52, Number 4, 307-312 (2022).