Non-Classical Light

Non-Classical Light

The generation of squeezed states of light and the application in quantum metrology, measurement induced entanglement and high-precision spectroscopy.

Contributions to QuantumFrontiers

  • A worldwide leading collaboration for squeezed light source development and their application in gravitational wave detectors
  • Generation and application of squeezed vacuum states of light for the following applications:
    • Current and 3rd generation gravitational wave detectors
    • Sub-standard quantum limit interferometry
    • Quantum information
    • Measurement induced entanglement / entanglement swapping
    • Quantum teleportation
    • High-precision spectroscopy
  • Enhanced-sensitivity phase measurements using non-classical light at high frequencies
  • Realisation of a polarisation non-degenerate, two-mode squeezer serving as a “negative mass oscillator” for coherent quantum noise cancellation
  • Use of squeezed light to sense laser power noise below the classical quantum limit

Collaborative Innovation

  • Realizing and implementing a nano-structured cavity mirror as an input coupler and squeezer, which provides a large polarisation non-degeneracy for low angles of incidences. (Heurs, Junker, Wilken, Schimanski, Nived LUH, AEI / Kroker TU Braunschweig)
  • Defining requirements and developing squeezed light sources at 1064nm and 1550nm; wavelengths tailored for high-precision metrology lab experiments and the application in gravitational wave detectors (Vahlbruch, Meylahn, Mehmet, Willke, Lück, AEI, LUH)
  • Developing compact, standalone squeezed-light-sources for in-air and in-vacuum application (Meylahn, Vahlbruch, Mehmet, AEI, LUH)
  • Improving the low frequency (<10Hz) squeezing performance at 1550nm (Meylahn, Willke, Vahlbruch, AEI, LUH)
  • Analysing and mitigating decoherence effects to reach new squeezing level benchmarks (Schimanski, Nived, Wilken, Junker, Heurs, Meylahn, Mehmet, Vahlbruch, Venneberg AEI, LUH)
  • Developing fiber-coupled modular sub-systems for the generation of auxiliary squeezed vacuum control fields and squeezing detection (Meylahn, Vahlbruch, Willke AEI, LUH)
  • Investigating non-classical light enhanced laser power stabilization schemes and generation of bright squeezed states (Venneberg, Trad Nery, Vahlbruch, Willke AEI, LUH)

Scientific Output

  • Publications

    Aritomi N, Zhao Y, Capocasa E, Leonardi M, Eisenmann M, Page M et al. Demonstration of length control for a filter cavity with coherent control sidebands. Physical Review D. 2022 Nov 10;106(10). 102003.

    Heinze J, Danzmann K, Willke B, Vahlbruch H. 10 dB Quantum-Enhanced Michelson Interferometer with Balanced Homodyne Detection. Physical review letters. 2022 Jul 15;129(3). 031101.

    Heinze J, Willke B, Vahlbruch H. Observation of Squeezed States of Light in Higher-Order Hermite-Gaussian Modes with a Quantum Noise Reduction of up to 10 dB. Physical review letters. 2022 Feb 25;128(8). 083606.

    Junker J, Wilken D, Johny N, Steinmeyer D, Heurs M. Frequency-Dependent Squeezing from a Detuned Squeezer. Physical review letters. 2022 Jul 14;129(3). 033602.

    Meylahn F, Willke B, Vahlbruch H. Squeezed States of Light for Future Gravitational Wave Detectors at a Wavelength of 1550 nm. Physical review letters. 2022 Sep 16;129(12). 121103.

    Junker J, Wilken D, Huntington E, Heurs M. High-precision cavity spectroscopy using high-frequency squeezed light. Optics express. 2021 Feb 10;29(4):6053-6068.


    Lough JD, Schreiber E, Bergamin F, Grote H, Mehmet M, Vahlbruch H et al. First Demonstration of 6 dB Quantum Noise Reduction in a Kilometer Scale Gravitational Wave Observatory. Physical review letters. 2021 Jan 26;126(4). 041102.

    Nery MT, Venneberg JR, Aggarwal N, Cole GD, Corbitt T, Cripe J et al. Laser power stabilization via radiation pressure. Optics letters. 2021 Apr 14;46(8):1946-1949.

    Trad Nery M. Laser power stabilization via radiation pressure. Nature Reviews Physics. 2021 Okt;3(10):677.


    Vermeulen SM, Relton P, Grote H, Raymond V, Affeldt C, Bergamin F et al. Direct limits for scalar field dark matter from a gravitational-wave detector. NATURE. 2021 Dez 16;600(7889):424-428.

    Heinze J, Vahlbruch H, Willke B. Frequency-doubling of continuous laser light in Laguerre–Gaussian modes LG0,0 and LG3,3. Optics letters. 2020 Sep 15;45(18):5262-5265.


    Heinze J, Vahlbruch H, Willke B. Numerical analysis of LG3,3second harmonic generation in comparison to the LG0,0case. Optics express. 2020 Nov 10;28(24):35816-35832.

    Mehmet M, Vahlbruch H. The Squeezed Light Source for the Advanced Virgo Detector in the Observation Run O3. Galaxies. 2020 Nov 26;8(4):1-10. 79.


    Nery MT, Danilishin SL, Venneberg JR, Willke B. Fundamental limits of laser power stabilization via a radiation pressure transfer scheme. Optics letters. 2020 Jul 10;45(14):3969-3972.

    Zhao Y, Aritomi N, Capocasa E, Leonardi M, Eisenmann M, Guo Y et al. Frequency-Dependent Squeezed Vacuum Source for Broadband Quantum Noise Reduction in Advanced Gravitational-Wave Detectors. Physical review letters. 2020 Mai 1;124(17). 171101.


    Virgo Collaboration, Vahlbruch H, Lück H, Danzmann K, Mehmet M. Quantum Backaction on kg-Scale Mirrors: Observation of Radiation Pressure Noise in the Advanced Virgo Detector. Physical review letters. 2020 Sep 22;125(13). 131101.

    Mehmet M, Vahlbruch H. High-efficiency squeezed light generation for gravitational wave detectors. Classical and Quantum Gravity. 2019 Jan 10;36(1). 015014.


    Virgo Collaboration, Vahlbruch H, Lück H, Danzmann K, Mehmet M. Increasing the Astrophysical Reach of the Advanced Virgo Detector via the Application of Squeezed Vacuum States of Light. Physical review letters. 2019 Dez 5;123(23). 231108.

TG Members

  • Involved Members and their Relevant Expertise
    Members Institution Relevant Expertise
    Henning Vahlbruch, Leader AEI/LUH Generation of squeezed states
    Harald Lück AEI/LUH Next Generation Gravitational Wave Observatories; Sub-Standard Quantum Limit Interferometry
    Benno Willke AEI/LUH Squeezed Light Sources; Advanced Light Sources
    Marina Trad Nery AEI/LUH Advanced Light Sources
    Moritz Mehmet AEI/LUH Squeezed light sources
    Fabian Meylahn AEI/LUH Squeezed light sources
    Jasper Venneberg AEI/LUH Squeezed light sources
    Michèle Heurs AEI/LUH Backaction-Evading Techniques; Squeezed Light Sources
    Jonas Junker AEI/LUH Backaction-Evading Techniques; Squeezed Light Sources
    Dennis Wilken AEI/LUH Backaction-Evading Techniques; Squeezed Light Sources
    Manuel Schimanski AEI/LUH Backaction-Evading Techniques; Squeezed Light Sources
    Nived Johny AEI/LUH Backaction-Evading Techniques; Squeezed Light Sources