Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Full posters in pdf format have been uploaded to our mobile/desktop conference app. For those who provided an optional short summary of the posters, please see below. 

Brian Alberding

A Pyroelectric Detector-Based Method for low uncertainty irradiance and radiance calibrations in the short-wave infrared using tunable lasers

Pyroelectric detectors offer low uncertainty ( 0.5%) irradiance responsivity calibrations in the Short-wave Infrared (SWIR) by measurement of the pyroelectric detector hemispherical reflectance and direct irradiance responsivity calibration at tie point wavelengths against highly uniform silicon tunnel trap detectors without lock-in amplification.

Uwe Arp


We report the successful realization of the ultraviolet spectral responsivity scale in the wavelength range between 200 nm and 400 nm at 5 nm intervals with a combined relative standard uncertainty below 0.5 % (k=1). This scale realization was based on a laser-driven light source and an absolute-cryogenic radiometer.

Alexandra Artusio-Glimpse

Validation of a compact radiation pressure power meter at hundreds of watts

Our small package, radiation pressure power meter is attractive for real-time, high-accuracy power measurements in laser material processing applications. We report measurement validations of this device at 1070 nm from 25 W to 400 W with 3.1-4.6 % expanded uncertainty.

Robin Aschan

CCPR-K5.2019 Key Comparison of Spectral Diffuse Reflectance

The CCPR-K5.2019 Key Comparison measurements have started with MIKES-Aalto as the pilot laboratory. We measure the average spectral diffuse reflectance of two types of samples using a gonioreflectometer. In the short term, the reflectance of the samples is stable and uniform from the surface central area of 30 mm in diameter.

Janne Askola


Effect of nitrogen flow purging on the trap detector responsivity, up to 0.8%, is presented with methods to minimize it down to zero.

In-Ho Bae

Performance evaluation of a thermoelectrically-cooled SiC single photon avalanche photodiode

In this paper, we report on the characteristics of a lab-assembled UV single photon avalanche photodiode (SPAD) based on a thermoelectrically cooled silicon carbide (4H-SiC) avalanche photodiode (APD).

Eivind Bardalen

Packaging of silicon photodiodes for use as electrical substitution radiometer

The dual mode detector (DMD) combines the Predictable Quantum Efficient Detector (PQED) and the electric substitution radiometer (ESR). Thermal simulations in COMSOL were performed to design and predict the DMD thermal response in the range 40 K to 290 K.

Steven Brown

Dynamic Synthetic Calibration Source Distributions for Reduction of Out-of-Band Measurement Errors in Multi-band instruments

An algorithm to reduce multi-band sensor measurement errors due to finite out-of-band (OOB) response is described using a dynamic, measurement-dependent synthetic calibration source distribution, itself relying on a detector-based calibration of an instrument.

Cheng-Hsien Chen

On-Site Measurements of Reflection Characteristics of a Dry Asphalt Road

On-site measurements of luminance images as well as illuminance distribution for the studies of reflected properties of a LED lighted dry asphalt road have been performed.

Justus Christinck

Comparison of back focal plane imaging of nitrogen vacancy centers in nanodiamond and core-shell CdSe/CdS quantum dots

We report on the characterization of the angular-dependent emission of two different single-photon emitters based on nitrogen-vacancy centers in nanodiamond and core-shell CdSe/CdS quantum dot nanoparticles.

Catherine Cooksey

Improvements to the Ultraviolet Measurement Capabilities of RTS

We report on recent improvements to performance of NIST’s Reference Transmittance Spectrophotometer (RTS) in the ultraviolet (UV) and visible spectral range. The improvements include the installation of a new UV source for increased spectral radiance and a monitor line for reduced signal-to-noise ratio.

Jimmy Dubard

Characterisation of high irradiance level 254 nm UV sources for UVmeter calibration

UVC light around 254 nm is used in many applications that requires high irradiance levels up to 150 W/m².  We present the results of our work to set-up capabilities for the calibration of UVC radiometer. Low-pressure mercury lamps with amalgam as well as newly developed UVC LED show good performances for that purpose.

