scholarly journals Tailoring the properties of quantum dot-micropillars by ultrafast optical injection of free charge carriers

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Emanuel Peinke ◽  
Tobias Sattler ◽  
Guilherme M. Torelly ◽  
Patricia L. Souza ◽  
Sylvain Perret ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Time Scale ◽  
Dynamic Properties ◽  
Rotational Symmetry ◽  
Optical Injection ◽  
Large Set ◽  
Free Carriers ◽  
Ultrafast Optical ◽  
Resonance Frequencies ◽  
Cavity System

AbstractWe review recent studies of cavity switching induced by the optical injection of free carriers in micropillar cavities containing quantum dots. Using the quantum dots as a broadband internal light source and a streak camera as detector, we track the resonance frequencies for a large set of modes with picosecond time resolution. We report a record-fast switch-on time constant (1.5 ps) and observe major transient modifications of the modal structure of the micropillar on the 10 ps time scale: mode crossings are induced by a focused symmetric injection of free carriers, while a lifting of several mode degeneracies is observed when off-axis injection breaks the rotational symmetry of the micropillar. We show theoretically and experimentally that cavity switching can be used to tailor the dynamic properties of the coupled QD–cavity system. We report the generation of ultrashort spontaneous emission pulses (as short as 6 ps duration) by a collection of frequency-selected QDs in a switched pillar microcavity. These pulses display a very small coherence length, attractive for ultrafast speckle-free imaging. Moreover, the control of QD-mode coupling on the 10 ps time scale establishes cavity switching as an appealing resource for quantum photonics.

scholarly journals Designing of Drive Systems in the Aspect of the Desired Spectrum of Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2562
Author(s):  
Tomasz Dzitkowski ◽  
Andrzej Dymarek ◽  
Jerzy Margielewicz ◽  
Damian Gąska ◽  
Lukasz Orzech ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Dynamic Parameters ◽  
Synthesis Algorithm ◽  
Moments Of Inertia ◽  
Driving System ◽  
Six Degrees Of Freedom ◽  
Resonance Frequencies ◽  
Drive Systems ◽  
Power Component

A method for selecting dynamic parameters and structures of drive systems using the synthesis algorithm is presented. The dynamic parameters of the system with six degrees of freedom, consisting of a power component (motor) and a two-speed gearbox, were determined, based on a formalized methodology. The required gearbox is to work in specific resonance zones, i.e., meet the required dynamic properties such as the required resonance frequencies. In the result of the tests, a series of parameters of the drive system, defining the required dynamic properties such as the resonance and anti-resonance frequencies were recorded. Mass moments of inertia of the wheels and elastic components, contained in the required structure of the driving system, were determined for the selected parameters obtained during the synthesis.

scholarly journals Ultrafast optical properties of type-II CdZnS/ZnSe core-shell quantum dots

2018 ◽  
Vol 26 (14) ◽  
pp. 18480 ◽  
Author(s):  
Lingling Ran ◽  
Haiyang Li ◽  
Wenzhi Wu ◽  
Yachen Gao ◽  
Zhijun Chai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Core Shell ◽  
Type Ii ◽  
Ultrafast Optical

scholarly journals Effect of Grain Refinement on the Dynamic, Mechanical Properties, and Corrosion Behaviour of Al-Mg Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1825
Author(s):  
Haitham M. Ahmed ◽  
Hussin A. M. Ahmed ◽  
Mohammed Hefni ◽  
Essam B. Moustafa
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Corrosion Behaviour ◽  
Cast Alloy ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Xrd Analysis ◽  
Optical Microscope ◽  
Mg Alloy ◽  
Resonance Frequencies

In this investigation, aluminium Al-2.5% Mg cast alloy was modified by adding 0.5 Ti and 0.1 B wt % modifiers to investigate their impact on the dynamic behaviour, as well as the mechanical and microstructure properties. The dynamic properties were analysed experimentally using a free vibration impact test and predicted using finite element methods. This study used a high-resolution polarised optical microscope to analyse the microstructure of the studied alloys and X-ray Powder Diffraction (XRD) analysis to determine the developed phases. Microstructure and mechanical properties were mostly enhanced as a result of grain refining during solidification and through the metal segregation process. The microstructure analysis of the modified alloy showed a significant improvement in the grain refinement; hence, the grains were 10 times finer than the cast alloy. The modified Al-2.5% Mg/Ti-B alloy demonstrated reduced inter-granular corrosion (IGC) than the Al-2.5% Mg standard cast alloy. By incorporating Ti-B modifiers into the composition of the cast Al-Mg alloy, the ultimate tensile strength (UTS), strain (ε), and hardness values (HV) were increased by 30.5%, 100%, and 18.18%, respectively. The dynamic properties of the modified alloy showed an enhancement in the resonant (fn) and damping ratio (ζ) by 7% and 68%, respectively. The predicted resonance frequencies of the investigated alloys showed results close to the experimental dynamic tests.

