A highly efficient photodetector for squeezed light measurement in the gigahertz range

authored by: Dennis Wilken, Jonas Junker, Michèle Heurs
Abstract: Squeezed light plays a crucial role in state-of-the-art quantum metrology and quantum information experiments. There is significant interest in utilizing squeezed states at high MHz and GHz frequencies. However, past efforts to build suitable photodetectors at these frequencies have yet to yield the required high quantum efficiency. Here, we present the development of a high-frequency balanced photodetector with near-unity quantum efficiency, realized with off-the-shelf components. The detector operates in balanced mode up to approximately 500 MHz, above which the differential frequency response limits its performance. To obtain high sensitivity above 500 MHz, the detector can be efficiently used in an unbalanced homodyne detection scheme. We employ our detector in this unbalanced mode to measure a squeezing comb up to 6.4 GHz, achieving a squeezing level of up to 10.7 dB. By sharing our experience, specifically in identifying the unequal frequency response as a limiting factor, we aim to enable and advance further developments in the field.
Organisation(s): Institute of Gravitation Physics
External Organisation(s): Technical University of Denmark
Deutsches Elektronen-Synchrotron (DESY)
Type: Article
Journal: Applied physics letters
Volume: 127
ISSN: 0003-6951
Publication date: 06.10.2025
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy (miscellaneous)
Electronic version(s): https://doi.org/10.1063/5.0290396 (Access: Open)

BibTeX

@article{8574d0716afb4c789f9227a9e4f00732,
title = "A highly efficient photodetector for squeezed light measurement in the gigahertz range",
abstract = "Squeezed light plays a crucial role in state-of-the-art quantum metrology and quantum information experiments. There is significant interest in utilizing squeezed states at high MHz and GHz frequencies. However, past efforts to build suitable photodetectors at these frequencies have yet to yield the required high quantum efficiency. Here, we present the development of a high-frequency balanced photodetector with near-unity quantum efficiency, realized with off-the-shelf components. The detector operates in balanced mode up to approximately 500 MHz, above which the differential frequency response limits its performance. To obtain high sensitivity above 500 MHz, the detector can be efficiently used in an unbalanced homodyne detection scheme. We employ our detector in this unbalanced mode to measure a squeezing comb up to 6.4 GHz, achieving a squeezing level of up to 10.7 dB. By sharing our experience, specifically in identifying the unequal frequency response as a limiting factor, we aim to enable and advance further developments in the field.",
author = "Dennis Wilken and Jonas Junker and Mich{\`e}le Heurs",
note = "Publisher Copyright: {\textcopyright} 2025 Author(s).",
year = "2025",
month = oct,
day = "6",
doi = "10.1063/5.0290396",
language = "English",
volume = "127",
journal = "Applied physics letters",
issn = "0003-6951",
publisher = "American Institute of Physics",
number = "14",
}