Guojin Feng

Design and Evaluation of Extremely LowReflectance Measurement Device

The demand for ultra-low reflectance measurement is increasing. A set of diffuse reflectance measurement system with a wavelength range of 500nm~2000nm under the condition of 0/d is built, the measurement range is 0.0001~1, and the worst relative uncertainty is less than 10% (k = 2).

Thiago Ferreira da Silva

Optical frequency metrology based on photon counting

Low power can be a concern for traditional calibration of frequency-stabilized laser sources against a reference using heterodyne beating technique. Here is presented a calibration method for extremely low power sources based on correlated photon counts in a Hong-Ou-Mandel interferometer. Uncertainty budget is developed and results are validated.

Intercomparison of indoor and outdoor spectral irradiance measurements between INTI and INMETRO

National metrology institutes of Argentina (INTI) and Brazil (INMETRO) developed their spectral irradiance calibration systems traced to reference lamps and then performed intercomparison of calibrated lamps between 250 nm and 1100 nm and of spectroradiometers for solar UV measurements.

Alejandro Ferrero

Recommendation for finite intervals in BRDF measurements of glossy samples

Recommendations on the finite intervals of irradiation and collection solid angles for measuring the Bidirectional Reflectance Distribution Function of highly glossy samples, close to the specular direction, are derived from high angular resolution measurements carried out with the conoscopic system at CNAM, specially designed for measuring gloss.

Angela Gamouras

Advancements in NRC’s Primary Spectral Irradiance Scale Realization

The primary spectral irradiance scale at the National Research Council Canada has transitioned to a detector and source-based realization from 250 nm to 2500 nm. A high temperature blackbody is now the primary light source for the calibration of FEL standard lamps. The facility, measurement procedure and uncertainty contributions will be presented.

Jinhwa Gene

Systematic errors that depend on diffusivity and absorptance of sample in IEC method for absolute photoluminescence quantum efficiency

We studied systematic errors of IEC method for PLQE with Monte-Carlo ray-tracing simulation. From the calculation, we showed that systematic errors of the IEC method strongly depend on diffusivity and absorptance of sample under the test. Then, we suggested and demonstrated correction method for that.

Georgi Georgiev


This paper describes the initial work of characterizing the transmissive and reflective properties of Black Silicon (Si) diffusers. BRDF and BTDF of a Black Si sample were measured at 632.8nm, 1064nm, and 1550nm. The diffuser exhibits extremely low specular reflection up to ~1100nm. There is no evidence of retroscatter.

Thorsten Gerloff

Lichtstärkenormal auf LED-Basis

Source-based radiometric calibrations are mainly based on the use of incandescent lamps.In our poster we discuss the advantages and disadvantages of a radiometric standard based on LEDs. The LED source presented here has a very high reproducibility and is suitable for the calibration of radiometric detectors in the visible spectral range.

Wesley Gilliam

Measurement of Far-Ultraviolet Transmission in Hollow-Core Optical Fibers

We have shown that hollow-core anti-resonant fibers (UV-HCF) can guide light down to ~122 nm, with sufficient throughput to be useful in a wide range of applications. This shatters the current limit for UV fibers, of ~185nm. We showcase the fiber design, testing apparatus, future applications, and performance of the UV-HCF.

Kenji Godo

Development of illuminance meter calibration system with LED spectrally tunable light source

Illuminance meters are usually calibrated using a standard lamp that realizes a spectrum of the CIE standard Illuminant A (Illuminant A). To replace standard lamp method, we constructed an illuminance meter calibration system based on an LED based spectrally tunable light source.

Alexander Gottwald

Recent status of PTB facilities for VUV/EUV detector-based radiometric scale comparison

At the Metrology Light Source (MLS) of the PTB the radiometric scale in the   VUV and EUV spectral range is realized by electrical subsitution radiometers as primary standard. Currently, a new monochromator as well as a new radiometer is under construction. However, currently suitable transfer detectors are lacking.

