UCSD Ndao Lab

Observation of robust subwavelength phase singularity in chiral medium (Advanced Photonics)

Photonic devices that exhibit both sensitivity and robustness have long been sought; yet, these characteristics are thought to be mutually exclusive. Sensitivity enables a sensor to respond to external stimuli, whereas robustness embodies the inherent ability of a device to withstand weathering by these same stimuli. This challenge arises from the inherent contradiction between robustness and sensitivity in wave dynamics...

Integrating deep convolutional surrogate solvers and particle swarm optimization for efficient inverse design of plasmonic patch nanoantennas(Nanophotonics)

Plasmonic nanoantennas with suitable far-field characteristics are of huge interest for utilization in optical wireless links, inter-/intrachip communications, LiDARs, and photonic integrated circuits due to their exceptional modal confinement. Despite its success in shaping robust antenna design theories in radio frequency and millimeter-wave regimes, conventional transmission line theory finds...

Role of photonic angular momentum in all-optical magnetic switching(Physical Review B)

By examining the complex interactions between light and magnetism, this work uncovers the dominant role played by light’s spin angular momentum in magnetic all-optical switching (AOS) using Co/Pt ferromagnetic thin films.

Multi-channel broadband nonvolatile programmable modal switch(Optics Express)

Mode-division multiplexing (MDM) in chip-scale photonics is paramount to sustain data capacity growth and reduce power consumption. However, its scalability hinges on developing efficient and dynamic modal switches. Here, we present, for the first time, to the best of our knowledge, a novel multiport, broadband, non-volatile..

GPU-Accelerated and Memory-Independent Layout Generation for Arbitrarily Large-Scale Metadevices(Advanced Theory and Simulations)

Metadevices are of paramount interest and importance due to their exotic capabilities in light control and manipulation in the nano-scale regime. Various practical applications, including wearable devices, lasers, optical sensors, high-resolution microscopy, both virtual and augmented reality, and metasails, require large-scale metasurfaces...

Meta-Magnetic All-Optical Helicity Dependent Switching of Ferromagnetic Thin Films (Advanced Optical Materials)

To address the ever-increasing need for higher speed and density of information storage, recent developments in ultrafast optical switching have focused on deterministic control of magnetic properties of materials using femtosecond circularly polarized optical pulses. However, a monolithic high-speed optical helicity-dependent switching at room temperature has remained elusive...

Nonreciprocal lasing in topological cavities of arbitrary geometries (Science)

Resonant cavities are essential building blocks governing many wave-based phenomena, but their geometry and reciprocity fundamentally limit the integration of optical devices. We report, at telecommunication wavelengths, geometry-independent and integrated nonreciprocal topological cavities that couple stimulated emission from one-way photonic edge states to a selected waveguide output with an isolation ratio in excess of 10 decibels...

Symmetry-breaking-induced plasmonic exceptional points and nanoscale sensing (Nature Physics)

Singularities of open systems, known as exceptional points (EPs), have been shown to exhibit increased sensitivities, but the observation of EPs has so far been limited to wavelength-scaled systems subject to the diffraction limit. Plasmons, the collective oscillations of free electrons coupled to photons, shrink the wavelength of light to electronic and molecular length scales. We propose a novel approach...

Octave bandwidth photonic fishnet-achromatic-metalens (Nature Communications)

Planar structured interfaces, also known as metasurfaces, are continuously attracting interest owing to their ability to manipulate fundamental attributes of light, including angular momentum, phase, or polarization. However, chromatic aberration, limiting broadband operation, has remained a challenge for metasurfaces-based optical components and imagers...

Differentiating and quantifying exosome secretion from a single cell using quasi-bound states in the continuum (Nanophotonics)

One of the key challenges in biology is to understand how individual cells process information and respond to perturbations. However, most of the existing single-cell analysis methods can only provide a glimpse of cell properties at specific time points and are unable to provide cell secretion and protein analysis at single-cell resolution...

Recent Publications