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Zhi Ming Zhang - One of the best experts on this subject based on the ideXlab platform.
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Emission Probability and photon statistics of a coherently driven mazer
Journal of Physics B, 2002Co-Authors: Jin Xiong, Zhi Ming ZhangAbstract:The idea of a mazer is put forward with particular reference to the question of the driving-induced atomic coherence, which is established by a coherent driving field. The interaction of a quantum cavity field and an ultracold V-type three-level atom in which two levels are coupled by a coherent driving field, is derived. Its general quantum theory is established and the atomic Emission Probability and photon statistics are calculated and analysed. It is found that the mazer based on this driving-induced atomic coherence shows new features. There is a non-vanishing Probability for the atom emitting a photon in the cavity even when the resonance condition is not fulfilled (here the resonance condition means that the cavity length is an integer multiple of half the atomic de Broglie wavelength). Under the resonance condition, the atomic Emission Probability has two sets of resonance peaks. For a very strong coherent driving field, the Emission of the atom can be forbidden. As to the photon statistics, when the driving field is not very strong, the driving-induced atomic coherence reduces the photon number fluctuations of the cavity field. The photon statistics exhibits strong sub-Poissonian behaviour. In the region considered here, it can even be sub-Poissonian for any cavity length. However, when the driving field is too strong, the sub-Poissonian property may disappear.
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quantum theory of the two photon mazer Emission Probability
Physical Review A, 1999Co-Authors: Zhi Ming ZhangAbstract:We apply the concept of the mazer to the two-photon process and propose the idea of the two-photon mazer. We establish the general quantum theory of the two-photon mazer and calculate its Emission Probability in the special case of a mesa mode function. We study not only the case in which the cavity field is initially in a number state, but also the case in which the cavity field is initially in a coherent state. Under the condition of an initial coherent field, the Emission Probability shows the collapse-revival phenomena, which have different features in different regimes. In the thermal-atom regime, the collapse revivals are similar to that in the two-photon Jaynes-Cummings model. In the critical regime, the collapse revivals look like that in the one-photon Jaynes-Cummings model. In the ultracold-atom regime, the collapse revivals are different from those in the above two regimes. The reasons for these results have been analyzed.
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quantum theory of the two photon mazer general theory and Emission Probability
Chinese Physics Letters, 1999Co-Authors: Zhi Ming ZhangAbstract:The idea of the two-photon mazer (microwave amplification via z-motion-induced Emission of radiation) is put forward. The dressed states for the interaction of a cascade three-level atom with a quantum cavity field are derived. The general quantum theory of the two-photon mazer is established and its Emission Probability is studied. The effects of the atomic c.m. momentum and of the atom-field detuning are examined. It is found that the two-photon mazer shows new features that differ from both the one-photon mazer and the conventional two-photon micromaser.
Steven P Denbaars - One of the best experts on this subject based on the ideXlab platform.
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origin of defect insensitive Emission Probability in in containing al in ga n alloy semiconductors
Nature Materials, 2006Co-Authors: Shigefusa F Chichibu, Akira Uedono, T Onuma, Benjamin A Haskell, Arpan Chakraborty, T Koyama, P Fini, Stacia Keller, Steven P DenbaarsAbstract:Origin of defect-insensitive Emission Probability in In-containing (Al,In,Ga)N alloy semiconductors
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origin of defect insensitive Emission Probability in in containing al in ga n alloy semiconductors
Nature Materials, 2006Co-Authors: Shigefusa F Chichibu, Akira Uedono, T Onuma, Benjamin A Haskell, Arpan Chakraborty, T Koyama, P Fini, Stacia Keller, Steven P DenbaarsAbstract:Group-III-nitride semiconductors have shown enormous potential as light sources for full-colour displays, optical storage and solid-state lighting. Remarkably, InGaN blue- and green-light-emitting diodes (LEDs) emit brilliant light although the threading dislocation density generated due to lattice mismatch is six orders of magnitude higher than that in conventional LEDs. Here we explain why In-containing (Al,In,Ga)N bulk films exhibit a defect-insensitive Emission Probability. From the extremely short positron diffusion lengths (<4 nm) and short radiative lifetimes of excitonic Emissions, we conclude that localizing valence states associated with atomic condensates of In-N preferentially capture holes, which have a positive charge similar to positrons. The holes form localized excitons to emit the light, although some of the excitons recombine at non-radiative centres. The enterprising use of atomically inhomogeneous crystals is proposed for future innovation in light emitters even when using defective crystals.