Jeanne Houston

UV spectral irradiance responsivity calibrations using a scanning method in a monochromator-based facility

The NIST Visible/NIR Spectral Comparator Facility (VisSCF) is a monochromator-based calibration facility designed for measurements of spectral power responsivity (ASR), [A/W] with the beam underfilling the active area.  A beam focused to 1mm2 used to measure the ASR is raster scanned across the aperture and active area of the detector/filter radiom.

Gregor Hülsen

Angular responsivity of ground and space-based direct solar irradiance radiometers

The angular responsivities of 2 radiometers for satellites (JTSIM-DARA on FY-3E and DARA on Proba-3) and one precision filter radiometer (PFR F-064) was measured in at PMOD/WRC using a new 2-axis goniometer setup. The offsets of the pointing of JTSIM-DARA and the DARA pointing could by determined. The full field of view of the PFR was measured.

Mykola Huriev


For assuring the traceability of luminous flux measurements for “white” LEDs, NSC “Institute of Metrology” (Ukraine) has developed prototypes of a reference lamp and a directional radiation source that uses an incandescent lamp with correction filters. The spectrum of the developed sources corresponds to the LED spectrum.

Jeongwan Jin

Establishment of single-photon detector efficiency calibration system at NRC

National Research Council (NRC) of Canada has established a free space single-photon detector efficiency measurement system. Measured efficiencies, of a silicon single-photon avalanche diode, are SI-traceable through the NRC optical power scale. Comparison measurements of the SPAD are performed at the National Institute of Standards and Technology.

Carol Johnson

Thermal Characterization of Fiber-Coupled Spectrographs

Accurate spectral radiometry utilizing spectrographs requires thorough instrument characterization. The performance of spectrographs with silicon photo-diode or CCD arrays demands increased scrutiny as applications continue to push for lower uncertainties and incandescent lamp sources are being replaced by non-Planckian radiators. .

Boris Khlevnoy

High-Temperature Fixed-Point Blackbody with Temperature of about 2856 K Based on Melting Phase Transition of δ(MoC)-C

Large-area HTFP blackbody of δ(MoC)-C type with temperature of about 2856 K has been developed. The δ(MoC)-C HTFP has been investigated using several δ(MoC)-C cells of different sizes. Thermodynamic temperature of the δ(MoC)-C fixed point (POI) has been determined equals to 2856.93 K with standard uncertainty of 0.35 K.

Mikhail Korpusenko

Quantum efficiency of Predictable Quantum Efficient Detector in the ultraviolet region

An experimental optical system of two laser sources and a silicon photodetector was built to test the double laser radiometry technique. The goal is to achieve a nonlinear region in silicon photodiodes and deactivate surface recombination centers. We observe the present limit of performance of the measurement system at the level of 0.08%.

Ozhan Koybasi

Investigation of surface passivation thin film materials for improved predictable quantum efficient detectors

We present our work on optimization of surface passivation of inversion-layer silicon photodiodes to reduce the internal quantum deficiency of Predictable Quantum Efficient Detectors (PQED) to fulfil the increasing measurement accuracy needs of National Metrology Institutes (NMIs).

Stefan Kück

The SIQUST-project – towards single‐photon sources as new quantum standards

In this poster presentation, the EURAMET joint research project “Single-photon sources as new quantum standards” (SIQUST,, funded within the European Union Horizon 2020 research and innovation programme, will be presented. The focus will be on the development of single‐photon sources towards new quantum standards.

Dmitri Lanevski

Gonioreflectometric properties of the sand from RadCalNet Gobabeb test site

Gobabeb test site is one of the instrumented semi-invariant locations on Earth that is used for vicarious post-launch calibration of satellite optical sensors. For this reason a sample of sand from Gobabeb test site was collected and measured in a laboratory using a 3D goniometer. Data are compared to on-site measurements.

Determining the shape of reflectance reference samples for curved surface reflectors

Current work presents a method to determine a shape of the new reflectance reference sample that by its reflectance properties would be similar to actual insulation materials and that could be manufactured by precise additive manufacturing or by some other method. Method’s performance is validated using Monte-Carlo simulations.

Sun Do Lim

Primary and working standards for spectral total reflectance in Mid-IR region in KRISS

We present a primary standard for spectral total reflectance in Mid-IR region in KRISS, which is based on the 3rd Taylor method with 8°/d geometry. We also introduce a working standard based on a comparison method using a reflectance reference that is calibrated with our primary standard.

