arXiv subjects

C. Martijn de Sterke

Publications and source records attributed to C. Martijn de Sterke.

At least 19 recordsLinked to original sources

arXiv2026

Inverse reconstruction of dissipative Kerr soliton interactions

We reconstruct the pairwise interaction potential between dissipative Kerr solitons from the linear stability spectrum of a perfect soliton crystal solution of the Lugiato--Lefever equation. The solitons form an overdamped lattice whose positional eigenvalues encode the pairwise-force derivative, mirroring the extraction of microscopic interactions from phonon or relaxation spectra in condensed-matter systems. The method extends beyond quadratic dispersion and assumes no functional form for the interaction. Our theory predicts a novel state -the soft soliton crystal- which has vanishing stiffness and a diverging positional relaxation time, and also explains experimentally observed soliton steps as arising from a sign reversal of the pairwise-force derivative.

physics.optics↗

arXiv2026

Nonlinear Reshaping of Gaussian Water Wave Packets

The propagation of narrowband wave packets is a classical problem with broad relevance across nonlinear wave physics. Within the framework of the nonlinear Schrödinger equation, solitons are known to propagate without changing shape, whereas Gaussian envelopes may undergo substantial reshaping depending on the balance between dispersion and nonlinearity. Here, we combine laboratory experiments with numerical simulations to systematically investigate the evolution of hydrodynamic Gaussian wave packets over a wide range of amplitudes and spectral bandwidths. We show that when the envelope amplitude and width match those of the stationary NLSE soliton solution, the wave packet propagates steadily in the wave flume. More generally, by varying the amplitude of the Gaussian envelope, the wave packet may undergo either dispersive broadening or nonlinear focusing, resembling the dynamics of Satsuma-Yajima breathers. These findings may facilitate the controlled generation and manipulation of localized wave packets in a variety of nonlinear dispersive systems, including optics, plasmas, and Bose-Einstein condensates.

nlin.PS↗

arXiv2026

Asymptotic stability of laser-driven lightsails: Enhancement by optical dispersion engineering in gratings

Lightsails are promising spacecraft that can traverse interstellar distances within decades via radiation-pressure propulsion from high-power lasers. The envisioned missions crucially rely on the sail being confined within the propelling laser beam, requiring restoring and damping mechanisms for both translational and rotational degrees of freedom. Here, we use a two-dimensional rigid model to show that full asymptotic stability of planar nanophotonic sails can be achieved through purely optical, relativistic forces and torques, which damp all unstable degrees of freedom. By judiciously optimizing the angular and frequency dispersion of diffraction gratings, we find that damping can be substantially enhanced compared to plane-mirror sails. Over the full operating band for $0.2c$ missions it is several times larger, while over narrow wavelength bands, the enhancement is by three orders of magnitude. Therefore, relativistic effects can, in principle, provide comprehensive and realistic control over lightsail motion.

physics.optics↗

arXiv2026

Soliton crystal formation in Kerr cavities with an avoided mode crossing: a theoretical study

We theoretically and numerically investigate the formation of soliton crystals in Kerr microresonators in the presence of an avoided mode crossing (AMX). Our study combines dynamical simulations based on a modified Lugiato-Lefever equation (LLE) with a stability analysis of its stationary solutions. We show that, depending on its strength and spectral position, the AMX can either stabilize otherwise unstable soliton crystals or induce Turing patterns which subsequently seeds soliton crystal formation. Both perfect and imperfect soliton crystals can form below the pump threshold for spatiotemporal chaos, and we identify the conditions required for perfect crystals. Finally, we investigate modulation instability in the presence of an AMX, showing that it modifies the parametric gain and can suppress or promote Turing pattern formation depending on its spectral position.

physics.optics↗

arXiv2026

Radiation-pressure-induced non-Hermitian skin effect in elastic membranes

We show that optical forces perpendicular to the direction of the incident light, generated on structures with asymmetric optical scattering, can manipulate longitudinal elastic waves traveling in that same perpendicular direction. When the radiation pressure acts unidirectionally, reciprocity and hence Newton's Third Law are effectively broken. As a result, the waves grow exponentially with position, an instance of the non-Hermitian skin effect. The effect can be enhanced by orders of magnitude to measurable scales in optically dispersive nanostructured membranes. These findings are particularly relevant in the context of lightsails, spacecraft propelled by radiation pressure from high-power lasers. Our discovery showcases a new interaction between radiation pressure and elastic waves, which taps into the rich field of non-Hermitian physics.

physics.optics↗

arXiv2025

Photonic Lightsails: Fast and Stable Propulsion for Interstellar Travel

Lightsails are a highly promising spacecraft concept that has attracted interest in recent years due to its potential to travel at near-relativistic speeds. Such speeds, which current conventional crafts cannot reach, offer tantalizing opportunities to probe nearby stellar systems within a human lifetime. Recent advancements in photonics and metamaterials have created novel solutions to challenges in propulsion and stability facing lightsail missions. This review introduces the physical principles underpinning lightsail spacecrafts and discusses how photonics coupled with inverse design substantially enhance lightsail performance compared to plain reflectors. These developments pave the way through a previously inaccessible frontier of space exploration.

