The paper describes the comparison method and analyses the results of comparison in terms of agreement between the blackbody of the National Physical Laboratory (NPL), United Kingdom and four different blackbody cavities of the Laboratory of Metrology and Quality (LMK), at the University of Ljubljana, Faculty of Electrical Engineering (FE), Slovenia. Three cavity shapes are suggested in different standards as suitable for calibration of infrared ear thermometers (IRETs), while one cavity shape was proposed by the LMK. The agreement between blackbody cavities was determined with the help of platinum resistance thermometers. Two reference IRETs were used to check their stability and level of agreement between calibration results at different institutes and against different blackbody cavities. Measurements were performed with two IRETs, at the NPL in one cavity and at the LMK in four different cavities. The comparison was initiated to solve the problem of assuring proper traceability for IRETs and to present the solution to their users.
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http://dx.doi.org/10.1088/0967-3334/25/5/013 | DOI Listing |
Entropy (Basel)
June 2024
Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy.
The modern textbook analysis of the thermal state of photons inside a three-dimensional reflective cavity is based on the three quantum numbers that characterize photon's energy eigenvalues coming out when the boundary conditions are imposed. The crucial passage from the quantum numbers to the continuous frequency is operated by introducing a three-dimensional continuous version of the three discrete quantum numbers, which leads to the energy spectral density and to the entropy spectral density. This standard analysis obscures the role of the multiplicity of energy eigenvalues associated to the same eigenfrequency.
View Article and Find Full Text PDFEfficient coupling in broad wavelength range is desirable for wide-spectrum infrared light detection, yet this is a challenge for intersubband transition in semiconductor quantum wells (QWs). High-Q cavities mostly intensify the absorption at peak wavelengths but with shrinking bandwidth. Here, we propose a novel approach to expand the operating spectral range of the Quantum Well Infrared Photodetectors (QWIPs).
View Article and Find Full Text PDFPhys Chem Chem Phys
June 2023
Department of Chemistry, Memorial University, St. John's, NL, A1B 3X7, Canada.
Protonated complexes composed of a basket-like host molecule 1,1,,-tetramethyl[](2,11)teropyrenophanes (TMnTP) ( = 7, 8, 9) and glycine as a guest were studied in the gas phase by experimental and computational methods. Blackbody infrared radiative dissociation (BIRD) experiments of [(TMnTP)(Gly)]H not only provided the observed Arrhenius parameters (activation energies, obsa, and frequency factors, A) but also suggested the existence of two populations of isomeric complexes of [(TMnTP)(Gly)]H, termed fast dissociating (FD) and slow dissociating (SD), due to their relative BIRD rate constants. Master equation modeling was conducted to obtain the threshold dissociation energies of the host-guest complexes.
View Article and Find Full Text PDFMacromol Rapid Commun
August 2023
School of Chemistry and Biochemistry, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Shortwave infrared (SWIR, λ = 1-3 µm) photodetectors typically use compound semiconductors that are fabricated using high-temperature epitaxial growth and require active cooling. New technologies that overcome these constraints are the focus of intensive current research. Herein, oxidative chemical vapor deposition (oCVD) is used for the first time to create a room temperature, vapor-phase deposited SWIR photoconductive detector with a unique tangled wire film morphology that detects nW-level photons emitted from a 500 °C cavity blackbody radiator-a rarity for polymer systems.
View Article and Find Full Text PDFSci Rep
March 2023
Electrical and Computer Engineering Department, University of Missouri Columbia, Columbia, MO, USA.
We have investigated an uncooled infrared (IR) detector utilizing a dual level architecture. This was achieved by combining two-microbolometer stack in the vertical direction to achieve high IR absorption over two distinct spectral windows across the long wavelength infrared region (LWIR). In addition, we have studied amorphous silicon germanium oxide (SiGeO) as an IR sensitive material, and metasurface to control IR absorption/reflection in interaction with standard Fabry-Perot cavity.
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