Maritoni Litorja

Preliminary Work on Calibration of Dim Light Sources

Abstract. Light sources with radiant flux at femtowatt to nanowatt power is needed to calibrate sensitive cameras used for biomedical imaging.  We employ a system to calibrate these dim sources by using a light source split by a high ratio (e.g.,90:10) bifurcated optical fiber. The measured split ratio along with the calibration of the high output.

Wen-Chun Liu

Transmittance Haze Measurement by DIN 5036 Part 3

This paper presents the analysis and results of transmittance haze by using DIN 5036 part 3. From the simulation, diffuse transmittance is strongly dependent on reflectance of the integrating sphere, which also makes transmittance haze deeply affected.

Khaled Mahmoud

New Laser-Driven Light Source (LDLS)-based DSR measurement facility for calibration of reference PV cells

This novel DSR technique realized to measure the spectral responsivity in the range from 250 nm to 2000 nm, bias level up to 1.5 kW/m2, with intense AC monochromatic signal with target uncertainty below 1%(k=2, visible range) can be achieve.

Peter Meindl

Realization and Dissemination of the Spectral Responsivity of Thermal Detectors in the Mid-Infrared Spectral Range at the PTB

The PTB expanded its capabilities of the SI traceable absolute measurement of radiant power into the spectral range of the MIR by implementing additional laser radiation sources at one of PTB´s cryogenic electrical substitution radiometer facilities. This extension enables absolute calibrations of the spectral responsivity of detectors in the MIR.

Haifeng Meng

Measurements of monolithic GaInP2/InGaAs/Ge triple-junction solar cells

Benefit from the three sub-cells, that is GaInP2, InGaAs and Ge sub-cell,  monolithic GaInP2/InGaAs/Ge triple-junction solar cells can make use of solar irradiance in the wavelength range of 300 nm to 1800 nm, so that achieve high efficiency. They have become the main energy source for space on-orbit applications, and should be assembled into space

Cameron Miller

Development of UVC Measurement Tools at NIST to Combat Healthcare-Associated Infections (HAIs)

The adoption of UV-C technology by the healthcare industry has been sporadic largely due to the lack of measures for products and efficacy. NIST has leveraged our new UV scale realizations to provide multiple calibration facilities for a variety of source technologies allowing us to support documentary standards development.

Yuri Nakazawa

Comparison of Two Methods for Total Luminous Flux Measurement of White LEDs

Total luminous flux of commercial white LEDs measured with the sphere-spectroradiometer in 2pi geometry were smaller than that measured with the goniophotometer by 1% to 5%. Near-field absorption and spatial response distribution function of an integrating sphere were estimated as main uncertainty factors of this difference.

Yuri Nakazawa

Comparison of Two Methods for Total Luminous Flux Measurement of White LEDs

Total luminous flux of commercial white LEDs measured with the sphere-spectroradiometer in 2pi geometry were smaller than that measured with the goniophotometer by 1% to 5%. Near-field absorption and spatial response distribution function of an integrating sphere were estimated as main uncertainty factors of this difference.

Siarhey Nikanenka


In 2019, a National standard of Belarus of the units of radiant intensity, spectral radiance and irradiance in the wavelengths range from 0.2 μm to 3.0 μm was created. This report describes the details of a spectral irradiance and radiance facilities of the standard.


A compact reference UVC source based on state-of-the-art commercially available LED has been developed at B.I. Stepanov Institute of Physics NAS of Belarus. The paper presents the design and results of the study of the optical characteristics of the radiation of the reference UVC LED source.

Marit Ulset Nordsveen

Simultaneous optical and electrical heating in dual-mode photodiode operation at room temperature

The dual-mode optical power detector combines thermal and photoelectrical detection, and achieves a type A relative uncertainty of less than 100 ppm at room temperature. This work shows the comparison of two different methods of electrical substitution in thermal mode, where optical heating is done with and without simultaneous electrical heating.

