arXiv subjects

Lan Hoang Mai

Publications and source records attributed to Lan Hoang Mai.

3 recordsLinked to original sources

arXiv2026

Versatile Sleeve-and-Bulk Fabrication of Inversely Designed Nanophotonic Structures with High Pattern Transfer Fidelity

Inverse design is a powerful computational tool for generating nanophotonic devices that should outperform their traditionally designed counterparts. However, translating these theoretical gains into physical devices is challenging because the irregular and non-intuitive features that make inversely designed structures so effective also make them exceptionally difficult to fabricate, typically necessitating substantial process optimization unique to each device design. We describe a versatile two-step nanofabrication process that achieves pattern transfer fidelity in excess of 90% for each of three distinct inverse device designs with no device-specific process optimization.

physics.optics↗

arXiv2026

A high-Q Split Cavity Enabling Independent Electrical Tuning of two Quantum Dots

Cavity-mediated strong coupling is an essential tool for quantum photonics. However, the inherent inhomogeneity in ensembles of matter-based qubits necessitates independent tuning to bring more than one qubit into resonance with a single cavity mode. We present the design, fabrication, and characterization of a GaAs-based photonic crystal split cavity that consists of two electrically-distinct portions, which preserves the ability to apply independent electric fields that would independently tune two distinct qubits based on InAs Quantum Dots (QDs) into resonance with a cavity mode. We show that this device, despite the cut required to electrically isolate the two halves, achieves an average Q $\geq 20,000$, sufficient to enter the strong coupling regime. Moreover, we show that the Q is limited primarily by the precision and accuracy of the e-beam lithography tool, rather than by sidewall scattering. This result creates a realistic experimental path toward devices that use controlled interactions between two InAs QDs, mediated by strong coupling to a single cavity mode, to generate multi-dimensional photon graph states.

physics.optics↗

arXiv2026

Universality and anisotropy of the Photonic Urbach Tail

Disorder in photonic crystals and waveguides creates states inside the photonic band gap. These states are often described as Lifshitz tails despite exhibiting energy distributions inconsistent with Lifshitz statistics near the band edge. Here we show that in photonic-crystal waveguides with intentionally engineered anisotropic disorder, the band-edge tail accessible experimentally follows an Urbach law universally, with cumulative statistics $F(Δ)=\exp[-(Δ/α)^β]$, where $Δ$ is the spectral detuning from the band edge, and an exponent $β\approx 1$ independent of disorder strength and orientation. In contrast to Lifshitz behavior, the density of states is maximal at the band edge and decays into the gap. Crucially, we find that the Urbach energy $α$ is anisotropic, with a pronounced directional splitting and qualitatively different scaling for disorder parallel and perpendicular to the waveguide axis. These conclusions are supported by quantitative agreement between optical measurements of GaAs photonic-crystal waveguides and full-vector simulations. The anisotropic Urbach energy emerges as a sensitive probe of disorder-mode coupling and a practical metric to characterize structural disorder in photonic devices.

physics.optics↗