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1. Efficient parametric amplification via simultaneous second harmonic generation

   https://doi.org/10.1364/OE.437864  

   Flemens, Noah; Swenson, Nicolas; Moses, Jeffrey (September 2021, Optics Express)

   We introduce a concept for efficient optical parametric amplification (OPA) based on simultaneously phase-matched idler second harmonic generation (SHG), which together exhibits the dynamical behavior of parametric amplification but with damped conversion-back-conversion cycles. This enables amplification efficiency exceeding that of conventional OPA by several-fold for femtosecond and picosecond signal pulses with bell-shaped intensity profiles by allowing a near-uniform spatiotemporal depletion of the pump wave. We develop a Duffing oscillator model that unifies the description of conventional OPA and amplification accompanied by idler photon displacement by either linear absorption or SHG. A spatiotemporal analysis of devices based on birefringent or superlattice quasi-phase matching in common bulk media predicts energy conversion up to 55%. 

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2. Micromirror based optical phased array for wide-angle beamsteering

   https://doi.org/10.1109/MEMSYS.2017.7863553  

   Wang, Youmin; Wu, Ming C. (February 2017, Micro Electro Mechanical Systems (MEMS), 2017 IEEE 30th International Conference on)

   Optical phased array (OPA) is a key enabling element for solid state LIDAR (light detection and ranging). In this paper, we demonstrate a novel MEMS micromirror array OPA. Vertical combdrive actuators are integrated underneath the mirrors to achieve a small pitch (2.4μm) and a large field of view (22° at 905nm wavelength and 40° at 1550nm). The OPA has 2μs response time, and 10V actuation voltage. 

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3. Non-Hermitian Dynamics Mimicked by a Fully Parametric Hybrid Nonlinear Optical System

   https://doi.org/10.1364/NP.2020.NpM3E.2  

   Flemens, Noah; Moses, Jeffrey (January 2020, OSA Advanced Photonics Congress (AP) 2020 (IPR, NP, NOMA, Networks, PVLED, PSC, SPPCom, SOF))

   null (Ed.)

   We demonstrate that hybridization of OPA and idler SHG produces desirable nonlinear dynamics equivalent to OPA with idler loss, despite being a fully conservative system. Both systems take the form of a damped Duffing oscillator. 

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4. Calibration of optical parametric amplifiers for frequency-domain ultrafast coherent multidimensional spectroscopic studies

   https://doi.org/10.1063/5.0271282  

   Kain, Schuyler; Thompson, Blaise J; Kohler, Daniel D; Wright, John C (July 2025, Review of Scientific Instruments)

   Frequency-domain ultrafast coherent multidimensional spectroscopy has made possible a family of fully coherent spectroscopies that can create and interrogate characteristic superpositions of the quantum-mechanical states of a system under investigation. Typical applications include the resolution of couplings and dynamics among multiple electronic states in atoms, molecules, and materials. These methods require scanning the wavelengths of multiple, ultrafast light sources—often optical parametric amplifiers (OPAs). Spectral calibration of the OPA output (a.k.a. wavelength-tuning) involves optimizing the OPA output intensity by adjusting the angles of its component nonlinear crystals and motorized delay stages. When the spectral range addressed in the experiment is large, optimization and control of the one or more OPAs become complex. This work describes an automated calibration strategy that measures the multidimensional configuration-space of a typical 800-nm OPA over all angular and delay degrees-of-freedom in order to create a global tuning curve that spans its dynamic spectral range with optimal power and smooth interpolation. To accomplish this task, the optimization assesses the wavelength-dependent variations to the temporal and spatial characteristics of the OPA output caused by material dispersion so that compensations may be applied during a wavelength scan. 

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5. Liquid-crystal-based visible-light integrated optical phased arrays and application to underwater communications

   https://doi.org/10.1364/OL.494387  

   Notaros, Milica; DeSantis, Daniel_M; Raval, Manan; Notaros, Jelena (October 2023, Optics Letters)

   In this Letter, we present the first, to the best of our knowledge, liquid-crystal-based integrated optical phased arrays (OPAs) that enable visible-light beam forming and steering. A cascaded OPA architecture is developed and experimentally shown to emit a beam in the far field at a 632.8-nm wavelength with a power full width at half maximum of 0.4°×1.6° and 7.2° beam-steering range within ±3.4 V. Furthermore, we show the first visible-light integrated-OPA-based free-space-optical-communications transmitter and use it to demonstrate the first integrated-OPA-based underwater-wireless-optical-communications link. We experimentally demonstrate a 1-Gbps on–off-keying link through water and an electronically-switchable point-to-multipoint link with channel selectivity greater than 19 dB through a water-filled tank. 

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