Yoshi Ohno

Global Interlaboratory Comparison of 42 Goniophotometers Measuring Solid-State Lighting Products

The world’s largest interlaboratory comparison of measurement of solid state lighting products using goniophotometers was conducted under the International Energy Agency (IEA) 4E SSL Annex. With 36 labs participating from 19 countries, IC 2017 involved a total of 42 goniophotometers. The technical protocol and some results are presented.

Heather Patrick

ROSI: the new NIST reference facility for UV-SWIR specular and diffuse reflectance calibrations

ROSI: the new NIST reference facility for UV-SWIR specular and diffuse reflectance calibrations describes the design, uncertainty budget, and validation of the US national reference instrument for specular and bidirectional diffuse reflectance measurements at UV-SWIR (250 nm to 2400 nm) wavelengths.

Tobias Pohl

Absolute Calibration of the Spectral Responsivity of Thermal Detectors at a High-Temperature Blackbody at the PTB

The Physikalisch-Technische Bundesanstalt (PTB) has set up a primary method for the SI traceable calibration of the spectral responsivity of thermal detectors in the near- and mid-infrared spectral range. This method uses the calculable radiation of a blackbody radiator and optical bandpass filters.

Tatjana Quast

Polarization effects in diffuse reflection measurements at the transition between the UVA and VIS spectral range

Polarization effects play an important role in diffuse reflection measurements. Even for matte, quasi-Lambertian reflection samples, a large degree of polarization can be induced by reflection in certain bidirectional geometries. This effect has been studied at the transition between the UV-A and VIS spectral range using a new LED-based radiator.

Terubumi Saito

Complete Polarization Characterization of LEDs by Stokes Parameters Measurements

Stokes parameters have been measured for each color of bullet-shaped RGB-type LED at 3 different directions of 0 °, 45° and 90° from the principal axis. The hypotheses that geometrical asymmetry generates polarization is experimentally supported.

Conversion Efficiency Measurements for Optical Devices Based on Electrical Substitution Method

Conversion efficiencies of optical devices, both sources and receivers have been measured based on a calorimetric method or electrical substitution method. To automatize the electrical substitution, a constant temperature control is adopted.

Irina Santourian

Development, implementation and validation of a high-power LED-based radiation source for goniometric spectral radiance factor measurements

To improve the accuracy in spectral radiance factor measurements with the robot-based gonioreflectometer at PTB an LED sphere radiation source (LED-SR) was constructed as additional radiation sources in the short-wavelength visible spectral range. Its performance is presented compared to the currently used halogen sphere radiator (Halogen-SR).

Richard Savage

Displacement fiducials for gravitational-wave detectors with sub-percent accuracy using laser power sensors calibrated at NIST

This poster describes the process used to transfer laser power calibration from NIST to the power sensors of Photon Calibrator systems generating displacement fiducials for interferometric gravitational wave detectors.  During LIGO's recent observing run generation of fiducial displacements on order 1e-17 m with 0.4 % 1-sigma accuracy was achieved.

Philipp Schneider

Calibration of a modular trap detector system towards a new realization of the luminous intensity unit

A new kind of realization for the unit of luminous intensity at PTB has been completed for the first time. The results of the calibration steps and the occurring correlations are presented.

Ping-Shine Shaw

NIST’s primary optical power responsivity scale using a supercontinuum source with automation from 480 nm to 1650 nm

In addition to using tunable lasers for detector power responsivity calibration against ACR, we introduce a system based on the supercontinuum source. Unlike lasers, this system is fully automated which significantly shortens the measurement time. Typical uncertainty of 0.04% (k=1) in the visible is comparable to those achieved with lasers.

Gordon Shaw

Comparison of electrostatic and photon pressure small force references

A metrological comparison between electrostatic and photon pressure force was carried out. The comparison establishes the compatibility between an electrostatic force balance measuring nanonewton-level forces and a reference photodetector measuring watt-level laser power within the 5 % uncertainty in the measurement.

