稠密V型介质中双色飞秒脉冲及频谱演化的RCEP调制

利用不含慢变振幅近似和旋波近似的全波Maxwell-Bloch方程组的数值解,研究单光子共振和失谐两种条件下,相对载波包络相位(RCEP)对在稠密V型三能级原子介质中传播的双色sech型飞秒超短脉冲及频谱演化的影响.结果表明,RCEP对双色脉冲的传播形式及频谱特性的调制在失谐情况比在单光子共振情况显著,在失谐条件下调节RCEP可获得比单光子共振条件下大得多的频谱展宽,出现了最高频率达到入射脉冲中心频率18倍的超连续谱.     

Single photon sources with single semiconductor quantum dots

In t.his contribution, we briefly recall the basic concepts of quantum optics and properties of semicon- ductor quantum clot. （QD） which a.re necessary to the nnderstanding of the physics of single-photon generation with single QDs. Firstly, we address the theory of quantmn emitter-cavity system, the fluorescence and optical properties of semiconductor QDs, and the photon statistics as well as opti- cal properties of the QDs. We then review the localizatioll of single semiconductor QDs in quantum confined optical microcavity systems to achieve their overall optical properties and perfornances in terms of strong coupling regime, elfieiency, directionality, and polarization control. Furthermore, we will discuss the recenl, progress on the fabrication of single photon sources, and various a.pproaehes for embedding single QDs into mieroca,vities or photonic crystal nanoeavities and show how to ex- tend the wavelength range. We focus in part;icular on new generations of electrically driven QD single photon source leading to high repetition rates, efficiencies at elevated temperature operation. Besides strong eoupling regime, and high collection new development;s of room temperature sin- gle photon emission in the strong coupling regime are reviewed. The generation of indistinguishable photons and remaining challenges for pract ical single-photon sources are also discussed.     

Single-photon modulation spectrum

We present a robust method of single-photon modulation by directly modulating the single photons and observe its frequency spectrum. Compared with conventional photon counting technique, the single-photon modulation spectrum shows that the method could not only realize high-frequency modulation but also obtain higher signal-to-noise ratio. Moreover, the theoretical calculations show good agreement with the experimental results.     

Phase-modulated Autler–Townes splitting in a giant-atom system within waveguide QED

The nonlocal emitter-waveguide coupling, which gives birth to the so called giant atom, represents a new paradigm in the field of quantum optics and waveguide QED. We investigate the single-photon scattering in a one-dimensional waveguide on a two-level or three-level giant atom. Thanks to the natural interference induced by the back and forth photon transmitted/reflected between the atom-waveguide coupling points, the photon transmission can be dynamically controlled by the periodic phase modulation via adjusting the size of the giant atom. For the two-level giant-atom setup, we demonstrate the energy shift which is dependent on the atomic size. For the driven three-level giant-atom setup, it is of great interest that, the Autler–Townes splitting is dramatically modulated by the giant atom, in which the width of the transmission valleys (reflection range) is tunable in terms of the atomic size. Our investigation will be beneficial to the photon or phonon control in quantum network based on mesoscopical or even macroscopical quantum nodes involving the giant atom.     

Blue‐green light generation using high brilliance edge emitting diode lasers

A review about second harmonic generation using edge emitting diode lasers and nonlinear crystals to obtain laser radiation in the blue‐green spectral range is presented. Therefore, pump laser radiation with high brightness and narrow bandwidth is necessary. Thus, this review gives an overview of the advances made with distributed feedback and Bragg reflector lasers, tapered lasers and amplifiers as well as external cavity diode lasers and master oscillator power amplifier schemes to achieve high brilliance emission. Since periodically poled materials have enabled high second harmonic conversion efficiencies with low and moderate pump powers, the review is focused on frequency doubling using those materials. The most commonly used materials, their properties and limitations are discussed briefly. Single pass and resonant SHG setups with waveguide and bulk nonlinear crystals are discussed and an emphasis on building compact and integrated devices is made.     

Rational Design of Mono- and Bi-Nuclear Cyclometalated Ir(III) Complexes Containing Di-Pyridylamine Motifs: Synthesis,Structure, and Luminescent Properties

Heteroleptic cyclometalated iridium (III) complexes (1–3) containing di-pyridylamine motifs were prepared in a stepwise fashion. The presence of the di-pyridylamine ligands tunes their electronic and optical properties, generating blue phosphorescent emitters at room temperature. Herein we describe the synthesis of the mononuclear iridium complexes [Ir(ppy)₂(DPA)][OTf] (1), (ppy = phenylpyridine; DPA = Dipyridylamine) and [Ir(ppy)₂(DPA-PhI)][OTf] (2), (DPA-PhI = Dipyridylamino-phenyliodide). Moreover, the dinuclear iridium complex [Ir(ppy)₂(L)Ir(ppy)₂][OTf]₂ (3) containing a rigid angular ligand “L = 3,5-bis[4-(2,2′-dipyridylamino)phenylacetylenyl]toluene” and displaying two di-pyridylamino groups was also prepared. For comparison purposes, the related dinuclear rhodium complex [Rh (ppy)₂(L)Rh(ppy)₂][OTf]₂ (4) was also synthesized. The x-ray molecular structure of complex 2 was reported and confirmed the formation of the target molecule. The rhodium complex 4 was found to be emissive only at low temperature; in contrast, all iridium complexes 1–3 were found to be phosphorescent in solution at 77 K and room temperature, displaying blue emissions in the range of 478–481 nm.     

Deep-Blue Triplet–Triplet Annihilation Organic Light-Emitting Diode (CIEy ≈ 0.05) Using Tetraphenylimidazole and Benzonitrile Functionalized Anthracene/Chrysene Emitters

Herein, new deep-blue triplet-triplet annihilation (TTA) molecules, namely 4-(10-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)anthracen-9-yl)benzonitrile (TPIAnCN) and 4-(12-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)chrysen-6-yl)benzonitrile (TPIChCN), are designed, synthesized, and investigated as emitters for organic light-emitting diodes (OLED). TPIAnCN and TPIChCN are composed of polyaromatic hydrocarbons of anthracene (An) and chrysene (Ch) as the cores functionalized with tetraphenylimidazole (TPI) and benzonitrile (CN) moieties, respectively. The experimental and theoretical results verify their excellent thermal properties, photophysical properties, as well as electrochemical properties. Particularly, their emissions are in the deep blue region, with TTA emissions being observed in their thin films. By utilization of these molecules as emitters, deep blue TTA OLEDs with CIE coordinates of (0.15, 0.05), high external quantum efficiency of 6.84%, and high exciton utilization efficiency (η_s) of 48% were fabricated. This result manifests the potential use of chrysene as an alternate building block to formulate new TTA molecules for accomplishing high-performance TTA OLEDs.     

氧化锌纳米线的紫外光耦合增强场电子发射特性

本文采用热化学气相沉积方法制备氧化锌纳米线阵列, 研究氧化锌纳米线阵列在紫外光辐照下的场电子发射特性. 实验结果表明, 在紫外光辐照下, 氧化锌纳米线场发射开启电压降低, 发射电流明显增大. 机理分析认为, 氧化锌纳米线紫外光增强的场发射源自场电子发射与半导体耦合作用, 紫外光激发价带电子跃迁到导带和缺陷能级使发射电子数量增加, 同时, 光生电子发射降低了发射材料表面的有效功函数, 从而显著增强场电子发射性能. 氧化锌纳米线具有紫外光耦合增强场电子发射特性, 在光传感、冷阴极平板显示和场发射电子源等方面具有潜在的应用价值.