The quantum candela: a re-definition of the standard units for optical radiation

Cheung, Jessica Y.; Chunnilall, Christopher J.; Woolliams, Emma; Fox, Nigel; Mountford, John R.; Wang, J.; Thomas, Peter J.

doi:10.1080/09500340600769521

Cited by 72 publications

(37 citation statements)

References 38 publications

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“…He left behind a respectable body of research that led to the modern approach to assessment of retinal illuminance, the accepted unit used to specify the stimulus to vision [1][2][3]. We also call attention to the recent paper by Cheung et al, which addresses the standard units of optical radiation [4].…”

Section: It Is Time For a Reasoned Reassessment Ofmentioning

confidence: 99%

Integration of the Stiles–Crawford effect of the first kind

Enoch

Lakshminarayanan

2009

Journal of Modern Optics

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In 1932/1933, Walter Stanley Stiles and Brian Hewson Crawford, sought to measure the area of the entrance pupil of their subject's eyes. They assumed all portions of the entrance pupil of the eye contributed equally to visual excitation. Their pupillometer did not function as hypothesized. Using photopic stimuli, they found lightrays entering the pupil center had greater capability to stimulate vision than rays penetrating peripheral portions of the pupil. They deduced the reason for this failure, and discovered the Stiles-Crawford effect of the first kind (SCE-1), or 'the directional sensitivity of the retina'. This important finding resulted in numerous fine studies, but integration of excitation across the entrance pupil of the eye, per se, has been rarely considered. At a later date, Enoch, then Drum, addressed this problem. We address integration and specification of visual stimuli, consider confounds, such as the effects of aberration-induced blur, and the means of mitigating confounds encountered. We consider use of adaptive optics for these purposes.Keywords: visual stimulus; photometry; retinal illuminance; troland (and photopic and scotopic trolands); Stiles-Crawford effect of the first kind (SCE-1); integration of the SCE-1; methods of comparison of visual stimuli (bipartite fields, flicker photometry); aberrations of the eye (e.g. spherical aberration, chromatic aberration(s))

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Section: It Is Time For a Reasoned Reassessment Ofmentioning

confidence: 99%

Integration of the Stiles–Crawford effect of the first kind

Enoch

Lakshminarayanan

2009

Journal of Modern Optics

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“…One can envisage that SPSs possessing two level behavior could be implemented as a "single photon standard", able to link classical radiometric measurements to fundamental quantum optical entities. In particular, in the long term such a single photon standard could contribute to a redefinition of the standard units for optical radiation in terms of the "quantum candela" [219]. A solid understanding of the fabrication methods for an effective two level emitter is expected to progress the technology to the point where they can become practical quantum information and metrology devices.…”

Section: Ultra Bright Single Photon Sources In Cvd Diamond Crystalsmentioning

confidence: 99%

Novel Single Photon Emitters Based on Color Centers in Diamond

Aharonovich¹,

Castelletto²,

Prawer³

2011

AIP Conference Proceedings

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Exploitation of emerging quantum technologies requires efficient fabrication of key building blocks. Single photon sources are one of these fundamental constituents that are presently pushing the bounds of existing materials and fabrication techniques. Color centers in diamond are very attractive in this respect since they are the only photostable solid-state single photon emitters operating at room temperature known to date.The Nitrogen-Vacancy (NV) complex is one example of such an optical center and has been subject to intensive research due to the availability of optical readout of its individual electronic spin state. However, the NV center has fundamental limitations: strong phonon coupling of the excited state which results in a broad photoluminescence spectrum (~ 100 nm) of which the zero-phonon line makes up only 4%. Emission of single photons in the zero phonon line is then extremely weak, typically on the order of a few thousands of photons per second. Such count rates are insufficient for the realization of advanced quantum information processing protocols.To move beyond the limitations of the NV there is an emerging need to identify and fabricate novel diamond based single photon emitters with improved photo-physical characteristics. Development of such emitters is the main goal of this thesis.We first concentrate on the recent progress in materials science and fabrication techniques of high quality nanodiamond crystals. We demonstrate the ability to grow high quality, submicron sized diamond crystals with a control over their final size and density using a microwave assisted chemical vapor deposition.We then study two methodologies to engineer diamond based single photon emitters in the grown nanodiamonds. In the first, nickel is implanted into the substrate onto which the nanocrystals are subsequently grown. During the diamond growth, the substrate is slightly etched and the nickel atoms diffuse and incorporate into the growing crystals. In the second we employ direct ion implantation of nickel into already deposited individual diamond nanocrystals. Optical and correlation spectroscopy measurements reveal that these methodologies are effective to fabricate nickel related single photon emitters, with zero phonon lines centered in the near infra-red and a short excited state lifetime (~3 ns).ii Furthermore, the ability of diamond to host various luminescence centers prompted the discovery of a new class of ultra bright single photon emitters. These new emitters found in diamond crystals grown on sapphire substrate and assigned to chromium, which is present in the substrate and incorporated into the crystal during the growth. Nanodiamonds hosting these centers deliver outstanding performance such as narrow photoluminescence in the near infra-red and ultra bright single photon emission with count rate of ~ 3.2×10 6 counts/s -the brightest single photon source known to date.Importantly, some of the emitters exhibit a photon statistics without any photon bunching at saturation, indicating a two-...

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“…To improve the uncertainty of the primary two-photon beam method, more efficient sources of correlated photons are required and faster detection systems to link the photon counting directly to the analogue regime of optical power standards. In terms of conventional radiometry, a microwatt cryogenic radiometer is presently under development [18], with a next-step project of a photon flux cryogenic radiometer undergoing measurement of photon flux of 10 10 s −1 , taking advantage of developments in superconducting technology. On the side of sources, a possible generator of correlated photons comes from the development of χ (3) single-mode photonic fiber-based sources with pair rates up to 10 7 s −1 , with very low input pump power [16,17].…”

Section: Practical Heralded Single Photon Sources For Radiometrymentioning

confidence: 99%

“…In the area of metrology, more specifically radiometry, high-speed photon detection capability could allow the realization of a very bright single-photon source as a photon standard, that in the long term could bring a new radiometric standard yielding a "quantum candela" [18], i.e. a redefinition of the candela based on a countable photon source.…”

Section: Introductionmentioning

confidence: 99%

Heralded single photon sources: a route towards quantum communication technology and photon standards

Castelletto

Scholten

2008

Eur. Phys. J. Appl. Phys.

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Abstract. Single photon counting, based on single photon sources and detectors, is a key ingredient for certain applications aiming at new quantum information technologies. Quantum cryptography, quantum radiometry, distributed quantum computing, as well as adjacent technologies such as biomedical and astronomical imaging, and low power classical communication also rely on single-photon technology. This paper reviews the present status of single photon sources and related counting measurement techniques, based on correlated (or heralded) photons in parametric down-conversion, and their possible impact on the above mentioned technologies, as well as an assessment for photon standards in the future. PACS

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The quantum candela: a re-definition of the standard units for optical radiation

Cited by 72 publications

References 38 publications

Integration of the Stiles–Crawford effect of the first kind

Integration of the Stiles–Crawford effect of the first kind

Novel Single Photon Emitters Based on Color Centers in Diamond

Heralded single photon sources: a route towards quantum communication technology and photon standards

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