全文获取类型
收费全文 | 19篇 |
免费 | 29篇 |
国内免费 | 37篇 |
专业分类
化学 | 1篇 |
晶体学 | 1篇 |
数学 | 1篇 |
物理学 | 37篇 |
无线电 | 45篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 11篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
排序方式: 共有85条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
正Distributed feedback(DFB) quantum cascade lasers(QCLs) in continuous-wave(CW) mode emitting atλ≈7.6μm are presented.Holographic lithography was used to fabricate the first-order distributed feedback grating. For a high-reflectivity-coated QCL with 14.5-μm-wide and 3-mm-long cavity,CW output powers of 300 mW at 85 K and still 10 mW at 270 K are obtained.Single-mode emission with a side-mode suppression ratio(SMSR) of about 30 dB and a wide tuning range of ~300 nm in the temperature range from 85 to 280 K is observed. 相似文献
5.
The fabrication and characterization of distributed feedback(DFB) quantum cascade lasers emitting atλ≈8.5μm are reported.The first-order DFB grating structure was defined using the holographic lithography technique.Reliable dynamic single-mode emission with a side-mode suppression ratio of 20 dB and a tuning coefficient of-0.277 cm-1/K from 93 to 210 K is obtained in continuous wave mode by using high-reflectivity coating on the rear facet.The output power is over 100 mW at a temperature of 80 K. 相似文献
6.
We report low-threshold high-temperature operation of 7.4#m strain-compensated InGaAs/lnAIAs quantum cascade lasers (QCLs). For an uncoated 22-μm-wide and 2-mm-long laser, the low-threshold current densities, i.e. 0.33kA/cm^2 at 81 K in pulsed mode and 0.64kA/cm^2 at 84K in cw mode, are realized. High-temperature operation of uncoated devices, with a high value of 223K, is achieved in cw mode. 相似文献
7.
采用自组装方法生长了一种新型的InGaAs量子点/InAlAs浸润层结构.通过选取合适的In组分 ,使InAlAs浸润层的能级与GaAs势垒相当,从而使浸润层的量子阱特征消失.通过低温光致 发光(PL)谱的测试分析得到InGaAs量子点/InAlAs浸润层在样品中的确切位置.变温PL谱的 研究显示,具有这种结构的量子点发光峰的半高全宽随温度上升出现展宽,这明显区别于普 通InGaAs量子点半高全宽变窄的行为.这是因为采用了InAlAs浸润层后,不仅增强了对InGaA s量子点的限制作用,同时切断了载流子的
关键词:
InGaAs量子点
InAlAs浸润层
PL谱 相似文献
8.
9.
A quantum cascade laser with a porous waveguide structure emitting at 4.5μm is reported.A branchlike porous structure filled with metal material was fabricated on both sides of the laser ridge by an electrochemical etching process.In contrast to the common ridge waveguide laser,devices with a porous structure give rather better beam quality.Utilizing this porous structure as a high-order mode absorber,the device exhibited fundamental transverse mode emission with a nearly diffraction limited far-field beam divergence angle of 4.9°. 相似文献
10.
Fourier transform infrared (FTIR) spectroscopy has moreadvantages over many other techniques for high resolu-tion studies in the mid-infrared and far-infrared spectralranges. In addition to the high frequency resolution, itexhibits a high signal-to-noise ratio (SNR), high through-put, and broad band range. There are two ways forthe spectrometer to implement the scan process, i.e.,the rapid-scan (continuous-scan) mode and the step-scan mode. Although many relatively simple rapid-scanFTIRs h… 相似文献