Unidirectional single mode lasing realization and temperature induced mode switching in asymmetric GaN coupled cavities

Nanoscale ◽  
2022 ◽  
Author(s):  
Feifei Qin ◽  
Gangyi Zhu ◽  
Junbo Yang ◽  
Lai Wei ◽  
Qiannan Cui ◽  
...  

Effective lasing mode control and unidirectional coupling of semiconductor microlasers are vital to boost their applications in optical interconnects, on-chip communication and bio-sensors. In this paper, symmetric and asymmetric GaN...

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kun Ge ◽  
Dan Guo ◽  
Ben Niu ◽  
Zhiyang Xu ◽  
Jun Ruan ◽  
...  

Abstract Single mode lasers, particularly red-green-blue (RGB) colors, have attracted wide attention due to their potential applications in the photonic field. Here, we realize the RGB single mode lasing in a hybrid two-dimension and three-dimension (2D–3D) hybrid microcavity (μ-cavity) with a low threshold. The hybrid 2D–3D μ-cavity consists of a polymer fiber and a microsphere. Typical RGB polymer film consisting gain materials are cladded on a fiber. To achieve single mode lasing, the polymer fiber therein serves as an excellent gain cavity to provide multiple lasing modes while the microsphere acts as a loss channel to suppress most of the lasing modes. Mode switching can be realized by adjusting the pump position. It can be attributed to the change of coupled efficiency between gain μ-cavity and loss μ-cavity. Our work will provide a platform for the rational design of nanophotonic devices and on-chip communication.


2021 ◽  
Vol 54 (3-4) ◽  
pp. 360-373
Author(s):  
Hong Wang ◽  
Mingqin Zhang ◽  
Ruijun Zhang ◽  
Lixin Liu

In order to effectively suppress horizontal vibration of the ultra-high-speed elevator car system. Firstly, considering the nonlinearity of guide shoe, parameter uncertainties, and uncertain external disturbances of the elevator car system, a more practical active control model for horizontal vibration of the 4-DOF ultra-high-speed elevator car system is constructed and the rationality of the established model is verified by real elevator experiment. Secondly, a predictive sliding mode controller based on adaptive fuzzy (PSMC-AF) is proposed to reduce the horizontal vibration of the car system, the predictive sliding mode control law is achieved by optimizing the predictive sliding mode performance index. Simultaneously, in order to decrease the influence of uncertainty of the car system, a fuzzy logic system (FLS) is designed to approximate the compound uncertain disturbance term (CUDT) on-line. Furthermore, the continuous smooth hyperbolic tangent function (HTF) is introduced into the sliding mode switching term to compensate the fuzzy approximation error. The adaptive laws are designed to estimate the error gain and slope parameter, so as to increase the robustness of the system. Finally, numerical simulations are conducted on some representative guide rail excitations and the results are compared to the existing solution and passive system. The analysis has confirmed the effectiveness and robustness of the proposed control method.


Author(s):  
Yong-Zhen Huang ◽  
Jian-Dong Lin ◽  
Xiao-Meng Lv ◽  
Qi-Feng Yao ◽  
Jin-Long Xiao ◽  
...  

2018 ◽  
pp. 5-1-5-20
Author(s):  
Ian O′Connor ◽  
Frédéric Gaffiot

2009 ◽  
Vol 4 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Jacob S. Levy ◽  
Alexander Gondarenko ◽  
Mark A. Foster ◽  
Amy C. Turner-Foster ◽  
Alexander L. Gaeta ◽  
...  

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