SAMOP 2023 – scientific programme
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QI: Fachverband Quanteninformation
QI 22: Quantum Technologies II (joint session Q/MO/QI)
QI 22.3: Talk
Wednesday, March 8, 2023, 15:15–15:30, E214
Squeezed States of Light for Future Gravitational Wave Detectors at a Wavelength of 1550 nm — •Fabian Meylahn1,2, Benno Willke1,2, and Henning Vahlbruch1,2 — 1Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-30167 Hannover, Germany — 2Leibniz Universität Hannover, D-30167 Hannover, Germany
The generation of strongly squeezed vacuum states of light is a key technology for future ground-based gravitational wave detectors (GWDs) to reach sensitivities beyond their quantum noise limit. For some proposed observatory designs, an operating laser wavelength of 1550 nm or around 2 μm is required to enable the use of cryogenically cooled silicon test masses for thermal noise reduction. Here, we present the first the direct measurement of up to 11.5 dB squeezing at 1550 nm over the complete detection bandwidth of future ground-based GWDs ranging from 10 kHz down to below 1 Hz. Furthermore, we directly observe a quantum shot-noise reduction of up to 13.5 dB at megahertz frequencies. This allows us to derive a precise constraint on the absolute quantum efficiency of the photodiode used for balanced homodyne detection. These results hold important insight regarding the quantum noise reduction efficiency in future GWDs, as well as for quantum information and cryptography, where low decoherence of nonclassical states of light is also of high relevance.