We present an efficient spin-photon interface for free-space vertical emission coupling. Using a dipole model, we show that our design achieves a far-field collection efficiency of 96% at the numerical aperture of 0.7 with a 95% overlap to a Gaussian mode. Our approach is based on a dual perturbation layer design. The first perturbation layer extracts and redirects the resonant mode of a diamond microdisk resonator around the optical axis. The second perturbation layer suppresses side lobes and concentrates most of the light intensity near the center. This dual-layer design enhances control over the farfield pattern and also reduces alignment sensitivity. Additionally, the implemented dipole model performs calculations 3.2 × 10^6 times faster than full-wave FDTD simulations. These features make the design promising for quantum information applications.

We demonstrate a simulation technique to model distributed coupling between electronic circuits and multiple eigenmodes of a metallic cavity using spice-type lumped element circuit simulators. We first solve for the first few eigenmodes of the cavity and the circuit’s large microstrips using the finite element method. We integrate the electric and magnetic fields of the solution along certain planes to extract RLC circuit parameters for each eigenmode and mutual inductances between eigenmodes and a simple circuit’s larger traces. We then use those parameters in an LTSpice simulation to model how the cavity interferes with the circuit.

Quantum Conference Key Agreement (QCKA) allows a group of users to establish a shared secret key. We describe the experimental characterization of a “Green Machine” photonic integrated circuit (PIC) and its simulated performance in QCKA.

We design a cavity-based frequency-multiplexed photon pair source by combining full-wave photonic simulation with a novel quantum theoretical treatment. Simulation predicts the joint spectral intensity function and pair generation rates greater than 1 GHz/mode.

We present a theory for optical binding that incorporates second- and third-order nonlinear optical interactions, extending beyond the linear optical binding models typically considered in previous work. By that fundamentally reshape the spatial organization of bound particle arrays. This nonlinear optical binding regime offers greater tunability and external control, enabling dynamically reconfigurable nanomaterials with adaptable structural properties.

Electro-optic modulator (EOM) polarization controllers offer precise manipulation of optical polarization states, but require multiple independent voltage sources, significantly increasing system complexity and cost. In this work, we present a low-cost, compact, scriptable voltage driver that enables six independently controlled bipolar voltage outputs derived from a single pair of fixed positive and negative voltage sources. Utilizing a Raspberry Pi Pico, serial peripheral interface (SPI)-controlled digital potentiometers, and efficient voltage regulation, our device provides the voltage control necessary for full polarization state transformation. This solution offers a cost-effective alternative to expensive commercial products, filling a gap in the market where dedicated devices for high-precision EOM control are currently lacking.

In this work, we perform on-chip quantum random number generation (QRNG) that uses a novel differential amplifier configuration for conjugate homodyne detection. Leveraging separate integrated photonics and integrated analog circuit platforms, we present an alternative method for QRNG. This approach exploits the observable Ẑ, derived from the sum of squared conjugate quadrature distributions which we compare to the traditional single quadrature approach. Utilizing this method, we report a shot noise clearance (SNC) of 25.6 dB and a common mode rejection ratio (CMRR) of 69 dB for our homodyne detection system. We used a variety of design tools to model and predict performance and compare results with our measurements. The realization of our QRNG system consists of a 90 optical hybrid, a dual differential transimpedance amplifier (TIA), and a field-programmable gate array (FPGA) used for the real-time post-processing to produce a uniform random bitstream. The randomness extraction is implemented using a Toeplitz hashing algorithm and is validated by the National Institute of Standards and Technology (NIST) randomness test suites.

In this paper, we introduce a horizontally oriented photophoretic "boat" trap that is capable of capturing and self-loading the largest reported (radius >= 1 mu m) photophoreticaly trapped solid gold particles in air for more than 1 h. Once trapped, particles are held stably, without hopping, even as the trap is modified to scan axially or expanded to a larger size to increase the capture cross section. We theoretically present and experimentally demonstrate each of these affordances.

We present topology optimization enhancements for thin-film lithium niobate, enabling optimization for structures with nonvertical sidewalls and anisotropic media. We validate our enhancements by optimizing and measuring the first topology optimized polarization demultiplexing grating coupler on thin-film lithium niobate.

