• Chinese Optics Letters
  • Vol. 20, Issue 11, 113801 (2022)
Ding Yan, Zhiyuan Zhong, Tong Qi, Hongying Chen, and Wei Gao*
Author Affiliations
  • Heilongjiang Provincial Key Laboratory of Quantum Control, School of Measurement and Communication Engineering, Harbin University of Science and Technology, Harbin 150080, China
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    DOI: 10.3788/COL202220.113801 Cite this Article
    Ding Yan, Zhiyuan Zhong, Tong Qi, Hongying Chen, Wei Gao. High-fidelity parametric amplification of Ince–Gaussian beams[J]. Chinese Optics Letters, 2022, 20(11): 113801 Copy Citation Text show less

    Abstract

    Ince–Gaussian (IG) beams, as eigenfunctions of the paraxial wave equation in elliptical coordinates, are attracting increasing interest owing to their propagation-invariant and full-field properties. Optical amplification via parametric interactions can further expand their application areas, yet it is rarely studied. In this work, we report on a high-fidelity parametric amplifier for IG beams. The nonlinear transformation of the spatial spectra of the signal and associated influences on the beam profiles of the amplified signal, under different pump structures, were theoretically and experimentally investigated. By using a perfect flattop beam as the pump, we show that the transverse structure of IG signals is well maintained, and the distortion induced by radial-mode degeneration is overcome during amplification. This proof-of-principle demonstration paves the way for a mode-independent and distortion-free amplifier of arbitrary structured light and has great significance in relevant areas, such as quantum optics, tunable infrared-laser generation, and image amplification.

    1. Introduction

    Soon after Franken et al. observed second-harmonic generation[1], Kingston et al. proposed an optical parametric oscillator in 1962[2,3], and then Wang and Racetle first, to the best of our knowledge, observed parametric gain of the laser in NH4H2PO4 (ADP) crystals in 1965[4]. Subsequent research and further development of optical parametric amplification (OPA) have received significant attention due to its ability to amplify weak signals with high and ultra-broadband gain, meanwhile, generating the difference frequency light (i.e., idler beam). This technique has been applied in various areas such as strong-field physics, tunable infrared-laser generation, and noiseless image amplification[59]. The emergence of structured light represented by beams carrying orbital angular momentum (OAM) renewed broad research interest[1014]. Beyond the OAM, structured light, in principle, can be extended to all degrees of freedom and dimensions, which has revived many areas ranging from classical to quantum light and fundamental physics to advanced photonic techniques[1519]. Structured light can typically be generated by low-peak-power devices such as liquid-crystal spatial light modulators (SLMs)[20], digital micromirror devices[2123], q-plates[24], and other spin-orbit approaches[2527]. The need for structured light demonstrations at higher powers for industrial applications has remained an open challenge[10]. OPA is an alternative method to obtain high-power structured light. The OPA of OAM-carrying beams and the transformation of OAM were studied both theoretically and experimentally[2830]. Polarization-insensitive OPA of radially polarized femtosecond pulses was also successfully achieved with high gain[31].

    Ding Yan, Zhiyuan Zhong, Tong Qi, Hongying Chen, Wei Gao. High-fidelity parametric amplification of Ince–Gaussian beams[J]. Chinese Optics Letters, 2022, 20(11): 113801
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