arXiv subjects

Amberly Ricks

Publications and source records attributed to Amberly Ricks.

3 recordsLinked to original sources

arXiv2026

Trade-off between interface morphology and compositional homogeneity in AlGaAs/GaAs quantum wells revealed by multislice electron ptychography

AlGaAs/GaAs asymmetric coupled quantum wells (ACQWs) are promising platforms for enhanced second-order optical nonlinearities, with their performance strongly influenced by the structural quality of heterostructures. Flat interfaces, together with high compositional homogeneity, are generally desirable for optimizing device functionality. Here we show that sharp and flat AlGaAs/GaAs interface morphology dominates the second harmonic generation (SHG) response in AlGaAs/GaAs ACQWs, even when significant compositional fluctuations in Al/Ga occupancy are present within the AlGaAs layers. Using multislice electron ptychography, we resolve the three-dimensional (3D) interface morphology and compositional distribution in AlGaAs/GaAs ACQWs under distinct growth interruptions. Longer growth interruptions sharpen and flatten the AlGaAs/GaAs interfaces, but at the same time cause stronger compositional fluctuations in the AlGaAs layers. These findings clarify how growth interruption tunes quantum wells structures and provide direct guidance for quantum wells design in next-generation optoelectronic devices.

cond-mat.mtrl-sci↗

arXiv2026

Quantum-Well-Metasurface to Maximize Nonlinear Polarization

Nonlinear frequency conversion unlocks technologies ranging from telecommunications to quantum computation; however, weak nonlinearities and architectures that resist miniaturization currently limit devices. Here, we combine a bandstructure-engineered GaAs/AlGaAs heterostructure with a high quality factor dielectric metasurface to simultaneously tailor the intrinsic nonlinear susceptibility and optimize the electromagnetic field within the heterostructure. By engineering a resonant interband transition, we realize a large second-order nonlinear tensor element, 1.6 nm/V at 1.57 um wavelength. We then make it free-space-accessible and boost the effective nonlinearity to ~ 14 nm/V using a metasurface patterned on the material. Our proof-of-concept experiment establishes that interband transition engineering and metasurfaces accessing otherwise unusable nonlinear tensor elements enable giant effective nonlinearities in the near-infrared to visible spectrum. This addresses material and device-level constraints in nonlinear photonics, providing a scalable route to compact, efficient devices.

physics.optics↗

arXiv2026

Enhanced Interband Optical Nonlinearities from Coupled Quantum Wells

The recent, rapid advances in nonlinear chipscale nanophotonics in the visible and near-infrared have been largely driven by manipulating the local dielectric environment proximate to decades-old workhorse bulk nonlinear optical materials, rather than increasing the inherent strength of their nonlinear response. While proposed decades ago, we demonstrate the first experimental realization of a new class of designer nonlinear materials that leverage the interband optical transition in asymmetric structures to provide strong second order susceptibility, $χ^{(2)}$. Using simple AlGaAs/GaAs coupled quantum wells operating in the near-infrared as a prototype, we observed strong second harmonic generation enhancement of 1550 nm to 775 nm over bulk controls. Extracted $χ^{(2)}$ values were as high as 2750 pm/V, which is $>$7x that of bulk GaAs. Furthermore, measured susceptibilities agreed well with quantum mechanical calculations of $χ^{(2)}$ using layer profiles extracted from electron microscopy. Growth interruptions were employed to improve interfacial abruptness in response to electron microscopy characterization, resulting in increased $χ^{(2)}$ toward the simulation predictions for ideal heterointerfaces. More complex layer designs showed predicted $χ^{(2)}$ up to 7 nm/V. Such materials are anticipated to find myriad applications, including entangled photon generation at telecommunications wavelengths for chipscale quantum information processing.

physics.optics↗