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arXiv · 2508.08857

A Broadband Squeezed Light Source for Table-Top Interferometry

Fabio Bergamin·Nikitha Kuntimaddi·Abhinav Patra·Stephanie Montoya·Moritz Mehmet·Katherine Dooley·Hartmut Grote·Henning Vahlbruch
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Abstract

We report on the characterisation of one of two broadband squeezed light sources developed for the Quantum Enhanced Space-Time (QUEST) experiment, using balanced homodyne detection. QUEST consists of a pair of co-located, table-top, power-recycled Michelson interferometers designed to probe stationary space-time fluctuations. The interferometers are designed to be shot-noise limited in the frequency range from 1 to 200 MHz, and squeezed light will be employed with the goal to reduce the shot noise by 6 dB at frequencies inside the linewidth of the optical parametric amplifier (OPA). We directly observed up to 6.8 dB of squeezing and maintained at least 3 dB of squeezing across the full 100 MHz measurement bandwidth. After accounting for the dark noise contribution, the inferred squeezing level increased to 8.6 dB. Our squeezed light source is based on a hemilithic OPA with a 43.6 mm round-trip optical length and a linewidth of 138 MHz, making it the broadest-linewidth device to date among those suitable for long-term operation.

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Fabio Bergamin, Nikitha Kuntimaddi, Abhinav Patra, Stephanie Montoya, Moritz Mehmet, Katherine Dooley, Hartmut Grote, Henning Vahlbruch. 2025-08-12. A Broadband Squeezed Light Source for Table-Top Interferometry. https://doi.org/10.1088/1367-2630%2Fae2987

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