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为了测量K9玻璃的折射率,采用三次谐波法,通过调节位移平台使两束平行飞秒激光脉冲在时空上重合,进而产生强烈的三次谐波信号,并进行了理论分析和实验验证,对放入样品前后的实验数据进行处理,得到了样品K9柱面镜的折射率及其测量精度,还对两片折射率未知的衰减片进行了测量,得到了它们的折射率。结果表明,测得的样品折射率与实际折射率符合得很好,证实了该方法测量物体线性折射率的可行性;与传统测量方法相比,该方法具有操作简便、样品容易加工的优点,对样品折射率范围没有限制,具有很重要的实用价值。 相似文献
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空间计量是空间技术和计量学交叉产生的新生学科。地球上所有长期测量活动均需要周期性校准,然而地外空间的长期测量活动缺乏计量保障,这是空间计量学科面临的一个紧迫问题。在国际单位制的7个基本单位中与电磁量有关的是电流单位安培,与安培相关的单电子隧道效应很难实用化,目前地球上用于复现电流单位的约瑟夫森电压基准和量子化霍尔电阻基准也很难在地外空间维护。从实用性和工程可行性方面考虑,提出基于量子磁力仪的电流测量技术为未来空间电流计量的可选方案。简要分析了可用于空间电流计量的量子磁力仪,介绍了基于量子磁力仪的电流量值溯源和传递的实验方法,探讨了空间电流计量面临的一些物理原理、技术和工程问题。 相似文献
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交变磁场作为磁场一种特殊的存在形式,有着广泛的应用和学术价值,而现阶段没有行之有效的方法对交变磁场进行绝对测量。抽运-检测型原子磁力仪具有量程宽、灵敏度高、能准确反映磁场真实特性,在磁场测量及标定中具有非常重要的意义。通过对抽运-检测型原子磁力仪在交变磁场激励下作用机理研究,对实验装置进行改进,实现抽运-检测型原子磁力仪对交变磁场的绝对测量,在Z轴方向上实现了背景磁场40000 nT,频率为100 Hz、磁场强度幅值为1000 nT的交变磁场测量;在Y轴方向上实现了背景磁场1000 nT,频率为20 Hz、磁场强度幅值为500 nT的交变磁场测量。测量结果表明该实验装置适用于低频、弱磁场强度交变磁场的测量,该方法为交变磁场的测量和标定提供一种切实可行的技术手段。 相似文献
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Single-pulse and double-pulse optical emission spectroscopy (OES) analyses were carried out in air by using ultrashort laser pulses at atmospheric pressure. The aim of this work is to use spectroscopic methods to analyze the early phase of laser-induced plasma after the femtosecond laser pulse. The temporal behavior of emission spectra of air plasma has been characterized. In comparison with the single-pulse scheme, the plasma emission obtained in the double-pulse scheme presents a more intense continuum along with several additional ionic lines. As only one line is available in the single-pulse scheme, the plasma temperature measurements were performed using only the relative line-to-continuum intensity ratio method, whereas the relative line-to-line intensity ratio method and the relative line-to-continuum intensity ratio method were used simultaneously to estimate the electron temperature in the double-pulse scheme. The results reveal that the temperature values obtained by the two methods in the double-pulse scheme agree. Moreover, this shows that the relative line-to-continuum intensity ratio method is suitable for early phase of laser-induced plasma diagnostics. The electron number density was estimated using the Stark broadening method. In the early phase of laser-induced plasma, the temporal evolution of the electron number density exhibits a power law decrease with delay time. 相似文献
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在现代军事计量中,电磁计量直接影响国防建设质量和武器技战水平。现有电学计量体系中,基于约瑟夫森效应和量子化霍尔效应的量子电压和量子电阻的基准装置已经完成建设并已投入应用,然而基于量子效应的电流基准仍处于探索阶段。本论文基于高灵敏度原子磁力仪技术提出一种新型电流计量技术,可将电流间接溯源至约瑟夫森效应、量子化霍尔效应和拉莫尔进动效应三种量子自然基准。该技术有潜力用于建设电流计量基准装置和研制基于量子自然基准的新型电流比较仪。具体阐述了电流计量及量值传递方案的物理思想和实施过程,并通过相关实验验证了方案的可行性。 相似文献
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In this paper,an experimental study of collinear geometry double-pulse femtosecond LIBS was performed on a Ni sample in ambient air in an effort to clarify the contributing processes responsible for the signal enhancement observed in comparison with the single-pulse case.Doublepulse LIBS spectra show a very clear enhancement when an optimum inter-pulse delay was used.The influences of the inter-pulse delay between two pulses on the LIBS signal intensity,electron temperature and density were investigated.It is most remarkable that the evolutions of signal enhancement and electron temperature versus the inter-pulse delay showed the same behavior and revealed two main regimes of interaction.These results provide additional insight into the possible emission enhancement mechanisms in the double pulse configuration. 相似文献
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