astro-ph.IM↗

arXiv2024

Theory of multicolor soliton microcombs

We present a general theory of multicolor soliton microcombs. These frequency combs require specially engineered dispersion and have an optical spectrum consisting of multiple spectral windows, centered at distinct frequencies. Our theory is based on a multiple-scale approach applied to the Lugiato-Lefever equation, and provides a framework to investigate different pumping configurations. For multi-frequency pumping, we predict a progressively lower pumping threshold as the number of spectral windows increases due to an enhancement of the effective nonlinear parameter. However, multi-frequency pumping is not a prerequisite for the formation of these combs and can emerge even with a single driving field. Our theoretical predictions are in excellent agreement with numerical simulations.

physics.optics↗

arXiv2024

Observation of fractional evolution in nonlinear optics

The idea of fractional derivatives has a long history that dates back centuries. Apart from their intriguing mathematical properties, fractional derivatives have been studied widely in physics, for example in quantum mechanics and generally in systems with nonlocal temporal or spatial interactions. However, systematic experiments have been rare due to challenges associated with the physical implementation. Here we report the observation and full characterization of a family of temporal optical solitons that are governed by a nonlinear wave equation with a fractional Laplacian. This equation has solutions with unique properties such as non-exponential tails and a very small time-bandwidth product.

physics.optics↗

arXiv2024

All-optical damping forces enhanced by metasurfaces for stable relativistic lightsail propulsion

Lightsails are a promising spacecraft concept that can reach relativistic speeds via propulsion by laser light, allowing travel to nearby stars within a human lifetime. The success of a lightsail mission requires that any motion in the plane transverse to the propagation direction is bounded and damped for the entire acceleration phase. Here, we demonstrate that a previously unappreciated relativistic force, which generalizes the Poynting-Robertson effect, can passively damp this transverse motion. We show that this purely optical effect can be enhanced by two orders of magnitude compared to plane mirror sails by judicious design of the scattering response. We thus demonstrate that exploiting relativistic effects may be a practical means to control the motion of lightsails.

physics.app-ph↗

arXiv2023

Broadband terahertz near-field excitation and detection of silicon photonic crystal modes

Chip-based terahertz (THz) devices are emerging as versatile tools for manipulating mm-wave frequencies in the context of integrated high-speed communication technologies for potential sixth-generation (6G) wireless applications. The characterization of THz devices is typically performed using far-field techniques that provide limited information about the underlying physical mechanisms producing them. As the library of chip-based functionalities expands, e.g., for tailoring the emission and directional propagation properties of THz antennas and waveguides, novel characterization techniques will likely be beneficial for observing subtle effects that are sensitive to a device's structural parameters. Here we present near-field measurements showing the emission properties of a broadband THz emitter placed in the vicinity of a photonic crystal (PHC) slab. These experiments reveal long-predicted emission properties, but which to our knowledge have yet to be experimentally observed at THz frequencies. We demonstrate three distinct effects between 0.3-0.5 THz: (i) field suppression at frequencies corresponding to quasi-TE bandgaps (ii) a frequency-dependent directed emission along two distinct pathways for two neighboring frequencies, resulting in a local field concentration; (iii) a re-direction of the emission, achieved by rotating the PHC with respect to the dipole orientation. Simulations reveal that the observed behavior can be predicted from the underlying band structure. Our results highlight the opportunities that PHCs can potentially provide for alignment-free, chip-based 6G technologies. Our experimental technique extends the applicability realms of THz spectroscopy and will find use for characterizing the THz modes supported by true samples, whose inherent imperfections cannot realistically be accounted for by simulations, particularly in highly dispersive frequency bands.

physics.optics↗

arXiv2022

Solitons in media with mixed, high-order dispersion and cubic nonlinearity

Although most soliton research has traditionally considered dominant quadratic dispersion, the recent discovery of pure-quartic solitons has inspired analysis of soliton solutions with large higher orders of dispersion. Here we present analytic expressions for families of bright soliton solutions at arbitrary dispersion orders and practical methods to obtain the associated dispersion relations. These results provide a framework for considering higher order dispersion solitons and show the potential for further investigation of solitons in higher order dispersion systems.

nlin.PS↗

arXiv2021

Dark solitons under higher order dispersion

We show theoretically that dark solitons can exist in the presence of pure quartic dispersion, and also in the presence of both quadratic and quartic dispersive effects, displaying a much greater variety of possible solutions and dynamics than for pure quadratic dispersion. The interplay of the two dispersion orders may lead to oscillatory non-vanishing tails, which enables the possibility of bound, potentially stable, multi-soliton states. Dark soliton-like states which connect to low amplitude oscillations are also shown to be possible. Dynamical evolution results corroborate the stability picture obtained, and possible avenues for dark soliton generation are explored.

nlin.PS↗

arXiv2021

Self-stabilization of light sails by damped internal degrees of freedom

We consider the motion of a light sail that is accelerated by a powerful laser beam. We derive the equations of motion for two proof-of-concept sail designs with damped internal degrees of freedom. Using linear stability analysis we show that perturbations of the sail movement in all lateral degrees of freedom can be damped passively. This analysis also shows complicated behaviour akin to that associated with exceptional points in PT-symmetric systems in optics and quantum mechanics. The excess heat that is produced by the damping mechanism is likely to be substantially smaller than the expected heating due to the partial absorption of the incident laser beam by the sail.