Ultrafast Optical Physic Properties of CdSeS Quantum Dots

2013 ◽  
Vol 33 (10) ◽  
pp. 1032001
Author(s):  
安美英 An Meiying ◽  
张郑兵 Zhang Zhengbing ◽  
金钻明 Jin Zuanming ◽  
林贤 Lin Xian ◽  
马国宏 Ma Guohong
Keyword(s):  
Quantum Dots ◽  
Ultrafast Optical

Sub-Poissonian photon emission in coupled double quantum dots–cavity system

2015 ◽  
Vol 24 (11) ◽  
pp. 114202
Author(s):  
Han Ye ◽  
Yi-Wei Peng ◽  
Zhong-Yuan Yu ◽  
Wen Zhang ◽  
Yu-Min Liu
Keyword(s):  
Quantum Dots ◽  
Photon Emission ◽  
Double Quantum ◽  
Double Quantum Dots ◽  
Cavity System

scholarly journals Nonlinear Dynamics of Exclusive Excited-State Emission Quantum Dot Lasers Under Optical Injection

Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 58 ◽  
Author(s):  
Zai-Fu Jiang ◽  
Zheng-Mao Wu ◽  
Elumalai Jayaprasath ◽  
Wen-Yan Yang ◽  
Chun-Xia Hu ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Dynamic Properties ◽  
Optical Injection ◽  
Permutation Entropy ◽  
Frequency Detuning ◽  
Nonlinear Dynamical ◽  
Injection Coefficient ◽  
Nonlinear Dynamic Properties ◽  
Linewidth Enhancement

We numerically investigate the nonlinear dynamic properties of an exclusive excited-state (ES) emission quantum dot (QD) laser under optical injection. The results show that, under suitable injection parameters, the ES-QD laser can exhibit rich nonlinear dynamical behaviors, such as injection locking (IL), period one (P1), period two (P2), multi-period (MP), and chaotic pulsation (CP). Through mapping these dynamic states in the parameter space of the frequency detuning and the injection coefficient, it can be found that the IL occupies a wide region and the dynamic evolution routes appear in multiple forms. Via permutation entropy (PE) calculation to quantify the complexity of the CP state, the parameter range for acquiring the chaos with high complexity can be determined. Moreover, the influence of the linewidth enhancement factor (LEF) on the dynamical state of the ES-QD laser is analyzed. With the increase of the LEF value, the chaotic area shrinks (expands) in the negative (positive) frequency detuning region, and the IL region gradually shifts towards the negative frequency detuning.

Synthesis and Structural, Optical, and Dynamic Properties of Core/Shell/Shell CdSe/ZnSe/ZnS Quantum Dots

2012 ◽  
Vol 116 (47) ◽  
pp. 25065-25073 ◽  
Author(s):  
Bob C. Fitzmorris ◽  
Jason K. Cooper ◽  
Jordan Edberg ◽  
Sheraz Gul ◽  
Jinghua Guo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Dynamic Properties ◽  
Core Shell

Reducing inhomogeneity in the dynamic properties of quantum dots via self-aligned plasmonic cavities

2017 ◽  
Vol 29 (1) ◽  
pp. 015201
Author(s):  
Brandon Demory ◽  
Tyler A Hill ◽  
Chu-Hsiang Teng ◽  
Hui Deng ◽  
P C Ku
Keyword(s):  
Quantum Dots ◽  
Dynamic Properties

SYMMETRY BREAKING PHENOMENA IN MESOSCOPIC SYSTEMS: QUANTUM DOTS AND ROTATING NUCLEI

2009 ◽  
Vol 18 (04) ◽  
pp. 1014-1021
Author(s):  
R. G. NAZMITDINOV ◽  
A. PUENTE
Keyword(s):  
Quantum Dots ◽  
Symmetry Breaking ◽  
Rotational Symmetry ◽  
Random Phase ◽  
Mean Field ◽  
Rotating Frame ◽  
Octupole Deformation ◽  
The Mean ◽  
Symmetry Breaking Phenomena ◽  
Rotating Nuclei

A brief description of excited and ground states in two-dimensional quantum dots and rotating nuclei is presented within a mean field approach and a random-phase approximation (RPA). We discuss the procedure to restore the rotational symmetry broken at the mean field, which can be extended for other symmetry breaking cases. We propose to consider a disappearance of collective excitations in the rotating frame as a manifestation of symmetry breaking phenomena of the rotating mean field. In particular, we demonstrate that the disappearance of a collective octupole mode in the rotating frame in 162 Yb gives rise to the nonaxial octupole deformation.

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