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	Mechanisms of energy transfer in Pr3+ and Cr3+ codoped SrAl12O19 phosphor (EI CONFERENCE) 会议论文 OAI收割 209th ECS Meeting, May 7, 2006 - May 12, 2006, Denver, CO, United states 作者: Zhang J.; Wang X.-J.; Zhang G.; Zhang G.; Zhang G. 收藏 \| 浏览/下载：18/0 \| 提交时间：2013/03/25 A two-step energy transfer was observed in Pr3+ and Cr 3+ codoped SrAl12O19 phosphor which results in a two-photon luminescence for one UV/vacuum-UV photon absorbed. For one Pr 3+ ion excited to the lowest 4f5d states two Cr3+ ions may be excited and emit two red photons due to 2E- 4A2 transitions of the Cr3+ ions Cr 3+ ions can be excited into the 4T1(F) levels by cross relaxation of Pr3+ 1S0- 1I6 or by direct energy transfer from Pr3+ 3P0 1 states. The mechanisms of the two-step energy transfer process were studied based on spectra and lifetime measurements. copyright The Electrochemical Society.
	Excitonic properties of vertically aligned ZnO nanotubes under high-density excitation (EI CONFERENCE) 会议论文 OAI收割 Lu Y. M.; Liang H. W.; Shen D. Z.; Zhang Z. Z.; Zhang J. Y.; Zhao D. X.; Liu Y. C.; Fan X. W. 收藏 \| 浏览/下载：13/0 \| 提交时间：2013/03/25 In this paper highly oriented and vertically arranged ZnO nanotubes are prepared on Al2O3 (0 0 0 1) substrate without employing any metal catalysts by plasma-assisted molecular beam epitaxy. The photoluminescence (PL) spectra at room temperature are studied under high excitation densities. Under lower excitation density (60 kW/cm2) PL spectrum shows that one strong free exciton emission (FE) locates at 3.306 eV. As the excitation density increases up to 200 kW/cm2 a new emission peak (Pn) located at low-energy side of FE is attributed to the spontaneous emission due to an exciton-exciton (Ex-E x) scattering process from two ground state excitons where one exciton is recombined by emitting a photon and the other is scattered into the excited states of n=2 3 4.... Under excitation density of 300 kW/cm 2 the stimulated emission originating from Ex-E x scattering is obtained. When the excitation density is above 580 kW/cm2 the emission from electron-hole plasma is observed in low-energy side of the P band and indicates a typical superradiation recombination processes with increasing excitation density. 2006 Elsevier B.V. All rights reserved.
	Energy upconversion in erbium doped oxyfluoride tellurite glass (EI CONFERENCE) 会议论文 OAI收割 ICO20: Materials and Nanostructures, August 21, 2005 - August 26, 2005, Changchun, China 作者: Chen B.; Xie Y.; Wang X.; Wang X.; Wang X. 收藏 \| 浏览/下载：16/0 \| 提交时间：2013/03/25 In this article we have investigated energy upconversion process in erbium doped oxyfuoride tellurite glasses exciated with 980 nm diode laser. The glasses used in measurements are with a mol% composition of 70TeO2-9PbF2-190AlF3-10BaF2-1Er2O3. The s intensity parameters the radiative rates the branching ratios and the fluorescence lifetimes were calculated based upon the Judd-Ofelt theory and the experimental absorption spectrum. Under 980 nm excitation efficient 530 544 and 665 nm upconversion emission are due to two-photon absorption processes.
	Anti-stokes fluorescent cooling by energy transfer (EI CONFERENCE) 会议论文 OAI收割作者: Zhang J.; Wang Y.; Wang Y.; Wang Y.; Wang Y. 收藏 \| 浏览/下载：16/0 \| 提交时间：2013/03/25 A new model on the mechanism of anti-Stokes fluorescent cooling is proposed based on which incident laser induces a phonon-assisted energy transfer from one luminescent center to another in an optical medium and causes medium cooling when the energy transfer is an anti-Stokes process and absorbs phonons. Here we develop the model in two cases: two-phonon-assisted energy transfer for a small energy mismatch and one-phonon-assisted energy transfer for a large energy mismatch. The dependence of relative cooling efficiency on photon energy and temperature is also discussed in evaluating the new mechanism. 2006 Elsevier B.V. All rights reserved.
	Energy transfer in Pr3+- and Cr3+-codoped SrAl 12O19 system (EI CONFERENCE) 会议论文 OAI收割作者: Luo Y.; Zhang X.; Zhang X.; Zhang X.; Zhang J. 收藏 \| 浏览/下载：17/0 \| 提交时间：2013/03/25 The energy transfer processes in Pr3+- and Cr 3+-codoped SrAl12O19 system are studied experimentally. The transfer can convert the 1S0 ultraviolet fluorescence of Pr3+ into the red emission of Cr 3+. The 3P0 state which may be populated by 1S0&rarr1I6 emission can also act as a donor state in the transfer to Cr3+. Cross-relaxation process is reported firstly in energy transfer between the pair of Pr 3+-Cr3+ in SrAl12O19 system. Two-step energy transfer is discussed which involves two visible photons for each vacuum ultraviolet photon absorbed. 2006 Elsevier B.V. All rights reserved.
	氦原子瞬态吸收光谱的阿秒啁啾效应研究学位论文 OAI收割作者: 赵海文 \| 收藏 \| 浏览/下载：56/0 \| 提交时间：2018/12/26 阿秒脉冲 Attosecond pulse 泵浦-探测 Pump-probe 瞬态吸收谱 Transient absorption 啁啾效应 Chirp effect 双光子过程 Two-photon process