arXiv subjects

Jacob Williamson

Publications and source records attributed to Jacob Williamson.

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

Simple Method for Stripping Polyimide-Coated Optical Fiber

We present a simple method for removing polyimide coatings from optical fibers using inexpensive and readily available solvents. Impacts of solvent mixing ratios, soak temperature, material expansion, wicking, and drying are described to provide empirical context for the method. We find that soaking fibers for six hours in a 2:1 mixture of methanol to acetone at room temperature enables easy stripping of a length slightly greater than the soak length.

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↗

arXiv2024

Compact Cavity-Enhanced Aerosol Detector using Incoherent Light Sources

We have realized a compact optical particle counter utilizing enhancement of light scattering within a high finesse Fabry-Perot optical cavity. In contrast to laser-based approaches such as cavity ringdown spectroscopy we use the light stream from both superluminescent and light-emitting diodes that have no longitudinal coherence. This eliminates the vibration sensitivity that is typical of laser-based cavity methods. The use of the transmission mode of detection allows us to reduce the cavity mirror separation to below 1 cm, with no obvious limit to miniaturization. Typical light scattering instruments are larger, in part due to their sensitivity to background signals from the light source. Our approach paves the way toward a new generation of compact and portable instruments. A simultaneous comparison of the scattering signals with a commercial particle counter shows that our cavity is also sensitive to ultrafine particles below 300 nm diameter that are typically not recorded in such counters.

physics.optics↗