Broad bandwidth interference filter-stabilized external cavity diode laser with narrow linewidth below 100kHz

Interference filter-stabilized external cavity diode lasers(ECDLs) have properties of simple configurations, high stabilities, and narrow linewidths. However, the interference filter used in common ECDL designs requires an ultra-narrow bandwidth(about 0.3 nm) to achieve mode selection, that is considerably expensive and not yet available for a wide range of wavelengths. In this paper, a robust ECDL using an available broad bandwidth(about 4 nm) interference filter as the wavelength discriminator is constructed and tested. The ECDL demonstrated a narrow Lorentzian fitted linewidth of 95 kHz and a spectral purity of 2.9 MHz. The long-term frequency stability of the ECDL reaches 5.59×10~(-12).     

Improved thermal property of strained InGaAlAs/AlGaAs quantum wells for 808-nm vertical cavity surface emitting lasers

The 808-nm vertical cavity surface emitting laser (VCSEL) with strained In_0.13Ga_0.75Al_0.12As/Al_0.3Ga_0.7As quantum wells is designed and fabricated. Compared with the VCSELs with Al_0.05Ga_0.95As/Al_0.3Ga_0.7As quantum wells, the VCSEL with strained In_0.13Ga_0.75Al_0.12As/Al_0.3Ga_0.7As quantum wells is demonstrated to possess higher power conversion efficiency (PCE) and better temperature stability. The maximum PCE of 43.8% for 10-μm VCSEL is achieved at an ambient temperature of 30 ℃. The size-dependent thermal characteristics are also analyzed by characterizing the spectral power and output power. It demonstrates that small oxide-aperture VCSELs are advantageous for temperature-stable performance.     

期权定价Black-scholes公式的一个新推导

文章提出Black scholes公式的一个新推导.在风险中性定价的框架下,通过对正态分布的性质及其矩母函数的熟练运用,可以快速容易地导出Black-scholes公式.并且在此推导过程中,公式中的概率值Φ(d1),Φ(d2)的含义得以明确体现.     

高功率转换效率905 nm垂直腔面发射激光器的设计与制备

通过对影响垂直腔面发射激光器(vertical cavity surface emitting laser, VCSEL)的功率转换效率的因素进行理论分析,得出斜率效率是影响功率转换效率的主要因素的结论.为获得高功率转换效率,通过对有源区量子阱、P型和N型分布布拉格反射镜(DBR)等进行优化,设计出了905 nm VCSEL的外延结构并进行了高质量外延生长.成功制备出了不同氧化孔径的905 nm VCSEL器件,获得的最大斜率效率为1.12 W/A,最大转换效率为44.8%.此外,探究了氧化孔径对VCSEL的远场和光谱特性的影响.这种具有高功率转换效率的905 nm VCSEL器件为激光雷达的小型化、低成本化提供了良好的基础数据.     

高功率密度多结级联905 nm垂直腔面发射激光器

本文针对激光雷达等三维传感应用,设计并制备了905 nm波长的高功率密度5结级联垂直腔面发射激光器(vertical cavity surface emitting laser, VCSEL).制备的5结级联VCSEL单管(氧化孔径8μm)的功率转换效率高达55.2%;其最大斜率效率为5.4 W/A,约为相同孔径单结VCSEL的5倍.窄脉冲条件下(脉冲宽度为5.4 ns,占空比0.019%), 5结级联19单元VCSEL阵列(单元孔径20μm)的峰值输出功率达到58.3 W,对应的峰值功率密度高达1.62 kW/mm².对不同孔径器件(8—20μm)的光电特性进行了测试和分析.结果显示,这些器件的最大斜率效率均大于5.4 W/A,最大功率转换效率均大于54%.这些高性能VCSEL器件可作为激光雷达等三维传感应用的理想光源.