In our publication we compare different multiplexing architectures of single-photon detectors. We use the purity of the measurement outcomes to characterize their photon-number-resolving ability. Additionally, we calculate the amount of information the measurement outcomes of the different devices can extract from a Hilbert space with a certain dimension. We could confirm that detectors with more multiplexing outcomes enable a higher…
In our new publication we show the operation of lithium niobate modulators at cryogenic temperatures. We have previously shown the operation of a polarisation converter at 1K. To show the full capabilities of lithium niobate modulators at cryogenic temperature we characterised a phase modulator, directional coupler, and a polarisation converter. These modulators were characterised in respect to their modulation voltage and wavelength dependence…
Six members of the MQO group went to the Conference on Lasers and Electro-Optics (CLEO) from May 15th-20th, 2022 in San Jose. We presented five contributions:
Jan Philipp Höpker - Two-Mode Photon-Number Correlations Created by Measurement-Induced Nonlinearity (Poster) Frederik Thiele - Cryogenic Optical Biasing of a Superconducting Nanowire Single Photon Detector With a Photodiode (Talk) Maximilian Protte - Direct Laser Lithography:…
The week before the Conference on Lasers and Electro-Optics (CLEO) two members of the MQO group (Jan Philipp Höpker and Maximilian Protte) visited the National Institute of Standards and Technology (NIST) in Boulder, Colorado, USA. They were shown their laboratories and had great discussions about superconducting detector technology.
Jun.-Prof. Dr. Tim Bartley, physicist at Paderborn University receives a "ERC Starting Grant" from the European Research Council. The highly endowed "Starting Grant" supports particularly promising scientists who are at the beginning of an independent research career.
The project „Quantum Engineering Superconducting Array Detectors in Low-Light Applications" (QuESADILLA) will focus on developing efficient single-photon detectors for tasks in…
In our paper, we demonstrate the fabrication of micron-wide superconducting nanowire single-photon detectors with a direct laser lithography. This patterning method offers a fast and rapid prototyping of devices and can be used for all types of integrated components in lithium niobate. We were able to show a saturated internal detection efficiency for detectors with an unfolded length of up to 4 mm showing the potential for patterning large areas…
We congratulate Felix Dreher who has successfully completed his master thesis titled "Overcoming pyroelectric damage to integrated superconducting detectors on lithium niobate waveguides".
We congratulate Jan Philipp Höpker who successfully defended his PhD thesis titled "Integrated measurement-induced nonlinearity with superconducting detectors" and was awarded the "Dr. rer. nat." degree by the Faculty of Science at Paderborn University.
In our paper, we demonstrate the coldest spontaneous parametric down-conversion (SPDC) experiment that was done so far. We show that SPDC in nonlinear waveguides, which is typically performed under ambient conditions, remains functional when it is operated at about 4 K. We investigate the source performance metrics and the spectral properties of our SPDC source. Our results indicate that cryogenics principally affect the modes which the SPDC…
We congratulate Johanna Biendl who has successfully completed her master's studies titled "3D Lithography of Micro-Structured Etalon Arrays for Single-Photon Spectrometry".
Students from the MINT-EC-Camps visited the university of Paderborn, and the MQO-lab. The focus was on all the lasers being used, and why we need them.
For more information (German)
From November 1st till November 5th was the digital QIM VI conference 2021. The MQO group contributed with a talk from Timon Schapeler. His presentation can be found under the following link.
In our new paper, we demonstrate the integration of amorphous tungsten silicide superconducting nanowire single-photon detectors on titanium in-diffused lithium niobate waveguides. We show proof-of-principle detection of evanescently coupled photons of 1550 nm wavelength using bidirectional waveguide coupling for two orthogonal polarization directions. We investigate the internal detection efficiency as well as detector absorption using…
