Fiber lab
Fabricating optical fibers for coherent atom-light interfaces
Fiber Fabry-Perot cavities (FFPCs) are integral to many scientific and technological applications, including cavity quantum electrodynamics experiments, tunable optical filters, cavity-based spectroscopy of gases. To manufacture these FFPCs, our team is building an advanced, auotomated fabrication system for creating curved mirrors on the end-facets of optical fibers.
Main part of the experimental setup featuring a water-cooled, 50W CO2 Laser and the white light interferometer.
The curvature is precisely formed by shooting the end facets with a COâ‚‚ laser, which operates at a wavelength of 9.3 µm and has a maximum output power of approximately 50W. Using an acousto-optic modulator (AOM), the beam pulse can be manipulated as required to improve the desired fiber ablation.
In our setup, we make use of white light interferometry to monitor and measure the created profile throughout the production process, allowing for iterative optimization and sub-nanometer precision.
Image of a fiber end-facet taken with the white-light interferometer
To reconstruct the shape of the optical fiber's end-facets from the white light interferometry pattern, we employ a phase unwrapping algorithm.
Reconstructed shape of the optical fiber's end-facets from the white light interferometry pattern.
This approach aims to produce high finesse cavities, which are essential for many quantum simulation setups like the currently build setup of our group, that uses an tweezer-loaded array of neutral atoms inside a FFPC.