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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
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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
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InGaAs/InAlAs量子级联激光器研究 总被引:1,自引:0,他引:1
简要报道了自行研制的InGaAs/InAlAs量子级联激光器的制备及其主要特性,该器件具有增强型脊型波导结构,在80K时阈值电流为0.5A,相应的阈值电流密度为5KA/cm^2。 相似文献
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研究了Sn作Cu位元素替代的YBa2Cu3-xSnxOy超导体系(x=0-1.5)的正电子寿命谱,计算了局域电子密度和缺陷浓度的变化,发现了存在于高浓度替代区域(x=0.8-1.0)的正电子湮没特征,讨论了对超导电性的影响以及相应的物理机制。 相似文献
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