Thermalization of Light’s Orbital Angular Momentum in Nonlinear Multimode Waveguide Systems

Wu, Fan O.; Zhong, Qi; Ren, Hengxin; Jung, Paweł S.; Makris, Konstantinos G.; Christodoulides, Demetrios N.

doi:10.1103/physrevlett.128.123901

Cited by 20 publications

(6 citation statements)

References 51 publications

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“…As in the case of standard statistical mechanics 39 , the entropy of the optical multimode arrangement can be built within a microcanonical ensemble formalism by accounting all possible microstates, each containing information as to the energy/power and phase distribution among all modes in the system. In defining the macrostates, the energy/power distribution is retained while the phase information is omitted 40 (being superfluous given that it is uniformly distributed within the range 0 to 2 π ). In this respect, the nonlinear interaction acts merely as an agent that enables a chaotic reshuffling of optical energy among modes and therefore facilitates thermalization.…”

Section: Resultsmentioning

confidence: 99%

Universality of light thermalization in multimoded nonlinear optical systems

Zhong

Hassan

et al. 2023

Nat Commun

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Recent experimental studies in heavily multimoded nonlinear optical systems have demonstrated that the optical power evolves towards a Rayleigh–Jeans (RJ) equilibrium state. To interpret these results, the notion of wave turbulence founded on four-wave mixing models has been invoked. Quite recently, a different paradigm for dealing with this class of problems has emerged based on thermodynamic principles. In this formalism, the RJ distribution arises solely because of ergodicity. This suggests that the RJ distribution has a more general origin than was earlier thought. Here, we verify this universality hypothesis by investigating various nonlinear light-matter coupling effects in physically accessible multimode platforms. In all cases, we find that the system evolves towards a RJ equilibrium—even when the wave-mixing paradigm completely fails. These observations, not only support a thermodynamic/probabilistic interpretation of these results, but also provide the foundations to expand this thermodynamic formalism along other major disciplines in physics.

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Section: Resultsmentioning

confidence: 99%

Universality of light thermalization in multimoded nonlinear optical systems

Zhong

Hassan

et al. 2023

Nat Commun

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“…15 In the thermodynamic framework, this ensures that modes associated with opposite topological charges have the same occupancy at thermal equilibrium. 16,17 At the fiber output, the beam was collimated, and its SOP was characterized by means of a standard polarimetric setup. All the optical components of the latter work within a narrow spectral band.…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

Spatial beam self-cleaning in multimode fibers: the role of light polarization

Ferraro

Mangini

Jauberteau

et al. 2023

Laser Resonators, Microresonators, and Beam Control XXV

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Since its first demonstration, spatial beam self-cleaning has been targeted as a breakthrough nonlinear effect, for its potential of extending to multimode fibers different technologies based on single-mode fibers, such as fiber lasers and endoscopes. To date, most of the theoretical descriptions of beam self-cleaning are based on scalar models. Whereas, in experiments the analysis of the polarization state of self-cleaned beams is often neglected. Here, we fill this gap between theory and experiments, by demonstrating that a self-cleaned beam eventually loses its degree of polarization, as long as linearly polarized light of enough power is injected at the fiber input. Our results are cast in the framework of a thermodynamic description of nonlinear beam propagation in multimode fibers, providing the first experimental proof of the applicability of scalar theories for the description of the spatial beam self-cleaning effect.

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“…The abundance of potential waveguide architectures now available opens doors to exploring an extremely rich variety of propagation dynamics [1,2]. Solitons [3][4][5][6][7][8] and associated resonant radiations through geometric parametric instabilities [9], invariant space-time wavepackets [10][11][12][13][14], self-cleaning [15,16] and related condensation/thermalization [17][18][19][20][21][22] phenomena are some nonlinear fascinating effects, among others, taking place in multimode fibers that have been intensively studied during the last few years. Beside these nonlinear phenomena, the use of multimode fibers for increasing the number of data-transmitting channels lets envision the possibility to overcome the expected data-carrying capacity crunch of single-mode fibers.…”

Section: Introductionmentioning

confidence: 99%

Efficient multimode vectorial nonlinear propagation solver beyond the weak guidance approximation

Béjot

2024

J. Opt. Soc. Am. B

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In this paper, we present an efficient numerical model able to solve the vectorial nonlinear pulse propagation equation in circularly symmetric multimode waveguides. The algorithm takes advantage of the conservation of total angular momentum of light upon propagation and takes into account the vectorial nature of the propagating modes, making it particularly relevant for studies in ring-core fibers. While conventional propagation solvers exhibit a computational complexity scaling as Nmode4, where Nmode is the number of considered modes, the present solver scales as Nmode3/2. As a first example, it is shown that orbital angular momentum modulation instability processes take place in ring-core fibers in realistic conditions. Finally, it is predicted that the modulation instability process is followed by the appearance of breather-like angular structures.

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Thermalization of Light’s Orbital Angular Momentum in Nonlinear Multimode Waveguide Systems

Cited by 20 publications

References 51 publications

Universality of light thermalization in multimoded nonlinear optical systems

Universality of light thermalization in multimoded nonlinear optical systems

Spatial beam self-cleaning in multimode fibers: the role of light polarization

Efficient multimode vectorial nonlinear propagation solver beyond the weak guidance approximation

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