Dong-Joo Shin

Power and wavelength-meter in one for lasers and other narrow-band light sources based on the dual-photodiode radiometer concept

We are developing a radiometer, which can simultaneously measure radiant power and centroid wavelength of narrow-band light sources in a wavelength range from 400 nm to 900 nm. The device consists of an integrating sphere and two photodiodes attached on that. The accuracy of the power and wavelength measurements using this device is being tested.

Hiroshi Shitomi

A novel optical diffuser with potentially higher spectral flatness in the near infrared region

We have reported a new optical diffuser, Al2O3 diffuser processed with plasma powder spraying, that has more spectrally neutral than existing optical diffusers in the near infrared region with reduced absorption structure. Basic optical properties of the plasma-sprayed Al2O3 diffuser and its advantage for spectrophotometry has been discussed.

Iurii Sild

Enhancement of the state primary standard of the unit of total radiance.

The State primary standard of the total radiance unit, which was approved in 2018, is described. Within the framework of enhancementnew, blackbodies source were developed ore modernized.The range of the total radiance reproduced by the standard is 54,36 - 61000 W/(sr×m2) with the expanded uncertainty not more than 0,0015 relative units.

Meelis-Mait Sildoja

High-efficiency five-element trap detector with low optical losses

We have constructed a 5-element trap detector using commercially available n-on-p UVG100 photodiodes. The detector has close to 100% internal quantum efficiency from 360 nm to 660 nm and is considered as a cheaper and simpler alternative to the custom-made Predictable Quantum Efficient Detector for use in photometric and radiometric applications.

Peter Sperfeld

Spectral Mismatch Correction for the Calibration of UVA Radiometers

Examples of the calibration of UVA radiometers are used to discuss the possible influence of spectral mismatch due to improperly adapted spectral responsivity of radiometers.

Matthew Spidell

Comparison of NIST - PTB Laser Power Standards for Gravitational Wave Observatory Confidence

The Gravitational Wave observatories calibrate interferometer displacement using photon momentum. Confidence in the scale realization for optical radiant flux (i.e. laser power) is required for confidence in gravitational wave source parameters such as distance and sky location. We undertook a bilateral comparison of NIST-PTB at 1047 nm 100-300 mW.

Qing Sun

High Precision Measurement of Terahertz Frequency Based on Frequency Comb

A terahertz frequency comb is built by using a femtosecond fiber laser and a fiber-coupled terahertz photoconductive antenna. The absolute frequency of terahertz test source is measured with a measurement uncertainty of 3.2E-11. A method for terahertz frequency measurement by using unstabilized femtosecond laser is also introduced.

Minoru Tanabe

Absolute irradiance responsivity calibration system using diode lasers for tricolor laser applications

An absolute irradiance responsivity calibration system with laser light sources at three wavelengths is presented. This system is based on an optical detector with a silicon photodiode and a uniform light source combined with an integrating sphere. The expanded uncertainty of the absolute irradiance responsivity has been analysed to be 0.55–0.57%.

Li-Lin Tay

Raman Analysis of Black-Carbon from Aviation Sources

This poster will cover two topics. The first part will cover Raman spectral analysis of Black Carbon nanoparticles from aviation engine and laboratory generated surrogates. The second part of the poster will cover optical properties of plasmonic nanocavities and its application in sensing and light-matter interactions.

Trinh Tran

PQED response independently predicted over wide spectral range with 3D model based on measurements at one wavelength only

The predictable quantum efficient detector (PQED) is accepted as a new primary standard for radiant power measurement due to its low loss and predictable response. This work develops a 3D simulation model and predicts PQED response independently over a wide spectral range based on measurements at one wavelength only.

CM Tsui

Interpolation of Spectral Responsivity of Trap Detectors and Evaluation of Measurement Uncertainties Using Monte Carlo Method

This poster describes how the Standards and Calibration Laboratory interpolates the responsivity of trap detectors measured by a cryogenic radiometer at 7 wavelengths to the spectral range 400 nm to 800 nm and evaluates the uncertainties using Monte Carlo method.

Damian Twerenbold

Novel Integrating Sphere Based Attenuation Method for Single Photon Detector Calibrations

We propose a novel method where an integrating sphere is used as the second attenuator in the detection substitution technique for determining the detection efficiency of Si SPAD detectors.

