Cunzhu Tong

Bio: Cunzhu Tong is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Laser & Quantum dot. The author has an hindex of 19, co-authored 157 publications receiving 1125 citations. Previous affiliations of Cunzhu Tong include University of Toronto & Nanyang Technological University.

Rate Equations for 1.3- $\mu$ m Dots-Under-a-Well and Dots-in-a-Well Self-Assembled InAs–GaAs Quantum-Dot Lasers

Abstract: A rate-equation model, in which three discrete quantum-dot (QD) energy levels are assumed and all possible relaxation paths and carrier transport in the GaAs barrier are considered, is presented to analyze the steady-state performance of 1.3 mum undoped and doped dots-under-a-well (DUW) and dots-in-a-well (DWELL) InAs-GaAs QD lasers. DWELL QD lasers have higher saturation value of QD level occupation probabilities and characteristic temperature (T0) than that of DUW QD lasers due to the improvement of hole confinement. The p-doped QD laser shows lower threshold current density than n-doped QD laser at the same threshold condition, and the T0 of n-doped DWELL laser is higher than that of p-doped DWELL laser at room temperature. Optimized QD layer number of DUW and DWELL QD lasers with different QD density is discussed

Low transparency current density and high temperature operation from ten-layer p-doped 1.3 μm InAs/InGaAs/GaAs quantum dot lasers

Abstract: High temperature photoluminescence up to 100°C was demonstrated from the p-doped ten-layer InAs∕InGaAs quantum dot (QD) laser structure. 1.3μm InAs QD lasers were fabricated using pulsed anodic oxidation from this structure. High output power of 882mW and low transparency current density of 5.9A∕cm2∕QD layer were obtained. Ground state (GS) lasing could be maintained from a QD laser with short cavity length of 611μm, corresponding to the maximum modal gain of 23.1cm−1 from this laser system. GS continuous wave operation up to 100°C was also demonstrated from an InAs QD laser (50×2500μm2).

Giant Kerr nonlinearity induced by tunneling in triple quantum dot molecules

Abstract: A scheme for giant enhancement of the Kerr nonlinearity in linear triple quantum dot molecules is proposed. In such a system, the tunneling-induced transparency window obtained in double quantum dot molecules splits into two windows, due to the coupling with the third quantum dot. And most important, the Kerr nonlinearity can be enhanced by several orders of magnitude, compared with that generated in double quantum dot molecules. With proper detuning of the tunneling, giant Kerr nonlinearity accompanied by vanishing absorption can be realized, which opens the possibility to enhance self-phase modulation in tunneling controllable semiconductor nanostructures under conditions of low light levels. Quantitative analysis shows that the giant Kerr nonlinearity is attributed to the interacting double dark resonances induced by the tunneling between the triple quantum dots, therefore no extra laser fields are required.

Principles Of Fluorescence Spectroscopy

Abstract: Thank you very much for downloading principles of fluorescence spectroscopy. As you may know, people have look hundreds times for their favorite novels like this principles of fluorescence spectroscopy, but end up in malicious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they cope with some harmful bugs inside their desktop computer. principles of fluorescence spectroscopy is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library spans in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the principles of fluorescence spectroscopy is universally compatible with any devices to read.

Controlling the dynamics of spontaneous emission from quantum dots by photonic crystals

Abstract: Control of spontaneously emitted light lies at the heart of quantum optics. It is essential for diverse applications ranging from miniature lasers and light-emitting diodes, to single-photon sources for quantum information, and to solar energy harvesting. To explore such new quantum optics applications, a suitably tailored dielectric environment is required in which the vacuum fluctuations that control spontaneous emission can be manipulated. Photonic crystals provide such an environment: they strongly modify the vacuum fluctuations, causing the decay of emitted light to be accelerated or slowed down, to reveal unusual statistics, or to be completely inhibited in the ideal case of a photonic bandgap. Here we study spontaneous emission from semiconductor quantum dots embedded in inverse opal photonic crystals. We show that the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal. Modified emission is observed over large frequency bandwidths of 10%, orders of magnitude larger than reported for resonant optical microcavities. Both inhibited and enhanced decay rates are observed depending on the optical emission frequency, and they are controlled by the crystals’ lattice parameter. Our experimental results provide a basis for all-solid-state dynamic control of optical quantum systems.

Transition metal-doped zinc chalcogenides: Spectroscopy and laser demonstration of a new class of gain media

Abstract: The absorption and emission properties of transition metal (TM)-doped zinc chalcogenides have been investigated to understand their potential application as room-temperature, mid-infrared tunable laser media. Crystals of ZnS, ZnSe, and ZnTe, individually doped with Cr/sup 2+/, Co/sup 2+/, Ni/sup 2+/, or Fe/sup 2+/ have been evaluated. The absorption and emission properties are presented and discussed in terms of the energy levels from which they arise. The absorption spectra of the crystals studied exhibit strong bands between 1.4 and 2.0 /spl mu/m which overlap with the output of strained-layer InGaAs diodes. The room-temperature emission spectra reveal wide-band emissions from 2-3 /spl mu/m for Cr and from 2.8-4.0 /spl mu/m for Co, Cr luminesces strongly at room temperature; Co exhibits significant losses from nonradiative decay at temperatures above 200 K, and Ni and Fe only luminesce at low temperatures, Cr/sup 2+/ is estimated to have the highest quantum yield at room temperature among the media investigated with values of /spl sim/75-100%. Laser demonstrations of Cr:ZnS and Cr:ZnSe have been performed in a laser-pumped laser cavity with a Co:MgF/sub 2/ pump laser. The output of both lasers were determined to peak at wavelengths near 2.35 /spl mu/m, and both lasers demonstrated a maximum slope efficiency of approximately 20%. Based on these initial results, the Cr/sup 2+/ ion is predicted to be a highly favorable laser ion for the mid-IR when doped into the zinc chalcogenides; Co/sup 2+/ may also serve usefully, but laser demonstrations yet remain to be performed.

Ultralow-threshold electrically pumped quantum-dot photonic-crystal nanocavity laser

Abstract: Researchers demonstrate continuous-wave lasing from a quantum dot photonic crystal nanocavity at temperatures of up to 150 K. The achieved lasing thresholds of 181 nA (at 50 K) and 287 nA (at 150 K) are record-lows for any type of electrically pumped laser.