Hybrid photonic-electronic circuits involving crossdomain feedback signals are difficult to validate and troubleshoot. This paper describes an approach to model and validate an offset-cancellation loop for a hybrid transimpedance amplifier (TIA) using all-electronic circuits. An equivalent electrical model is developed for the tunable interferometer attenuators used for offset trimming, and it includes test features to extract the system performance. The stability analysis of the system shows 75 ◦ of phase margin and 102 dB of gain margin. Measurement results demonstrate good agreement with analysis and successful TIA offset cancellation.

We propose a scalable design for a spin-photon interface to a color center in a diamond microdisk. The design consists of a silicon oxynitride hexagonal lattice overlaid on a diamond microdisk to enable vertical emission from the microdisk into low-numerical aperture modes, with quantum efficiencies as high as 45\% for a tin vacancy (SnV) center. Our design is robust to manufacturing errors, potentially enabling large scale fabrication of quantum emitters coupled to optical collection modes. We also introduce a novel approach for optimizing the free space performance of a complex structure using a dipole model, achieving comparable results to full-wave finite difference time domain simulations with a 650,000 times reduction in computational time.

Microdroplet resonators provide an excellent tool for optical studies of water, but water microdroplets are difficult to maintain outside a carefully controlled environment. We present a method for maintaining a water microdroplet resonator on a 3D-printed hydrophobic surface in an ambient environment. The droplet is maintained through a passive microfluidic system that supplies water to the droplet through a vertical channel at a rate equivalent to its evaporation. In this manner, we are able to create and passively maintain water microdroplet resonators with quality factors as high as 3×108.

We present a homodyne detection system that uses a novel differential amplification scheme with potential applications for quantum key distribution (QKD), quantum random number generation (QRNG) or quantum state tomography.

We measured correlated X-ray photons from parametric down conversion as a means of creating entangled X-rays. Using a Laue diffraction geometry, we measured the efficiency of this process from single crystal diamond samples.

Despite its importance in environmental, biological, geological, and extraterrestrial fields of study, ice is still poorly understood. Ice is underutilized as an optical material partly due to the disclarities often found in ice. This paper presents a method of creating frozen microdroplets for use as optical devices, especially optical resonators. We use a 3-D printed device to shape water droplets into approximate spheres. Subzero temperatures are applied to one side of the droplet in a humidity-controlled environment to freeze the droplet while maintaining its clarity. We were able to freeze clear droplets and prevent sublimation or deposition by controlling humidity.

We present a method of maintaining a water microdroplet resonator using a 3D printed microfluidic system, which operates in an ambient environment and allows for quality factors as high as 200 million.

Density-based topology-optimization can be used to design photonic components that are more compact and broadband than their traditionally designed counterparts. In this paper, a 90° 2×2 coupler is designed using MIT's Electromagnetic Equation Propagation software's adjoint variable method. The design was optimized over the wavelengths 1500–1600 nm in a 4 × 4 µm. design region. The final design meets the design rule constraints of minimum linewidth and line spacing for a standard electron beam lithography process. It also has an insertion loss of less than 0.085dB for all wavelengths and a port imbalance of less than 1%.

We investigate the photonic and electronic elements of a quantum random number generator based on vacuum state homodyne detection. We account for photodiode responsivity, optical beam splitting ratio, and optical path length in balancing the detector's photocurrents. Finally, the quantum to classical noise ratio is increased through the design of an operational amplifier, including its common mode rejection ratio, bandwidth, gain, and classical noise. A quantum to classical noise ratio of. 064 is achieved and the result is analyzed for improvement in future work.

We present a computational study of Purcell factor enhancement for a novel hybrid-plasmonic ring resonator using a novel implementation of the body-of-revolution (BOR) finite-difference time-domain (FDTD) method. In this hybrid structure, a dielectric slot ring is surrounded by a metallic ring such that a hybrid plasmonic mode is generated within two thin low-index gaps. The surrounding metallic ring decreases the binding loss for small ring radii, leading to high-quality factors and mode-field confinement. The hybrid resonator shows high quality-factor values above 10 3 and small mode volumes down to 10 − 3 λ n 3 simultaneously, thus providing large Purcell factors ( F p > 10 4 ). The distributed strong confinement within two gaps renders the proposed resonator useful for multi-emitter applications.

In this work we utilize topology optimization to design and simulate an etching pattern for a layered diamond microdisk for efficient coupling from a nitrogen vacancy center emitter to free space. Other methods of coupling a waveguide to a quantum emitter are also explored in simulation.