Silicon Trap Detectors Research Articles

High-accuracy room temperature planar absolute radiometer based on vertically aligned carbon nanotubes.

We have developed a planar absolute radiometer for room temperature (PARRoT) that will replace the legacy C-series calorimeter as the free-space continuous-wave laser power detector standard at the National Institute of Standards and Technology (NIST). This instrument will lower the combined relative expanded measurement uncertainty (k = 2) from 0.84 % to 0.13 %. PARRoT's performance was validated by comparing its response against a transfer standard silicon trap detector traceable to NIST's primary standard laser optimized cryogenic radiometer (LOCR) and against the C-series calorimeter. On average, these comparisons agreed to better than 0.008 % and 0.05 %, respectively.

Development of a detector-based absolute spectral power responsivity scale in the spectral range of 300–1600 nm

The radiometry laboratory at the National Institute of Standards (NIS) has taken in his shoulder to develop and improve the spectral responsivity facilities to get high precision and more reliable optical detectors measurements. During the last few years, the calibration of the detectors was refined as well as the reliability of spectral responsivity results, especially in the critical ultra-violet and infrared range of the spectrum. This setup was constructed using a lamp-monochromator-based setup accompanied by a silicon trap detector and an Indium Gallium Arsenide (InGaAs) detector to extend the scale to the infrared (IR) spectral region. Both detectors are traceable and shown to be spatially uniform, linear, stable, and capable of disseminating an absolute spectral responsivity scale. The uncertainty contribution of the spectral responsivity for a silicon-based detector is less than 1–1.9% for the spectral range 300–1100 nm, and about 2–3.8 % (k = 2) for InGaAs-based detector in the wavelength range 800–1600 nm. Additionally, this paper gives a comprehensive overview of’ NIS’s spectral responsivity facilities, which are now fully automated and controlled by LabVIEW.

Room temperature laser power standard using a microfabricated, electrical substitution bolometer.

The design and performance of a room temperature electrical substitution radiometer for use as an absolute standard for measuring continuous-wave laser power over a wide range of wavelengths, beam diameters, and powers are described. The standard achieves an accuracy of 0.46% (k = 2) for powers from 10 mW to 100 mW and 0.83% (k = 2) for powers from 1 mW to 10 mW and can accommodate laser beam diameters (1/e2) up to 11mm and wavelengths from 300nm to 2 μm. At low power levels, the uncertainty is dominated by sensitivity to fluctuations in the thermal environment. The core of the instrument is a planar, silicon microfabricated bolometer with vertically aligned carbon nanotube absorbers, commercial surface mount thermistors, and an integrated heater. Where possible, commercial electronics and components were used. The performance was validated by comparing it to a National Institute of Standards and Technology primary standard through a transfer standard silicon trap detector and by comparing it to the legacy "C-series" standards in operation at the U.S. Air Force Metrology and Calibration Division (AFMETCAL).

Realization of spectral irradiance responsivity at NIS-Egypt

Realization of the absolute spectral irradiance responsivity of photodetectors in A/W/cm2 is a fundamental requirement for many photometric, radiometric and colorimetric applications. This work aimed to develop a standardized radiometric setup for realizing the absolute spectral irradiance responsivity in the range of 500 nm–950 nm at the National Institute of Standards (NIS), Egypt. A silicon trap detector, calibrated against the primary standard cryogenic radiometer, is used as a transfer standard for the calibration of S2281 Hamamatsu silicon photodiode, as a working standard, using a lamp-double monochromator based system. The accompanied uncertainty components affecting the measurements were investigated.

Bilateral comparison of cryogenic radiometers between NPL and UME, linked to the CCPR-S3 supplementary comparison

This report presents the results of a bilateral comparison between NPL and UME, which was carried out to establish the unilateral degrees of equivalence for UME with respect to the defined reference value of the CCPR S3 supplementary comparison of cryogenic radiometers using silicon trap detectors as transfer devices. In accordance with the protocol for the CCPR S3 comparison, UME was asked to calibrate a set of NPL supplied silicon trap transfer detectors at a series of laser wavelengths; UME chose to measure at 514.5 nm and 632.8 nm.Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

溯源至低温辐射计的硅陷阱探测器紫外波段绝对光谱响应度测量

溯源至低温辐射计的硅陷阱探测器紫外波段绝对光谱响应度测量

A Cryogenic Radiometry Based Spectral Responsivity Scale at the National Metrology Centre

