Author Affiliations
Abstract
Key Laboratory of Computer Vision and System of Ministry of Education, Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology, Tianjin University of Technology, Tianjin 300384, China
A solid-state green-light-emitting upconversion coherent random laser was realized by pumping macroporous erbium-doped lithium niobate with a 980 nm laser. The lasing threshold was determined to be about 40 kW/cm2. Above the threshold, the emission intensity increased sharply with the increasing pump intensity. Moreover, a narrow multi-peaks structure was observed in the green-light-emission band, and the positions of lasing lines were various at different angles. The results were the direct evidences of coherent random lasing emission from macroporous erbium-doped lithium niobate. These phenomena were attributed to the coexistence of upconversion emission and a multiple scattering feedback mechanism.
140.7300 Visible lasers 290.4210 Multiple scattering 160.5690 Rare-earth-doped materials Chinese Optics Letters
2018, 16(1): 011403
1 天津理工大学电气电子工程学院,天津 300384
2 天津理工大学计算机视觉与系统省部共建教育部重点实验室,天津 300384
3 天津市智能计算及软件新技术重点实验室,天津 300384
4 天津理工大学计算机科学与工程学院,天津 300384
结构光透过生物组织、沙尘等强散射介质时历经多重散射,会改变原有相位信息和传播方向,破坏相干性,最后形成散斑。本文主要针对结构光重构特征和适用性进行分析,以条形结构光作为入射光,透过散射介质后,分别运用直接求逆法、相位共轭法和TVAL3法对其进行重构,并分析不同测量噪声水平下,三种方法对条形结构光的重构效果。仿真结果表明: 测量噪声水平为0时,直接求逆法能得到较完美的重构效果; 存在测量噪声且测量噪声水平小于0.025 I时,TVAL3法能较好实现重构,而相位共轭法重构效果一直较差。同时,也运用三种方法实现了单点、三点的点光源重构。
散射介质 结构光重构 测量噪声 scattering medium structured light reconstruction TVAL3 TVAL3 measurement noise
Author Affiliations
Abstract
In this Letter, we investigate the packet error rate (PER) performance of digital pulse interval modulation (DPIM) for free-space optical (FSO) links under the combined effect of turbulence and pointing errors. The theoretical model is developed by considering the effect of some important parameters, including turbulence condition, beamwidth, receiver aperture size, jitter variance, data rate, transmitted optical power, etc. A closed-form average PER expression for DPIM is derived for this fading channel. The results of numerical simulation are further provided to verify the validation of our model. This work can be helpful for selecting DPIM in the FSO system design.
010.1300 Atmospheric propagation 010.1330 Atmospheric turbulence 060.2605 Free-space optical communication 060.4080 Modulation Chinese Optics Letters
2014, 12(s1): S10101
Author Affiliations
Abstract
A closed-form bit-error rate (BER) expression is derived for free-space optical (FSO) communication systems with circle polarization shift keying and spatial diversity receivers in the gamma-gamma (GG) distribution fading channel. This model can predict the performance without the need of lengthy simulation runs. The performance can be analyzed by some system parameters such as atmospheric conditions, link length, communication wavelength, receiver aperture size, and number of spatial diversity receivers. Numerical results demonstrate the influence of the above parameters on the FSO systems and show quantitatively the differences in behavior among various different parameters.
010.1300 Atmospheric propagation 010.1330 Atmospheric turbulence 060.2605 Free-space optical communication 060.4080 Modulation Chinese Optics Letters
2013, 11(s2): S20101
