Laser switch based on electric field modulated PT-symmetric structure

2020 ◽  
Vol 34 (14) ◽  
pp. 2050155
Author(s):  
Qing-Hua Cao ◽  
Yun-Tuan fang
Keyword(s):  
Electric Field ◽  
Optimization Design ◽  
Defect Mode ◽  
Structure Parameters ◽  
One Dimensional ◽  
Symmetric Structure ◽  
Maximum Value ◽  
Large Peak ◽  
Dynamical Control ◽  
Peak Value

In order to achieve a laser output at 1550 nm and a dynamical control, we perform an optimization design for one-dimensional PT-symmetric structure. The optimization is based on the structure parameters and the modulation of the external electric field. The optimization is performed by three steps: to achieve the defect mode, to achieve the amplification of the defect mode and to move the defect mode with a large peak value to the special wavelength 1550 nm. The maximum transmittance can reach 687.4. Through changing the electric field, the transmittance of the structure can be modulated to an arbitrary value from the cut-off state to its maximum value.

Electric-field-tunable defect mode in one-dimensional photonic crystal operating in the terahertz range

2013 ◽  
Vol 102 (24) ◽  
pp. 241106 ◽  
Author(s):  
V. Skoromets ◽  
H. Němec ◽  
C. Kadlec ◽  
D. Fattakhova-Rohlfing ◽  
P. Kužel
Keyword(s):  
Photonic Crystal ◽  
Electric Field ◽  
Defect Mode ◽  
Terahertz Range ◽  
One Dimensional ◽  
Dimensional Photonic Crystal

Structure Sensitivity Analysis and Dynamic Performance Optimization of Marine Gearbox

2017 ◽  
Author(s):  
Tengjiao Lin ◽  
Daokun Xie ◽  
Ziran Tan ◽  
Bo Liu
Keyword(s):  
Sensitivity Analysis ◽  
Performance Optimization ◽  
Optimization Design ◽  
Dynamic Performance ◽  
Structure Sensitivity ◽  
Superposition Method ◽  
Structure Parameters ◽  
Analysis Model ◽  
Vibration Acceleration ◽  
Response Optimization

The aim of this paper is to investigate the influence of structure parameters on the vibration characteristics and improve the dynamic performance of marine gearbox. A finite element model was established to solve the dynamic response by using modal superposition method. Based on the theory of multi-objective optimization design, the structure sensitivity analysis model of marine gearbox was established, which takes the structure parameters of the housing as design variables. The modal and response sensitivity was obtained by using the optimal gradient method. According to the results of sensitivity analysis, a modal and response optimization model of marine gearbox was established. The objective was to avoid natural frequencies from the excitation frequencies and minimize the root mean square of vibration acceleration of the evaluating points on the surface of housing. Then the modal optimization and response optimization of gearbox were carried out by using zero-order and first-order optimization method. The results indicate that the dynamic optimization of the gearbox can be achieved. After optimization, the amplitude of vibration acceleration of the evaluating points on the housing surface has been reduced and the resonance of marine gearbox can be avoided.

Numerical investigation on a melt-blowing die with internal stabilizers

2019 ◽  
pp. 152808371986693 ◽  
Author(s):  
Changchun Ji ◽  
Yudong Wang ◽  
Yafeng Sun
Keyword(s):  
Average Velocity ◽  
Fiber Diameter ◽  
Measurement Data ◽  
Melt Blowing ◽  
One Dimensional ◽  
Temperature Decay ◽  
Slot Die ◽  
The Common ◽  
The One ◽  
Peak Value

In order to decrease the fiber diameter and reduce the energy consumption in the melt-blowing process, a new slot die with internal stabilizers was designed. Using computational fluid dynamics technology, the new slot die was investigated. In the numerical simulation, the calculation data were validated with the laboratory measurement data. This work shows that the new slot die could increase the average velocity on the centerline of the air-flow field by 6.9%, compared with the common slot die. Simultaneously, the new slot die could decrease the back-flow velocity and the rate of temperature decay in the region close to the die head. The new slot die could reduce the peak value of the turbulent kinetic energy and make the fiber movements more gradual. With the one-dimensional drawing model, it proves that the new slot die has more edge on the decrease of fiber diameter than the common slot die.

Single Defect in Finite one Dimensional Photonic Crystals

2012 ◽  
Vol 614-615 ◽  
pp. 1629-1632
Author(s):  
Gang Xu ◽  
Yun Sun
Keyword(s):  
Photonic Crystals ◽  
Transmission Coefficient ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Defect Mode ◽  
Transmission Peak ◽  
Reflection And Transmission ◽  
One Dimensional ◽  
Single Defect ◽  
Reflection And Transmission Coefficient

Applying transfer matrix method, we get reflection and transmission coefficient of finite one dimensional photonic crystals. At the same time, we consider the position influence of single defect. We find the frequency of defect mode is same, but the height of transmission peak is not same when single defect is in different position of crystal. The transmission peak is maximum when the defect is in center of finite one dimensional photonic crystals.

PIEZOELECTRIC MATERIAL AND ONE-DIMENSIONAL PHONONIC CRYSTAL

2019 ◽  
Vol 26 (02) ◽  
pp. 1850144 ◽  
Author(s):  
ARAFA H. ALY ◽  
AHMED NAGATY ◽  
Z. KHALIFA
Keyword(s):  
Electric Field ◽  
Piezoelectric Material ◽  
Material Properties ◽  
Phononic Crystal ◽  
Defect Layer ◽  
Phononic Crystals ◽  
Localized Modes ◽  
One Dimensional ◽  
Energy Applications ◽  
Relative Change

We have theoretically obtained the transmittance properties of one-dimensional phononic crystals incorporating a piezoelectric material as a defect layer. We have used the transfer matrix method in our analysis with/without defect materials. By increasing the thickness of the defect layer, we obtained a sharp peak created within the bandgap, that indicates to the significance of defect layer thickness on the band structure. The localized modes and a particular intensity estimated within the bandgap depend on the piezoelectric material properties. By applying different quantities of an external electric field, the position of the peak shifts to different frequencies. The electric field induces a relative change in the piezoelectric thickness. Our structure may be very useful in some applications such as sensors, acoustic switches, and energy applications.

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