- 标题
- 摘要
- 关键词
- 实验方案
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Phase Conjugation and Mode Conversion in Stimulated Parametric Down-Conversion with Orbital Angular Momentum: a Geometrical Interpretation
摘要： We report on an experiment that investigates the spatial mode conversion in the process of parametric down-conversion seeded by a light beam in a superposition of orbital angular momentum modes. This process is interpreted in terms of a geometric representation of first-order spatial modes in a Poincaré sphere, providing an intuitive image of the phase conjugation and the topological charge conservation. We also make a comparison with the analogous phenomenon for optical parametric oscillators.
关键词： Orbital angular momentum,Parametric down-conversion,Optics,Phase conjugation
更新于2025-09-23 15:23:52
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Autofocusing with out-of-band phase conjugation
摘要： Electromagnetic phase conjugation provides an appealing path towards communication and target localization in dynamic media such as the Earth’s atmosphere. However, realizing phase conjugation-based devices has proven difficult because of the inherent complexity of systems that employ receivers and transmitters working on the same band. In this letter we propose the concept of out-of-band phase conjugation in which the frequency of the phase conjugated wave is an integer multiple of the incident wave frequency. Remarkably, the out-of-band phase conjugated wave maintains the autofocusing property that makes phase conjugation so powerful and opens the door to imaging technology effective in random and dynamic media.
关键词： Phase Conjugation,Retrodirective Arrays,Metasurface,Active Metamaterial,Time Reversal
更新于2025-09-23 15:21:21
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Negative Refraction in Time-Varying Strongly Coupled Plasmonic-Antennaa??Epsilon-Near-Zero Systems
摘要： Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply subwavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ～30%. Optical pumping at frequency ω induces a nonlinear polarization oscillating at 2ω responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than 4 orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale.
关键词： time-varying metasurfaces,epsilon-near-zero,plasmonic nano-antennas,negative refraction,phase conjugation
更新于2025-09-19 17:13:59
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Nd <sup>3+</sup> :YAG laser based on the <sup>4</sup> F <sub/>3/2</sub> → <sup>4</sup> I <sub/>13/2</sub> secondary transition with a phase-conjugate electro-optically Q-switched open multiloop cavity
摘要： Lasing on the 4F3/2 → 4I13/2 secondary transition (λ = 1.34 μm) in a Nd3+ : YAG laser with phase conjugation by four-wave mixing directly in the active laser medium was experimentally studied in the regime of electro-optic Q-switching of an open multiloop cavity. The use of an electro-optic Q-switch with a controllable delay of its opening made it possible to increase the amplitude and temporal stabilities of the output laser parameters. The maximum laser pulse energy was 100 mJ at a pulse duration of 120 ns. The phase-conjugate radiation divergence was 0.8 mrad at beam quality Mx2 = My2 = 1.3. Nonlinear optical conversion of 1.34 μm laser radiation to visible radiation was achieved experimentally. Second and third harmonic generation at wavelengths of 0.67 and 0.446 μm with conversion efficiencies of 25 % and 8 %, respectively, was demonstrated.
关键词： phase conjugation,secondary transition,stability of laser parameters,Nd3+ : YAG laser,electro-optic Q-switching
更新于2025-09-12 10:27:22
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An Efficient DFG Induced Wavelength Exchanged-OPC Using Only Two Ti:PPLN Waveguides with Single Pump Configuration
摘要： An unconventional single pump configuration of Wavelength Exchanged Optical Phase Conjugation (WE-OPC) through Difference Frequency Generation (DFG) employing two identical Ti:PPLN waveguides having same grating period and a single pump source is theoretically analyzed and simulated resulting in higher conversion efficiency of OPC.WE-OPC has been found very effective in extenuating nonlinearity and inflating spectral efficiency in optical transmission systems. The proposed WE-OPC enabled WDM optical transmission system modeled as a wavelength converter has been simulated with 10 channels offering much higher conversion efficiencies of about 3.3 dB and 3.49 dB for higher frequency band to lower frequency band and vice versa respectively.
关键词： Fiber optics communications,Dispersion compensation devices,Fiber optics and optical communications,Optical Phase conjugation,Wavelength conversion devices
更新于2025-09-12 10:27:22
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Nonlinearity Compensation through Optical Phase Conjugation for Improved Transmission Reach/Rate
摘要： Optical phase conjugation is a well-known technique to provide dispersion and nonlinearity compensation directly in the optical domain. The link properties play an important role in the achievable improvements in transmission reach/rate. Here, we review our recent investigations on the impact of sub-optimum transmission links as well as our effort on the implementation of the optical phase conjugator itself looking beyond using highly nonlinear fibers as nonlinear medium and focusing on integrated silicon waveguides. Preliminary results on combining optical phase conjugation with digital techniques such as probabilistic shaping will also be discussed.
关键词： optical phase conjugation,nonlinearity compensation,four-wave mixing,optical communication
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Portland, OR, USA (2018.11.13-2018.11.14)] 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Analog Photonic Timing Equalization Method for Multi-Channel RF Photonic Links
摘要： A new photonic timing equalization approach is presented to compensate the group delay among multiple signals in an analog photonic link. The results show the group delay variation across multiple RF photonic channels can be significantly compensated with 96.2% reduction after the equalization.
关键词： Phase conjugation,Analog photonic link,Arrayed waveguide grating(AWG),Group delay
更新于2025-09-09 09:28:46