A5049169851- Photonic and Optical Devices
- Metamaterials and Metasurfaces Applications
- Orbital Angular Momentum in Optics
- Mechanical and Optical Resonators
- Advanced Antenna and Metasurface Technologies
- Plasmonic and Surface Plasmon Research
- Advanced Fiber Laser Technologies
- Optical Coatings and Gratings
- Energy Harvesting in Wireless Networks
- Semiconductor Lasers and Optical Devices
- Photonic Crystals and Applications
- Antenna Design and Analysis
- Near-Field Optical Microscopy
- Advanced Fiber Optic Sensors
- Microfluidic and Bio-sensing Technologies
- Ethics and Social Impacts of AI
- Advanced Photonic Communication Systems
- Optical and Acousto-Optic Technologies
- Microwave Engineering and Waveguides
- Radio Wave Propagation Studies
- Random lasers and scattering media
- Radio Astronomy Observations and Technology
- Explainable Artificial Intelligence (XAI)
- Decision-Making and Behavioral Economics
- Model Reduction and Neural Networks
Harvard University
2016-2025
Vrije Universiteit Brussel
2016-2025
Harvard University Press
2020-2023
Institute of Applied Physics
2012-2018
Université de Yaoundé I
2017
FORTH Institute of Electronic Structure and Laser
2016
Vrije Universiteit Amsterdam
2010-2015
Our ability to generate new distributions of light has been remarkably enhanced in recent years. At the most fundamental level, these patterns are obtained by ingeniously combining different electromagnetic modes. Interestingly, modal superposition occurs spatial, temporal as well spatio-temporal domain. This generalized concept structured is being applied across entire spectrum optics: generating classical and quantum states light, harnessing linear nonlinear light-matter interactions,...
We demonstrate how the optical gradient force between two waveguides can be enhanced using transformation optics. A thin layer of double-negative or single-negative metamaterial shrink interwaveguide distance perceived by light, resulting in a more than tenfold enhancement force. This process is remarkably robust to dissipative loss normally observed metamaterials. Our results provide an alternative way boost forces nanophotonic actuation systems and may combined with existing...
In high energy physics, unknown particles are identified by determining their mass from the Cherenkov radiation cone that is emitted as they pass through detector apparatus. However, at higher particle momentum, angle of saturates to a value independent generating particle, making it difficult effectively distinguish between different particles. Here, we show how geometric formalism transformation optics can be applied describe in an arbitrary anisotropic medium. On basis these results,...
Transformation Optics asks Maxwell's equations what kind of electromagnetic medium recreate some smooth deformation space.The guiding principle is Einstein's covariance: that any physical theory must take the same form in coordinate system.This requirement fixes very precisely required medium.
Since its advent in the 1970s, optical tweezers have been widely deployed as a preferred non-contact technique for manipulating microscale objects. On-chip integrated tweezers, which afford significant size, weight, and cost benefits, implemented, relying upon near-field evanescent waves. As result, these are only capable of manipulation near-surface regions often demand high power since interactions relatively weak. We introduce on-chip based on freeform micro-optics, comprise reflectors or...
Electromagnetic energy harvesting, i.e., capturing from ambient microwave signals, may become an essential part in extending the battery lifetime of wearable devices. Here, we present a design harvester based on cut-wire metasurface with integrated PN junction diode. The cut wire quasistatic electric-dipole moment is designed to have resonance at 6.75 GHz, leading substantial cross-section for absorption. external microwaves create unidirectional current through rectifying action Using...
Spin-orbit interactions in evanescent fields have recently attracted significant interest. In particular, the transfer of Belinfante spin momentum perpendicular to propagation direction generates polarization-dependent lateral forces on particles. However, it is still elusive as how resonances large particles synergize with incident light's helicity and resultant forces. Here, we investigate these phenomena a microfiber-microcavity system where whispering-gallery-mode exist. This allows for...
We explore the ability of two LLMs -- GPT-4o and Claude Sonnet 3.5 to transcribe historical handwritten documents in a tabular format compare their performance traditional OCR/HTR systems: EasyOCR, Keras, Pytesseract, TrOCR. Considering form data, types experiments are executed: one where images split line by other entire scan is used as input. Based on CER BLEU, we demonstrate that outperform conventional methods. Moreover, also evaluated BLEU scores human evaluations better judge outputs...
Abstract Machine learning techniques, notably various deep neural network methods, are instrumental in processing extensive and intricate data sets engineering scientific fields. This paper shows how networks can inversely design cascaded-mode converting systems, particularly the waveguide gratings that implement selective mode conversion upon reflection. Neural map grating's physical features to scattering parameters of modes reflected from grating. The trained then be utilized converters...
