To meet the growing need for calibrated detector at long-infrared wavelengths, we are reporting on a laser-based absolute spectral responsivity scale of the detector in the long-infrared spectral region. The high-accuracy cryogenic radiometer (HACR) is a cryogenic electrical substitution radiometer that serves as a primary standard for optical power measurements. We measured the transfer standard HgCdTe/sphere detectors at 9.28μm, 9.62μm, 10.26μm and 10.60μm, respectively. The experimental results show that the extended uncertainty of optical power measurement was less than 0.30%~0.42% (k = 2); The extended uncertainty of the absolute spectral responsivity measurement has been analyzed to be 0.80%~1.02% (k = 2).
The detection efficiency calibration of single-photon avalanche detectors is presented. The detection efficiency is determined from the measurement of the photon count rate and incoming photon flux traceable to reference standard detectors, and corrected by afterpulse probability and dead time. We describe the measurement facilities and the reference standard detectors used, as well as the traceability chain of the measurements to the primary standard detector. As an example, the measurement uncertainty components are determined and analyzed in detail and the obtained combined standard measurement uncertainty is <0.5% at 633nm and 1550nm.
The “quantum” system of optical radiation metrology based on spontaneous parametric down-conversion (SPDC) correlated photon sources and coincidence measurement technology has important applications in the field of extremely weak optical radiation detection. To acquire widely tunable entangled photon sources, 532 nm continuous laser was used to pump periodically poled LiNbO3 (PPLN) crystal. And 676 nm~2500 nm correlated photons were got by switching the crystal period and tuning the temperature. Firstly, the parameters such as polarization period, length and temperature control precision of PPLN crystal were made a theoretical study. Thus, the polarization period of PPLN crystals, the bandwidth distribution curve of the signal light in different wavelength, and temperature control precision curve of the different wavelength of signal light are further calculated. The results show that, the 676 nm~2500 nm correlated photon can be got by using 9 PPLN crystals in the temperature range of 50°C~200°C. The bandwidth of the signal light has negative correlation with the crystal length; The temperature control precision of PPLN crystals was from 3.96°C to 7.64°C, and the temperature control precision requires more higher with the increase of signal light wavelength. The research results will lay a foundation for the design of high-throughput wide-spectrum tunable entangled photon sources.
Cryogenic radiometer is considered as the international benchmark for optical power measurement, which requires the core light radiation receiving device (cavity) has high absorption coefficient over 0.9999 at presented. In this paper, we have developed a new cavity are made of oxygen-free high-conductivity copper (OFHC) cylinder and coated with nickel-phosphorus (NiP) black paint. The cavity absorptance has been experimentally evaluated at different black paints and different structures. The result shows that the inclined bottom cylindrical cavity blackened with nickel-phosphorus black paint achieves an absorptance up to 0.9999964±0.000005; The most significant improvements in uncertainty arise from the enhanced characteristics of the cryogenic radiometer including its higher cavity absorptance and reduced non-equivalence effects.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.