This paper describes the spectral responsivity scale established at the National Metrology Centre (NMC) based on cryogenic radiometry. A primary standard – a mechanically pumped cryogenic radiometer together with a set of intensity-stabilised lasers provides traceability for optical power measurement with an uncertainty in the order of 10-4 at 14 discrete wavelengths in the spectral range from 350nm to 800nm. A silicon trap detector, with its absolute responsivity calibrated against the cryogenic radiometer is used as a transfer standard for the calibration of other detectors using a specially built spectral comparator. The relative spectral responsivity of a detector at other wavelengths can be determined through the use of a cavity pyroelectric detector and the extrapolation technique. With this scale, NMC is capable to calibrate the spectral responsivity of different type of photo detectors from 250nm to 1640nm with an uncertainty range from 3.7% to 0.3%.

Final report on the bilateral supplementary comparison of cryogenic radiometers CCPR-S3 between the NPL and the NMC-A*STAR

Following the decisions of the 1994 meeting of the Consultative Committee for Photometry and Radiometry (CCPR), BIPM acted as pilot laboratory for an international comparison of cryogenic radiometers, later designated as a supplementary comparison CCPR-S3, carried out using silicon trap detectors as transfer devices. This comparison was completed in February 1999.After the completion of this comparison and the publication of the final report, the National Metrology Centre of the Agency for Science, Technology and Research (NMC-A*STAR) of Singapore expressed a wish to demonstrate its primary spectral responsivity measurement capabilities, in support of its CMC claims, through linkage to the CCPR-S3 comparison. NPL offered to organize a bilateral comparison with NMC-A*STAR following a similar protocol to that used in the original comparison.The comparison was carried out by using three silicon trap detectors as transfer devices, to be calibrated at a number of laser wavelengths at NPL and NMC-A*STAR from 2005 to 2007.The results of the comparison demonstrate agreement between NMC-A*STAR and CCPR-S3 comparison reference values, in the selected wavelength range, to better than 6.8 parts in 104 with a combined uncertainty (k = 1) of 2.2 parts in 104 or better.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Final report on the bilateral supplementary comparison of cryogenic radiometers CCPR-S3: NPL–CMI

We present results of a bilateral supplementary comparison, between NPL and CMI, of cryogenic radiometers, using silicon trap detectors as the transfer standard. The comparison was based on the technical protocol of the CCPR-S3 comparison (BIPM Report BIPM-2000/9).The results of this comparison demonstrate agreement between CMI and the CCPR-S3 comparison reference values, in the selected wavelength range, to better than 2.7 parts in 104 with a combined standard uncertainty (k = 1) of 2.2 parts per 104 or better.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Spectral irradiance comparison using a multi-wavelength filter radiometer

An automatic multi-wavelength filter radiometer (MWFR) was developed at the National Metrology Centre (NMC) of Singapore to realize the spectral irradiance scale in the wavelength range from 250 nm to 1600 nm. The UV–VIS range (250 nm to 900 nm) is covered by a silicon trap detector with 17 filters, while the near IR range (900 nm to 1600 nm) is covered by an InGaAs photodiode with 7 filters. A complete run of measurements at all 24 wavelength points takes only 12 min. The spectral irradiance scales of NMC and MIKES/TKK (Finland) in the spectral range from 280 nm to 900 nm were compared successfully using this instrument. Measurement results of three standard lamps calculated using MIKES/TKK's algorithm showed excellent repeatability and very good agreement with their assigned values. It is concluded that, compared with the conventional monochromator based spectroradiometers, a properly designed MWFR with sufficient spectral coverage is a good alternative instrument for spectral irradiance comparison owing to its faster speed and better short-term reproducibility.

Radiometer standard for absolute responsivity calibrations from 950 nm to 1650 nm with 0.05% (k = 2) uncertainty

A near-IR radiometer standard with similar performance to silicon trap detectors has been developed to calibrate detectors and radiometers for absolute spectral power, irradiance and radiance responsivities between 950 nm and 1650 nm. The new radiometer standard is utilized at the Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) which is the reference calibration facility of NIST for absolute responsivity. The radiometer standard is a sphere detector with a unique geometrical arrangement and it can convert the radiant power responsivity scale of the primary-standard cryogenic radiometer into a reference irradiance responsivity scale. The 0.05% (k = 2) scale conversion uncertainty is dominated by the two largest uncertainty components of the radiometer: the spatial non-uniformity of responsivity of less than 0.05% in power mode and the 0.03% angular responsivity deviation from the cosine function in a 5° angular range in irradiance mode. These small uncertainty components are the results of a tilted input aperture (relative to the sphere axis) and four symmetrically positioned InGaAs detectors around the incident beam spot in the sphere. With the new radiometer standard, it is expected that a thermodynamic temperature uncertainty of 10 mK (k = 2) can be achieved at 157 °C, the freeze temperature of the In fixed-point blackbody.