physics.class-ph↗

arXiv2020

The interaction of Kerr nonlinearity with even-orders of dispersion: an infinite hierarchy of solitons

Temporal solitons are optical pulses that arise from the balance of negative group-velocity dispersion and self-phase modulation. For decades only quadratic dispersion was considered, with higher order dispersion thought of as a nuisance. Following the recent reporting of pure-quartic solitons, we here provide experimental and numerical evidence for an infinite hierarchy of solitons that balance self-phase modulation and arbitrary negative pure, even-order dispersion. Specifically, we experimentally demonstrate the existence of solitons with pure-sextic ($β_6$), -octic ($β_8$) and -decic ($β_{10}$) dispersion, limited only by the performance of our components, and show numerical evidence for the existence of solitons involving pure $16^{\rm th}$ order dispersion. Phase-resolved temporal and spectral characterization reveals that these pulses, exhibit increasing spectral flatness with dispersion order. The measured energy-width scaling laws suggest dramatic advantages for ultrashort pulses. These results broaden the fundamental understanding of solitons and present new avenues to engineer ultrafast pulses in nonlinear optics and its applications.

physics.optics↗

arXiv2020

Omnidirectional field enhancements drive giant nonlinearities in epsilon-near-zero waveguides

Bulk materials possessing a relative electric permittivity $\varepsilon$ close to zero exhibit giant Kerr nonlinearities. However, harnessing this response in guided-wave geometries is not straightforward, due to the extreme and counter-intuitive properties of epsilon-near-zero materials. Here we investigate, through rigorous calculations of the Kerr nonlinear coefficient, how the remarkable nonlinear properties of such materials can be exploited in several different types of structures, including bulk films, plasmonic nanowires, and metal nanoapertures. We find the largest Kerr nonlinear response when both the modal area and the group velocity are simultaneously minimized, corresponding to omnidirectional field enhancement. The physical insights developed will be key for understanding and engineering nonlinear nanophotonic systems with extreme nonlinearities and point to new design paradigms.

physics.optics↗

arXiv2020

Polychromatic soliton molecules

Soliton molecules, bound states composed of interacting fundamental solitons, exhibit remarkable resemblance with chemical compounds and phenomena in quantum mechanics. Whereas optical molecules composed of two or more temporally locked solitons have been observed in a variety of platforms, soliton molecules formed by bound solitons at different frequencies have only recently been theoretically proposed. Here, we report the observation of polychromatic soliton molecules within a mode-locked laser cavity, achieving the desired dispersion by implementing a spectral pulse-shaper. This system supports two or more coincident solitons with different frequencies, but common group velocities. Our results open new directions of exploration in nonlinear dynamics within systems with complex dispersion and offer a convenient platform for optical analogies to mutual trapping and spectral tunneling in quantum mechanics.

physics.optics↗

arXiv2019

The pure-quartic soliton laser

The generation of ultrashort pulses hinges on the careful management of dispersion. Traditionally, this has exclusively involved second-order dispersion, while higher-order dispersion was treated as a nuisance to be minimized. Here we show that high-order dispersion can be strategically leveraged to access an uncharted regime of ultrafast laser operation. In particular, we demonstrate a mode-locked laser, with an intra-cavity spectral pulse-shaper, that emits pure-quartic soliton pulses, which arise from the interaction of the fourth-order dispersion and the Kerr nonlinearity. Using phase-resolved measurements we demonstrate that the energy of these pulses is proportional to the third power of the inverse pulse duration. This implies a dramatic increase in the energy of ultrashort pulses compared to those emitted by soliton lasers to date. These results not only demonstrate a novel approach to ultrafast lasers, but more fundamentally, they clarify the use of higher-order dispersion for optical pulse control, opening up a plethora of possibilities in nonlinear optics and its applications.

physics.optics↗

arXiv2019

Modular Hybrid Plasmonic Integrated Circuit -- Rotation, Nanofocusing and Nonlinear Enhancement

We introduce a modular approach for efficiently interfacing photonic integrated circuits with deep-sub-wavelength hybrid plasmonic functionality. We demonstrate that an off-the-shelf silicon-on-insulator waveguide can be post-processed into an integrated hybrid plasmonic circuit by evaporating a silica and gold nanolayer. The circuit consists of a plasmonic rotator and a nanofocusser module, which together result in nano-scale, nonlinear wavelength conversion. We experimentally characterize each module, and demonstrate an intensity enhancement of $>200$ in a calculated mode area of $50\,{\rm nm}^2$ at $λ= 1320\,{\rm nm}$ using second harmonic generation. This work opens the door to customized plasmonic functionalities on industry-standard waveguides, bridging conventional integrated photonic circuits with hybrid plasmonic devices. This approach promises convenient access to nanometre-scale quantum information processing, nonlinear plasmonics, and single-molecule sensing.

physics.optics↗