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The definition of the ampere, the unit of electric current, in the just revised International System of Units (SI) is based on a fixed value for the elementary charge e. The Joint Research Project (JRP) “e-SI-Amp: quantum realisation of the SI ampere” was launched in the frame of the European metrology research programme EMPIR to develop ways for generating and disseminating electrical current...

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Two-way satellite time and frequency transfer (TWSTFT) is a primary technique for the generation of coordinated universal time (UTC). At present, more than 12 timing laboratories around the world use SAtellite Time and Ranging Equipment (SATRE) modems in TWSTFT operations and contribute data for the realization of UTC. The advantages of TWSTFT are its small calibration uncertainty (≤1.0 ns if the...

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Single-photon sources are set to be a fundamental tool for metrological applications as well as for quantum information related technologies. Because of their upcoming widespread dissemination, the need for their characterization and standardization is becoming of the utmost importance. Here, we illustrate a strategy to provide a quantitative estimate of the multi-photon component of a...

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Bericht über den Stand der pränormativen Aktivitäten in CIE JTC 12 "The measurement of sparkle and graininess" und über neuartige definierte Proben zur Charakterisierung von Messapparaturen und -verfahren.

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We present the concept of a new setup, which combines two different sampling methods to measure the modulation transfer function of camera objectives. The development process with the goal of reaching a measurement uncertainty of 0.01 (k=2) is supported by optical ray tracing simulations in addition to the geometrical modeling of the system.

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Die AG 4.51 Reflexion und Transmission (https://www.ptb.de/cms/ptb/fachabteilungen/abt4/fb-45/ag-451.html) des Fachbereichs 4.5 Angewandte Radiometrie der PTB Braunschweig betreibt im Arbeitsbereich der gerichteten Reflexions- und Transmissionsmessungen eine Referenzapparatur, die einen nominellen Wellenlängenbereich von 200 nm bis maximal 20 m abdeckt. Zur Erzeugung der Messtrahlung oberhalb von...

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Diffuse reflectance measurements in sphere geometries are usually performed using a single photodetector. However measurements of graininess require also spatial resolution, thus they are performed using a radiometric camera attached to the integrating sphere. The usually applied measurement geometry is d:0°. When performing such measurements on glossy samples, the phenomenon of gloss exclusion...

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Sparkle, as defined by ASTM E284 -17 Standard Terminology of Appearance is "the aspect of the appearance of a material that seems to emit or reveal tiny bright points of light that are strikingly brighter than their immediate surround and are made more apparent when a minimum of one of the contributors (observer, specimen, light source) is moved". Since the measurement of this visual texture is...

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The Supplementary Comparison COOMET.PR-S2 was carried out to ensure the correctness and comparability of angle of rotation of plane of polarization measured by the Participants of the comparison within the uncertainties claimed for their measuring facility.
COOMET.PR-S2 was conducted within the Regional Metrology Organization (RMO) "Euro-Asian Cooperation of National Metrological Institutions"...

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Single-photon sources play an important role in several fields of research, e.g. in quantum key distribution and quantum-enhanced measurements. In radiometry, a single-photon source is very favorable, compared to a classical source, as a standard source for the detection efficiency calibration of single-photon detectors. Furthermore, such source is necessary to close the gap between classical and...

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Single-photon sources play an important role in many of the emerging quantum technologies. Beside their implementation in quantum computing and quantum key distribution [1, 2], they are also interesting for the radiometry [1]. Ideally, single-photon sources have neither multi-photon emission nor background emission. Such a source has the potential to become a standard source in radiometry [2]....

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Single-photon sources have a wide field of implementation, e.g. in quantum key distribution, quantum computing, and quantum-enhanced optical measurements. Because of their negligible background and high suppression of multi-photon emission, single-photon sources have the potential to become a standard source in radiometry. Such source is necessary to close the gap between classical and quantum...

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Das Interesse an genauen und rückgeführten Messungen der Modulationstransferfunktion (MTF) von abbildenden Objektiven ist insbesondere für den Einsatz im Automotive-Bereich stark gestiegen. In einem gemeinsamen Projekt der beteiligten Partner soll die metrologische Basis für rückgeführte MTF-Messungen in der Industrie geschaffen werden. Dazu wurde in der Physikalisch-Technischen Bundesanstalt...

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In Wissenschaft und Technik werden vermehrt große optische Flächen eingesetzt, z. B. für astronomische Teleskopspiegel und in der Optik- und Automobilindustrie. Dabei werden auch zunehmend Asphären und Freiformflächen verwendet. Dies schafft einen Bedarf an einer hochgenauen und rückgeführten Formmessung von großen Optiken.
Wir entwickeln ein Konzept für die optische Formmessung an Flächen bis zu...

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The assumption that the reflectance of white diffuse reflectance standards is identical to that of the perfect reflecting diffuser (PRD) allows these standards to be used to characterize reflectance or radiance factors of any surface at any irradiation/collection geometry simply by comparison. However, this assumption is only true within certain limits, and, for some applications, requirements may...

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The uncertainty for photometric responsivity calibrated with the tunable lasers in photometry setup (TULIP) at Physikalisch-Technische Bundesanstalt (PTB) is presented. The measurement and the uncertainty calculation presented were done in preparation for the upcoming new traceability chain for luminous intensity at PTB. Regarding the new traceability a comprehensive uncertainty calculation is...

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In der PTB wurde die Referenzstrahlungsquelle des Hyperspektralsatelliten zur Erdfernerkundung EnMAP im Wellenlängenbereich von 400 nm bis 2500 nm mit hoher Auflösung kalibriert um die langfristige Vergleichbarkeit und Rückführung seiner globalen Messdaten aus dem geobiologischen, ‑chemischen und ‑physikalischen Bereich sicherzustellen.

Das „Environmental Mapping and Analysis Program“ (EnMAP) ist...

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Im Rahmen eines vom Bundesministerium für Wirtschaft und Energie geförderten Projektes haben die PTB und die Xiralite GmbH gemeinsam einen Prototyp für eine Fußkamera zur Früherkennung rheumatischer Erkrankungen an den Zehengelenken aufgebaut. Dieses Gerät wurde im Mai 2019 auf dem User-Meeting der Xiralite GmbH zu rheumatischen Erkrankungen erstmals ...

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