Accurate calibration of the spectral responsivity of silicon trap detectors between 350 and 1064 nm

In optical remote sensing, the calibration of remote sensor plays a key role in the quantificational remote sensing. A state-of-the-art highest accuracy standard transfer method is developed, which can transfer the standard cryogenic radiometer to secondary standard trap-type detector, and the absolute spectral responsivity calibration system is set up in the band between the visible to near-infrared in our laboratory. It is required that the process of standard transfer should produce little measurement uncertainty. In this paper a Ti: sapphire tunable laser, doubler and single wavelength laser in 24 interval of wavelengths respectively are used, the spectral responsivity of three silicon trap detectors are calibrated absolutely. The key techniques involved are the accurate positioning and adjustment of the infrared laser and the simulation calibration of window transmittance etc., which have bean successfully resolved. The result shows, in the visible （412nm to 800nm） reqion, the total relative standard uncertainty of the spectral responsivity at the laser lines is less than 0.05%, while in the UV （350nm） and NIR regions above 800nm, the total relative standard uncertainty is less than 0.065%. So the trap detector can be used as a transfer standard detector for calibration of space sensors in the band of 350nm to 1064nm.

Detector based calibration of solar UV radiometers in laboratory environments with high accuracy

A detector based measurement system was designed and established in UME optics laboratory for the calibration of solar UV radiometers. Filter radiometer, made up of a silicon trap detector, band-pass filters and precision aperture in a temperature-controlled enclosure was constructed for this purpose. Spectral responsivity of trap detector was evaluated to be traceable to the cryogenic radiometer and electrically calibrated pyroelectric detector. Uncertainties in the filter radiometer’s responsivities at 291 nm, 296 nm, 313 nm, 357 nm, and 378 nm wavelengths were calculated as 1.6%, 1.3%, 0.8%, 0.6% and 0.2% respectively. Relative uncertainities in irradiance measurements were found to be between 3.4% and 0.9% in the region of 291–378 nm.

Realization of a filter radiometer-based irradiance scale with high accuracy in the region from 286 nm to 901 nm

A technique is introduced for realizing spectral irradiance in the range between 286 nm and 901 nm. The scale is based on a temperature-controlled filter radiometer constructed from a three-element silicon trap detector, band-pass filters and a precision aperture. Seasoned FEL-type quartz halogen lamps are used as reference standards. In this method, direct traceability of the radiometer to the cryogenic radiometer gives an important advantage in the visible and near-infrared regions. Another advantage of this system is the procedure followed for measurement of the distance between the lamp filament and aperture surface of the filter radiometer. The expanded uncertainty (k = 2) of the spectral irradiance measurement is between 2.3% and 1.5% in the UV region, while the uncertainty is of the order of 0.6% above 400 nm.

Absolute calibration of silicon photodiodes by purely relative measurements

Previously verified models of windowless silicon photodiodes can be used to estimate their spectral response by purely relative measurements. The spectral reflectance is found from a single measurement at one wavelength to estimate the oxide thickness, from which the full spectral reflectance is calculated. The internal quantum deficiency of the silicon detector is found by fitting a physical model to a purely relative measurement to a spectrally invariant detector. The detector model ensures correct scaling of the responsivity. This method contributes to simplification of the traceability and promises a very cost efficient realization of an accurate independent spectral response scale. We have measured the responsivity of a silicon trap detector with this method. An uncertainty less than 0.20% was observed with 95% confidence in the spectral range from 455 nm to 760 nm. The uncertainty was calculated from the observed variance in the relative spectral response measurement. The uncertainty was limited by the signal to noise ratio (SNR) in the measurements of the relative spectral response of the silicon trap detectors.