Abstract We present a photonic mode converter based on grating structure, modeled and inversely designed by deep neural networks. The network maps the physical parameters of to responses, i.e., complex scattering representing reflected modes from structure. design different networks output magnitudes phases associated with multiple modes. Following training process, we use trained perform inverse desired parameters. effort provides full control converter. Our techniques help in creating rich...
Interferometers are essential tools for measuring and shaping optical fields, widely used in metrology, sensing, laser physics, quantum mechanics. They superimpose waves with a mutual phase delay, modifying light intensity. A frequency-dependent delay enables spectral filtering, routing, wave shaping, or multiplexing. Conventional Mach-Zehnder interferometers generate sinusoidal output intensities, limiting engineering capabilities. Here, we propose framework that uses interference of...
The spread of scientific knowledge depends on how researchers discover and cite previous work. adoption large language models (LLMs) in the research process introduces a new layer to these citation practices. However, it remains unclear what extent LLMs align with human practices, they perform across domains, may influence dynamics. Here, we show that systematically reinforce Matthew effect citations by consistently favoring highly cited papers when generating references. This pattern...
Over the past decades, humanity has tried to automate decision-making processes, often by optimizing a specific value function. But how do you make decision when significant risk is involved? Central under uncertainty lies assumption of ergodicity, which implies that temporal evolution can be predicted from ensemble averages. In this article, we study what happens reinforcement learning (RL) agent ergodicity broken in context. First, show traditional implementation, RL algorithms optimize...
According to general relativity, the frequency of electromagnetic radiation is altered by expansion universe. This effect--commonly referred as cosmological redshift--is utmost importance for observations in cosmology. Here we show that this redshift can be reproduced on a much smaller scale using an optical analogue inside dielectric metamaterial with time-dependent material parameters. To aim, apply framework transformation optics Robertson-Walker metric. We demonstrate theoretically how...
Recently, it was shown that a Mie particle in an evanescent field ought to experience optical forces depend on the helicity of totally internally reflected beam. As yet, direct measurement such helicity-dependent has been elusive, as widely differing force magnitudes three spatial dimensions place stringent demands measurement's sensitivity and range. In this study, we report simultaneous all components polarization-dependent by using 3D spectroscopy technique with femtonewton sensitivity....
Abstract Optical resonators enable the generation, manipulation, and storage of electromagnetic waves. The physics underlying their operation is determined by interference waves, giving rise to resonance spectrum. This mechanism causes limitations trade-offs resonator design, such as fixed relationship between free spectral range, modal linewidth, resonator’s refractive index size. Here, we introduce a new class optical resonators, generating resonances designing path through transverse mode...
We investigate the potential of transformation optics for design novel electromagnetic cavities. First, we determine dispersion relation bound modes in a device performing an arbitrary radial coordinate and discuss number such cavity structures. Subsequently, generalize our study to media that implement azimuthal transformations show can manipulate mode number. Finally, how combination allows perfect confinement subwavelength inside consisting right-handed materials only.
We demonstrate thermally limited force spectroscopy using a probe formed by dielectric microsphere optically trapped in water near surface. achieve resolution below 1 fN 100 s, corresponding to 2 Å rms displacement of the probe. Our measurement combines calibrated evanescent wave particle tracking technique and lock-in detection method. accuracy our method height-dependent exerted on an wave, results which are agreement with Mie theory calculations.Received 13 February...
Almost a decade ago, transformation optics established geometrical perspective to describe the interaction of light with structured matter, enhancing our understanding and control light. However, despite their huge technological relevance in applications such as optical circuitry, detection, actuation, guided electromagnetic waves along dielectric waveguides have not yet benefited from flexibility conceptual simplicity optics. Indeed, inherently imposes metamaterials only inside waveguide's...
Sculpting the optical near field In generation of electromagnetic fields, light can be broken down into two components: far field, which we generally see and is caused by propagating waves, field. The presents nonpropagating component at subwavelength distance from source radiation. Probing however, also provide detailed, information about emitting source. Ginis et al. present a nanophotonic-based method for controlling manipulating near-field landscape. This approach provides possibility...
We demonstrate that it is possible to confine electromagnetic radiation in cavities are significantly smaller than the wavelength of encapsulates. To this aim, we use techniques transformation optics. First, present a "perfect cavity" arbitrarily small size which such confined modes can exist. Furthermore, show these eigenmodes have continuous spectrum and bending losses absent, contrast what observed traditional microcavities. Finally, introduce an alternative cavity configuration less...
In addition to its extraordinary mechanical, thermal and electrical properties, graphene shows great potential in manipulating electromagnetic fields. One of the main advantages compared other materials is tunability conductivity, which can be achieved electrically by means a back gate, or optically through excitation photocarriers. Scientists from Belgium, Sweden United States demonstrate that this used novel setup for generation frequency combs. Traditionally, combs are generated using...