Akira Uedono - One of the best experts on this subject based on the ideXlab platform.
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origin of defect insensitive Emission Probability in in containing al in ga n alloy semiconductors
Nature Materials, 2006Co-Authors: Shigefusa F Chichibu, Akira Uedono, T Onuma, Benjamin A Haskell, Arpan Chakraborty, T Koyama, P Fini, Stacia Keller, Steven P DenbaarsAbstract:Origin of defect-insensitive Emission Probability in In-containing (Al,In,Ga)N alloy semiconductors
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origin of defect insensitive Emission Probability in in containing al in ga n alloy semiconductors
Nature Materials, 2006Co-Authors: Shigefusa F Chichibu, Akira Uedono, T Onuma, Benjamin A Haskell, Arpan Chakraborty, T Koyama, P Fini, Stacia Keller, Steven P DenbaarsAbstract:Group-III-nitride semiconductors have shown enormous potential as light sources for full-colour displays, optical storage and solid-state lighting. Remarkably, InGaN blue- and green-light-emitting diodes (LEDs) emit brilliant light although the threading dislocation density generated due to lattice mismatch is six orders of magnitude higher than that in conventional LEDs. Here we explain why In-containing (Al,In,Ga)N bulk films exhibit a defect-insensitive Emission Probability. From the extremely short positron diffusion lengths (<4 nm) and short radiative lifetimes of excitonic Emissions, we conclude that localizing valence states associated with atomic condensates of In-N preferentially capture holes, which have a positive charge similar to positrons. The holes form localized excitons to emit the light, although some of the excitons recombine at non-radiative centres. The enterprising use of atomically inhomogeneous crystals is proposed for future innovation in light emitters even when using defective crystals.
Hiroshi Miyahara - One of the best experts on this subject based on the ideXlab platform.
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Emission Probability measurement of γ ray of 105rh
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2005Co-Authors: Kousuke Morita, Hiroshi Miyahara, Yoshimune Ogata, Keiji KatohAbstract:Abstract 105 Rh becomes a stable 105 Pd after β − -decay with a half-life of 35.36 h. The energies of especially strong γ-rays emitted from 105 Rh are 306.1 and 318.9 keV, and the Emission probabilities are evaluated to be 5.1±0.3% and 19.1±0.6% by de Frenne et al. To improve the certainty, the γ-ray Emission probabilities were determined from the disintegration rate and absolute γ-ray intensities measured using a 4πβ(ppc)-γ(HPGe) coincidence apparatus with two-dimensional data-acquisition system. The results for the 306.1 and 318.9 keV γ-rays were 4.76±0.05% and 16.99±0.17%, respectively.
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gamma ray Emission Probability measurement of 149eu
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2004Co-Authors: Hiroshi Miyahara, Keiji Katoh, Keiichi Ikeda, Kazuo Fujiki, I Nishinaka, K Tsukada, Y Nagame, M Asai, S Ichikawa, Hiromitsu HabaAbstract:Abstract The γ-ray Emission Probability of 149Eu was determined from the measurements of disintegration rates and γ-ray spectra of sources using a 4πβ-γ coincidence apparatus with a live-timed two-dimensional data-acquisition system. The determined Emission probabilities of the 277.1 and 327.5 keV γ-rays were 0.0413±0.0003 and 0.0475±0.0003, respectively. These results meant that the evaluated values were underestimated by about 15%. Finally, new values of the decay parameters were deduced from them.