Mai Huong Valin

New spectral irradiance traceability scale at LNE-CNAM

The LNE-CNAM developed a new spectral irradiance measurement facility based on the radiometric reference from 250 nm to 2500 nm. This facility extends our measurement capacity up to 250 nm and reduces our measurement uncertainties over almost the entire range. This poster shows our new traceability scheme, the method used, and its validation.

Robert Vest

A New Facility for Deuterium Lamp Calibrations at SURF III

A new facility for the irradiance calibration of deuterium lamps has been constructed and commissioned at the Synchrotron Ultraviolet Radiation Facility (SURF III) at NIST’s Gaithersburg, MD campus. This facility enables the calibration of the irradiance from a lamp under test against the primary standard of irradiance from the NIST synchrotron in the spectral range from 200 nm to 400 nm and longer wavelengths. The uncertainty achieved is on the order of 1% throughout this spectral range.


Lutz Werner

Quantum Yield in Induced Junction Silicon Photodiodes at Wavelengths around 400 nm

The quantum yield in induced junction photodiodes has been measured. The results show that the quantum yield can be larger than unity at wavelengths longer than 400 nm. This observation has to be considered when applying spectral responsivity models which usually assume a quantum yield of exactly unity.

Malcolm White

Optical Fibre Beam Splitter Ratios Are Hard To Measure Accurately

We have investigated the performance of several fibre beam-splitters to fully understand their contribution to the uncertainty of radiometric measurements. The temperature dependence of the polarisation dependent loss was evaluated for fused biconical and planar beam-splitters at 1310 nm and 1550 nm over the range 10 ºC to 40 ºC.

Refractive Index of Optical Fibres Decreases with Temperature

We have measured the temperature dependent Fresnel reflection loss and Rayleigh backscatter of single-mode SMF-28 fibre, polarisation maintaining single-mode fibre and PM photonic crystal fibre. We show that the relative effective refractive index of these fibres reduces by 0.11 %, 0.15 % and 0.30 % respectively from room temperature to 5 K.

Emma Woolliams

SI Traceability, Uncertainty Analysis and Comparison for RadCalNet

RadCalNet is a network of currently 5 desert sites where permanent instruments measure the reflectance of the ground and the transmission of the atmosphere for comparison to satellite instruments. NPL has supported the establishment of RadCalNet and this poster shows the different activities we have done.

The European Metrology Network for Climate and Ocean Observation: A review of Earth observation needs for metrology

The European Metrology Network for Climate and Ocean Observation is a formal structure within EURAMET (the European Association of National Metrology Institutes). The network seeks to coordinate European efforts to bring metrology into climate observations and oceanography and to improve collaborations with stakeholders.

Zhifeng Wu

Low Light Level Realization at Near Correlated Color Temperature

The spectral variation of an integrating sphere lamp shows that the stray light reflected by the aperture and the lamp cavity surface contributes  a lot to the red region with the decrease of the aperture. In order to realize a nearly constant CCT, another integrating sphere is used and the diameter of the aperture should be set a lower limit.

Jae-Keun Yoo

Performance Evaluation of a Mid-infrared Spectrometer for Remote Sensing Applications

We present the development of performance evaluation technologies for mid-IR spectrometers using continuous-wave (cw) optical parametric oscillator (OPO) and laser diodes. We evaluated performance of the mid-IR spectrometer from 2.0 μm to 4.0 μm by using wavelength-tunable light sources.

Howard Yoon

Nonlinearity corrections of spectrographs using combinatorial methods

Signal or gray-level linearities of spectrographs have been determined using a dual-path combinatorial method. Spectrographs were characterized for both signal and count-rate nonlinearities using the NIST beamconjoiner apparatus.

Weiqiang Zhao

Experimental Correction of Temperature Dependence for LED Filament Lamps

Experimental correction model of temperature dependence for LED filament lamps is reported. The quantities approximate relations of the ambient temperature, the voltage and the flux are analysed. With correction, the experimental results show that the flux fluctuation of the LED filament lamp is less than 0.03% without any thermal control.

Created March 5, 2021, Updated June 24, 2021