Neil V. Sapra

Tuning the photon statistics of a strongly coupled nanophotonic system

We demonstrate the generation of single- and two-photons at a time from a quantum dot-photonic crystal resonator system. Controlling the detuning between emitter and cavity allows us to drive a nonlinear ladder of hybridized light-matter states.

Fully-automated optimization of grating couplers

We present a gradient-based algorithm to design general 1D grating couplers without any human input from start to finish, including a choice of initial condition. We show that we can reliably design efficient couplers to have multiple functionalities in different geometries, including conventional couplers for single-polarization and single-wavelength operation, polarization-insensitive couplers, and wavelength-demultiplexing couplers. In particular, we design a fiber-to-chip blazed grating with under 0.2 dB insertion loss that requires a single etch to fabricate and no back-reflector.

On-chip architecture for self-homodyned nonclassical light

In the last decade, there has been remarkable progress on the practical integration of on-chip quantum photonic devices, yet quantum-state generators remain an outstanding challenge. Simultaneously, the quantum-dot photonic-crystal-resonator platform has demonstrated a versatility for creating nonclassical light with tunable quantum statistics thanks to a newly discovered self-homodyning interferometric effect that preferentially selects the quantum light over the classical light when using an optimally tuned Fano resonance. In this work, we propose a general structure for the cavity quantum electrodynamical generation of quantum states from a waveguide-integrated version of the quantum-dot photonic-crystal-resonator platform, which is specifically tailored for preferential quantum-state transmission. We support our results with rigorous finite-difference time-domain and quantum-optical simulations and show how our proposed device can serve as a robust generator of highly pure single- and even multiphoton states.

Inverse Design and Demonstration of a Compact on-Chip Narrowband Three-Channel Wavelength Demultiplexer

In wavelength division multiplexing (WDM) schemes, splitters must be used to combine and separate different wavelengths. Conventional splitters are fairly large with footprints in hundreds to thousands of square microns, and experimentally-demonstrated MMI-based and inverse-designed ultra-compact splitters operate with only two channels and large channel spacing (

On-Chip Laser-Power Delivery System for Dielectric Laser Accelerators

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Tuning the Photon Statistics of a Strongly Coupled Nanophotonic System

100 nm). Here we inverse design and experimentally demonstrate a three-channel wavelength demultiplexer with 40 nm spacing (1500 nm, 1540 nm, and 1580 nm) with a footprint of 24.75

Towards a Fully Integrated Accelerator on a Chip: Dielectric Laser Acceleration (DLA) From the Source to Relativistic Electrons

\mu\mathrm{m}^2

Fabrication Constrained Inverse Design of a 3-channel Wavelength Demultiplexer

. The splitter has a simulated peak insertion loss of -1.55 dB with under -15 dB crosstalk and a measured peak insertion loss of -2.29 dB with under -10.7 dB crosstalk.