arXiv subjects

Robert Leonard

Publications and source records attributed to Robert Leonard.

4 recordsLinked to original sources

arXiv2026

Enhanced stability from co-resonant cavities in a monolithic array

We demonstrate a micro-Fabry-P\'erot cavity array through laser etching of high-surface-quality mirrors onto a single fused silica substrate. A cavity finesse of $4750\pm 200$ was achieved with a simple array design with $500~\mu m$ cavity length, $100~\mu m$ diameter micromirrors and $300~\mu m$ transverse separation. Arrays with up to 12 cavities were simultaneously tested for single mode operation, and absolute frequency measurements correlated strongly with the etched depth as measured by profilometry. Simultaneous measurements of the absolute resonant frequency for neighboring cavities showed a factor of 5 common-mode cavity drift reduction. Arrays of such cavities can be employed in chip-scale cavity QED networks (current cooperativity estimates are at the border of strong coupling for $^{87}$Rb atoms, $C=1$) as well as for precise laser stabilization at nearby wavelengths on a chip.

physics.optics↗

arXiv2025

Characterization of Gradient Index Fibers

Gradient index (GRIN) fibers are used to improve the design of many fiber optic devices. However, the properties of the GRIN fiber must be determined to optimally engineer a device which incorporates GRIN fiber components. The index of refraction of most GRIN fibers varies quadratically in the radial direction, where the quadratic coefficient is characterized by the gradient index constant $g$. We measured $g$ for Thorlabs GIF50C GRIN fiber at both $780~\mathrm{nm}$ and $1550~\mathrm{nm}$ using equipment which is commonly available in an optics laboratory. This measurement was achieve by profiling the beam exiting various lengths of GRIN fiber. A custom-built beam profiler was used, which enabled the beam position to be referenced with respect to the facet of the GRIN fiber. We report a gradient index constant of $0.0057~\mathrm{\mu m}^{-1} \pm 0.0001~\mathrm{\mu m}^{-1}$ at $780~\mathrm{nm}$ and $0.0055~\mathrm{\mu m}^{-1} \pm 0.0001~\mathrm{\mu m}^{-1}$ at $1550~\mathrm{nm}$. These results are in close agreement with previously reported gradient index constant measurements made for different wavelengths.

physics.optics↗

arXiv2025

Atom-Chip Compatible Optical Lattice

A lattice beam configuration which results in an isotropic 3D trap near the surface of an atom chip is described. The lattice is formed near the surface of a reflectively coated atom chip, where three incident beams and three reflected beams intersect. The coherent interference of these six beams form a phase-stable optical lattice which extends to the surface of the atom chip. The lattice is experimentally realized and the trap frequency is measured. Degenerate Raman sideband cooling is performed in the optical lattice, cooling 80 million atoms to 1.1 $\mu$K.

quant-ph↗

arXiv2025

Iterative Refinement of Arbitrary Micro-Optical Surfaces

We introduce an adaptive optical refinement method enabling ultra-precise micro-milling of arbitrary surfaces. Through repeated iteration, our method reduces surface error without requiring significant specific surface engineering. This remediates the long sample preparation times and lack of refinement capability that previously reported methods suffer from. The iterative refinement milling method was used to produce spherical mirrors with small radii of curvature and low surface roughness for use in micro Fabry-Perot cavities. We demonstrate the use of this adaptive process to produce a variety of arbitrary surface geometries on both optical fiber tips as well as optical flats. We additionally discuss our capability to apply iterative refinement milling adaptively to various materials, including to construct GRIN lenses.

physics.optics↗