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Emission Probability measurement of principal γ rays of 147eu
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2004Co-Authors: Hiroshi Miyahara, Keiji Katoh, Nada Marnada, Keiichi Ikeda, Kazuo Fujiki, I Nishinaka, K Tsukada, Y Nagame, M Asai, S IchikawaAbstract:Abstract The γ-ray Emission probabilities for the decay of 147 Eu by electron capture or β + -particle Emission were evaluated by der Mateosian and Peker (Nucl. Data Sheets 66 (1992) 705), but those had large uncertainties of about 4%. In this work precise γ-ray Emission probabilities of 147 Eu are based on source disintegration rates measured using a 4πβ–γ coincidence apparatus with a live-timed two-dimensional data-acquisition system. The Emission probabilities of the 121.2, 197.3, 601.5, 677.5 and 1077.0 keV γ-rays were determined to be 0.2061±0.0019, 0.2398±0.0022, 0.0589±0.0005, 0.1003±0.0010 and 0.0637±0.0006, respectively, from the absolute γ-ray Emission rates and the disintegration rates.
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precise measurement of the Emission Probability of the 543 kev γ ray of 199pt
Applied Radiation and Isotopes, 2004Co-Authors: Hiroshi Miyahara, Keiji Katoh, Yoshimune Ogata, Naoomi Ishikawa, Nada MarnadaAbstract:Abstract 199 Pt has been produced by neutron irradiation of enriched 198 Pt (95.71%) metal powder, and precise measurements have been made of the γ -ray Emission probabilities by means of 4 πβ − γ coincidence apparatus and a live-timed two-dimensional data-acquisition system. Daughter 199 Au decays with a half-life of 3.139 d, and therefore the measured disintegration rate had to be corrected. The absolute Emission Probability of the 543.0 keV γ ray was determined to be 0.1174±0.0007 from the γ -ray intensity and the corrected disintegration rate.
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Emission Probability measurement of 94 7 kev γ ray for 165dy
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2004Co-Authors: Hiroshi Miyahara, Keiji KatohAbstract:Abstract Emission Probability of γ-ray is one of the most important decay parameters of radionuclide and improvement of certainty is desired in many fields of research and application. 165 Dy decays to the ground or excited states of 165 Ho with a half-life of 2.334 h and emits 55 γ-rays. The Emission Probability of the most intense 94.7 keV γ-ray is evaluated to be 3.6±0.4% in Nuclear Data Sheets (50 (1987) 137). To improve the certainty, measurement was carried out using a 4πβ–γ coincidence apparatus with two-dimensional data-acquisition system. The measured Emission Probability of 94.7 keV γ-ray was 3.80±0.05% that was larger than the evaluated value by about 5% and the uncertainty was greatly improved.
Shigefusa F Chichibu - One of the best experts on this subject based on the ideXlab platform.
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origin of defect insensitive Emission Probability in in containing al in ga n alloy semiconductors
Nature Materials, 2006Co-Authors: Shigefusa F Chichibu, Akira Uedono, T Onuma, Benjamin A Haskell, Arpan Chakraborty, T Koyama, P Fini, Stacia Keller, Steven P DenbaarsAbstract:Origin of defect-insensitive Emission Probability in In-containing (Al,In,Ga)N alloy semiconductors
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origin of defect insensitive Emission Probability in in containing al in ga n alloy semiconductors
Nature Materials, 2006Co-Authors: Shigefusa F Chichibu, Akira Uedono, T Onuma, Benjamin A Haskell, Arpan Chakraborty, T Koyama, P Fini, Stacia Keller, Steven P DenbaarsAbstract:Group-III-nitride semiconductors have shown enormous potential as light sources for full-colour displays, optical storage and solid-state lighting. Remarkably, InGaN blue- and green-light-emitting diodes (LEDs) emit brilliant light although the threading dislocation density generated due to lattice mismatch is six orders of magnitude higher than that in conventional LEDs. Here we explain why In-containing (Al,In,Ga)N bulk films exhibit a defect-insensitive Emission Probability. From the extremely short positron diffusion lengths (<4 nm) and short radiative lifetimes of excitonic Emissions, we conclude that localizing valence states associated with atomic condensates of In-N preferentially capture holes, which have a positive charge similar to positrons. The holes form localized excitons to emit the light, although some of the excitons recombine at non-radiative centres. The enterprising use of atomically inhomogeneous crystals is proposed for future innovation in light emitters even when using defective crystals.