We designed and fabricated a six-channel complex-coupled distributed feedback （DFB） quantum cascade laser arrays based on a sampled Bragg grating. The six-channel DFB laser arrays exhibit a linear tuning range of 74...We designed and fabricated a six-channel complex-coupled distributed feedback （DFB） quantum cascade laser arrays based on a sampled Bragg grating. The six-channel DFB laser arrays exhibit a linear tuning range of 74nm centered at a wavelength of 7.55μm at room temperature. Robust single-mode emission with a side mode suppression ratio about 20 dB was observed, even at full power. The used sampled grating and reflectivity coating on the back facet lead to the peak output power varying from 55 to 82 m W with a small difference in slope efficiency from 100 to 128mW/A.展开更多
A strain-compensated InP-based quantum cascade laser（QCL） structure emitting at 4.6 μm is demonstrated,based on a two-phonon resonant design and grown by solid-source molecular beam epitaxy（MBE）.By optimizing the...A strain-compensated InP-based quantum cascade laser（QCL） structure emitting at 4.6 μm is demonstrated,based on a two-phonon resonant design and grown by solid-source molecular beam epitaxy（MBE）.By optimizing the growth parameters,a very high quality heterostructure with the lowest threshold current densities ever reported for QCLs was fabricated.Threshold current densities as low as 0.47 kA/cm^2 in pulsed operation and 0.56 kA/cm^2 in continuous-wave（cw） operation at 293 K were achieved for this state-of-the-art QCL.A minimum power consumption of 3.65 W was measured for the QCL,uncooled,with a high-reflectivity（HR） coating on its rear facet.展开更多
目的:探究团体心理辅导对大学生心理健康水平及人际关系的影响以及相关性。方法:采用量表测试、开放式问卷与诊断性面谈相结合的方法,选取46名大学生,开展为期8周的团体心理辅导活动。以症状自评量表(SCL-90)、人际交往能力量表为评估工...目的:探究团体心理辅导对大学生心理健康水平及人际关系的影响以及相关性。方法:采用量表测试、开放式问卷与诊断性面谈相结合的方法,选取46名大学生,开展为期8周的团体心理辅导活动。以症状自评量表(SCL-90)、人际交往能力量表为评估工具,在辅导前、后分别对被试进行测查。结果:经过团体心理辅导,成员在冲突控制能力上差异显著(13.89 ±3.06/15.48 ±3.91, P 【0.05),在SCL-90症状自评量表上的得分存在显著性差异(t = 2.088, P 【0.05),团体辅导前的得分显著高于团体辅导后的得分,成员报告对活动效果感到满意。结论:团体心理辅导有益于解决大学生人际交往方面的心理问题,能够提高大学生人际交往水平,增进其心理健康且心理健康水平越高人际交往能力越强,呈正相关。展开更多
An external cavity quantum cascade laser （QCL） array with a wide tuning range and high output power is pre- sented. The coherent QCL array combined with a diffraction grating and gold mirror is tuned in the Littrow ...An external cavity quantum cascade laser （QCL） array with a wide tuning range and high output power is pre- sented. The coherent QCL array combined with a diffraction grating and gold mirror is tuned in the Littrow configuration. Taking advantage of the single-lobed fundamental supermode far-field pattern, the tuning capa- bility of 30.6cm-1 is achieved with a fixed injected current of 3.5 A at room temperature. Single-mode emission can be observed in the entire process. The maximum single-mode output power of the external cavity setup is as high as 25mW and is essential in real applications.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB632801, 2013CB632803 and 2011YQ13001802-04, and the National Natural Science Foundation of China under Grant Nos 61306058, 61274094 and 10990103.
文摘We designed and fabricated a six-channel complex-coupled distributed feedback （DFB） quantum cascade laser arrays based on a sampled Bragg grating. The six-channel DFB laser arrays exhibit a linear tuning range of 74nm centered at a wavelength of 7.55μm at room temperature. Robust single-mode emission with a side mode suppression ratio about 20 dB was observed, even at full power. The used sampled grating and reflectivity coating on the back facet lead to the peak output power varying from 55 to 82 m W with a small difference in slope efficiency from 100 to 128mW/A.
基金supported by the National Basic Research Program of China(Grant Nos.2013CB632801 and 2013CB632803)the National Natural Science Foundation of China(Grant Nos.61306058,61274094,and 61435014)the Beijing Natural Science Foundation(Grant No.4144086)
文摘A strain-compensated InP-based quantum cascade laser（QCL） structure emitting at 4.6 μm is demonstrated,based on a two-phonon resonant design and grown by solid-source molecular beam epitaxy（MBE）.By optimizing the growth parameters,a very high quality heterostructure with the lowest threshold current densities ever reported for QCLs was fabricated.Threshold current densities as low as 0.47 kA/cm^2 in pulsed operation and 0.56 kA/cm^2 in continuous-wave（cw） operation at 293 K were achieved for this state-of-the-art QCL.A minimum power consumption of 3.65 W was measured for the QCL,uncooled,with a high-reflectivity（HR） coating on its rear facet.
文摘目的:探究团体心理辅导对大学生心理健康水平及人际关系的影响以及相关性。方法:采用量表测试、开放式问卷与诊断性面谈相结合的方法,选取46名大学生,开展为期8周的团体心理辅导活动。以症状自评量表(SCL-90)、人际交往能力量表为评估工具,在辅导前、后分别对被试进行测查。结果:经过团体心理辅导,成员在冲突控制能力上差异显著(13.89 ±3.06/15.48 ±3.91, P 【0.05),在SCL-90症状自评量表上的得分存在显著性差异(t = 2.088, P 【0.05),团体辅导前的得分显著高于团体辅导后的得分,成员报告对活动效果感到满意。结论:团体心理辅导有益于解决大学生人际交往方面的心理问题,能够提高大学生人际交往水平,增进其心理健康且心理健康水平越高人际交往能力越强,呈正相关。
基金Supported by the National Basic Research Program of China under Grant No 2013CB632801the National Key Research and Development Program of China under Grant No 2016YFB0402303+2 种基金the National Natural Science Foundation of China under Grant Nos 61435014,61627822,61574136,61306058 and 61404131the Key Projects of Chinese Academy of Sciences under Grant No ZDRW-XH-2016-4the Beijing Natural Science Foundation under Grant No 4162060
文摘An external cavity quantum cascade laser （QCL） array with a wide tuning range and high output power is pre- sented. The coherent QCL array combined with a diffraction grating and gold mirror is tuned in the Littrow configuration. Taking advantage of the single-lobed fundamental supermode far-field pattern, the tuning capa- bility of 30.6cm-1 is achieved with a fixed injected current of 3.5 A at room temperature. Single-mode emission can be observed in the entire process. The maximum single-mode output power of the external cavity setup is as high as 25mW and is essential in real applications.