Report on the comparison CCPR-K2.b of spectral responsivity measurements in the range 300 nm to 1000 nm

At its meeting in March 1997, the Consultative Committee for Photometry and Radiometry (CCPR) identified several key comparisons in the field of optical radiation metrology, one of which concerns spectral responsivity. The present report concerns the key comparison CCPR-K2.b, international comparison of spectral responsivity measurements in the wavelength range 300 nm to 1000 nm, piloted by the BIPM.The comparison was carried out through the calibration of a group of transfer detectors, single silicon photodiodes and trap detectors, by the 17 participating national metrology institutes. It was organized in a star form, in two phases with two groups of participants.The report describes in detail the measurements made at the BIPM and summarizes the reports submitted by the participants. A key comparison reference value and degrees of equivalence have been determined from the calibration results.Main text.To reach the main text of this paper, click on Final Report.Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the Mutual Recognition Arrangement (MRA).

Final report on the subsequent bilateral comparison of cryogenic radiometers CCPR-S3 between the BIPM and the IEN

In 1994 the Consultative Committee for Photometry and Radiometry (CCPR) decided to start an international comparison of cryogenic radiometers. The BIPM acted as pilot laboratory. Following the publication of the results of this comparison in 2000, the Istituto Elettrotecnico Nazionale (IEN, Italy) expressed the wish to repeat the comparison. The report describes the results of this subsequent bilateral comparison between the BIPM and the IEN.The comparison was carried out by using silicon trap detectors as transfer instruments, to be calibrated at a number of laser wavelengths at the IEN and the BIPM.The results obtained by the IEN in the subsequent comparison are in much better agreement with the BIPM results than in the previous comparison. The BIPM providing a link to the previous large-scale comparison, this leads also to a considerably better agreement between the IEN and the other participants of the first comparison.Main text.To reach the main text of this paper, click on Final Report.Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by CCPR, according to theprovisions of the Mutual Recognition Arrangement (MRA).

Advanced comparator method for measuring ultra-small apertureareas

An advanced method is presented, which allows the measurement ofaperture areas with diameters smaller than 50 µm. The method follows thecomparator technique and compares the photocurrent of a detector covered witha reference aperture of known area with the photocurrent of the same detectorequipped with the aperture under investigation. Using typical referenceapertures with diameters of some millimetres, the very small measured aperturearea results in extreme large ratios of measured photocurrents. This requiressophisticated detector and measurement electronics to obtain high accuracy.Significant improvement with respect to common set-ups has been achieved byapplying a silicon trap detector instead of a single photodiode. The advancedset-up allows areas with diameter below 50 µm to be measured withuncertainties in the order of 10-3. Application of the method to fourultra-small apertures with nominal diameters in the range from 300 µm downto 50 µm is presented.

Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer

The Physikalisch-Technische Bundesanstalt has further improved and extended its spectral responsivity scale based on the laser-operated radiation thermometry cryogenic radiometer. Five laser wavelengths in the ultraviolet (UV) (238 nm to 400 nm) and another fifteen in the visible and near-infrared (NIR) (400 nm to 1015 nm) almost cover the entire spectral range where silicon photodiodes can be used in air. The lasers employed are a Kr+ laser, an Ar+ laser with optional intra-cavity frequency-doubling, and a continuously tuneable Ti:sapphire ring laser. The total relative standard uncertainty of the spectral responsivity at the laser lines is u = 10-4 in the visible and NIR below 950 nm and u = 10-3 in the UV. With an improved model for interpolation between the laser wavelengths, a continuous scale of spectral responsivity has been established in the wavelength range 400 nm to 1015 nm.

Interpolation of the spectral responsivity of silicon photodetectors in the near ultraviolet

We improve the methods used to interpolate the responsivity of unbiased silicon photodetectors in the near-ultraviolet region. This improvement is achieved by the derivation of an interpolation function for the quantum yield of silicon and by consideration of this function in the interpolation of the internal quantum efficiency of photodiodes. The calculated quantum-yield and spectral-responsivity values are compared with measurement results obtained by the study of a silicon trap detector and with values reported by other research groups. The comparisons show agreement with a standard deviation of 0.4% between our measured and modeled values for both the quantum yield and the spectral responsivity within the wavelength region from 260 to 400 nm. The proposed methods thus extend the predictability of the spectral responsivity of silicon photodetectors to the wavelength region from 260 to 950 nm. Furthermore, an explanation is proposed for the change in the spectral responsivity of silicon photodiodes that is due to UV radiation. In our improved quantum efficiency model the spectral change can be accounted for completely by the adjustment of just one parameter, i.e., the collection efficiency near the SiO(2)/Si interface.