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激光束照射液体产生的热累积效应会引起其折射率变化,从声光方程出发分别分析了液体瞬态折射率与稳态热致折射率产生的机理,研究了透镜焦距以及入射波长对去离子水折射率的影响.利用表面等离子体共振检测系统对温度改变的高度敏感性,建立了一种新型的液体棱镜检测系统,数值模拟了不同功率下去离子水的稳态共振曲线,当功率变化为0.7 W时,其折射率变化为1.4×10-3.采用功率可调的980nm的连续激光器对去离子水的热光效应进行了实验研究,得到了其稳态热致折射率随功率的变化关系,当功率变化0.7 W时,其折射率变化为3.35×10-3,最后剖析了实验与理论之间误差的可能来源. 相似文献
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Nano-carbon films with large density of caterpillar-like clavae are synthesized by microwave plasma-assisted chemical vapor deposition using a mixture of methane and hydrogen gases on Mo film substrates. The films are characterized by Raman spectra, optical microscopy and field emission scanning electron microscopy. Field electron emission measurements of nano-carbon films are also carried out to show the turn-on field as low as 1.5 V/μm and the high current density of 2.2mA/cm^2 at electric field of 5.TV/μm, the uniformly distributed emission site density from a broad well-proportioned emission area of about 4.0cm^2 is also obtained. The field- emission current density J versus macroscopic electric field E does not follow the original Fowler-Nordheim (F-N) relation since they are not well represented in the F-N plot by a straight line. A modified F-N relation is applied successfully to explain all the field-emission data observed for E 〈 6.0 V/μm. 相似文献
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<正>Graphene films are deposited on copper(Cu) and aluminum(Al) substrates,respectively,by using a microwave plasma chemical vapour deposition technique.Furthermore,these graphene films are characterized by a field emission type scanning electron microscope(FE-SEM),Raman spectra,and field emission(FE) I-V measurements.It is found that the surface morphologies of the films deposited on Cu and Al substrates are different:the field emission property of graphene film deposited on the Cu substrate is better than that on the Al substrate,and the lowest turn-on field of 2.4 V/μm is obtained for graphene film deposited on the Cu substrate.The macroscopic areas of the graphene samples are all above 400 mm~2. 相似文献
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