高精度光学频率合成技术研究

发布时间：2018-07-05 00:12

本文选题：光学频率合成 + 光学频率梳　；参考：《华东师范大学》2017年博士论文

【摘要】：光原子钟的频率不稳定度和不确定度都已达到1 0-18量级,它们在在基本物理常数测量、深空导航、测地学等领域具有重要的应用。而这些应用均要求将光原子钟在某一特定光学波段的输出信号转换到其他光学波段或微波波段,从而进行精密测量和比对研究,还要求在转换过程中不能破坏光原子钟高频率稳定度、高频率精度的优异性能。因此高精度光学频率合成技术的研究意义重大。由于光学波段信号的频率值在1014 Hz量级,远大于电子元件的响应范围,所以现有的基于电子技术的微波频率合成方法很难直接应用于光学频率合成中。飞秒光学频率梳可在宽达一个光学倍频程的波段内同时输出许多等频率间隔的频率成分,这一频谱特性使其能够在不同波段的光频信号之间以及光频信号和微波信号之间建立联系,为进行不同光频之间的相互转换提供了便捷的桥梁。本论文研究了高精度、低噪声的光学分频技术,通过集成窄线宽飞秒光梳技术和传输振荡器技术,并提出消除微波频率噪声的光频自参考微波频率基准技术,首次实现了分频数可预置光学分频器。通过此高精度光学分频器与基于光学倍频效应的频率转换器之间的比对实验,本文证明了这一高精度光学分频器在频率转换过程中引入的频率不稳定度达到6×10-19(1秒积分时间),分频不确定度为1.4×10-21。该光学分频器的精度比目前最精确的光钟的精度还要好3个数量级,因此在对光钟信号进行分频时不会降低其频率精度,可满足世界上最好光钟的应用要求。基于此高精度光学分频技术,本文还将一套线宽为0.7 Hz、频率不稳定度达到1×10-15的1064 nm窄线宽稳频激光的频率精确转换到一套可大范围调谐的钛宝石单频连续激光器,实现了输出波长在700 nm-990nm范围内的光学频率合成器。该光学频率合成器能在700 nm-990 nm波段中任意指定频率处实现高精度单频窄线宽激光输出。本文将此光学频率合成器在778.6 nm波段的输出与另一台独立的778.6 nm窄线宽激光进行拍频测试,证明了此光学频率合成器输出激光的平均线宽达到1 Hz,频率不稳定度达到1.5×10-15(1秒积分时间),它主要受限于光学频率合成器的参考激光的线宽和频率稳定度。在此基础上,本文还实现了光学频率合成器在不同波段的多通道同时输出,并证明了该系统在多通道输出过程中引入的频率不稳定度为8×10-19,不同通道之间的频率比值不确定度为2×10-21。高精度光学频率合成技术的研究可为光钟应用提供必要的工具,同时为开展精密光谱和精密测量等领域的研究提供了有效的技术手段。
[Abstract]:The frequency instability and uncertainty of the optical atomic clocks have reached 10-18 orders of magnitude. They have important applications in the fields of basic physical constants, deep space navigation, geodesy and other fields. These applications require that the output signals of the optical atomic clocks be transferred to other optical or microwave bands in a particular optical band. Precision measurement and comparison study also require that the high frequency stability and high frequency accuracy of the optical atomic clock can not be destroyed during the conversion process. Therefore, the research of high precision optical frequency synthesis is of great significance. Because the frequency value of the optical band signal is at the magnitude of 1014 Hz, it is far larger than the response range of the electronic components, so the existing base The microwave frequency synthesis method in electronic technology is difficult to apply directly to the optical frequency synthesis. The femtosecond optical frequency comb can simultaneously output a number of frequency components with equal frequency intervals within a band of one optical frequency multiplier, which makes it able to be between the optical frequency signals of different bands, as well as the optical and microwave signals. In this paper, a high precision and low noise optical frequency division technology is studied in this paper. By integrating the narrow linewidth femtosecond combing technology and the transmission oscillator technology, the optical frequency reference frequency reference technology for eliminating the microwave frequency noise is proposed for the first time. Through comparison experiments between this high-precision optical frequency divider and frequency converter based on optical frequency multiplier effect, this paper proves that the frequency instability of this high precision optical frequency divider is 6 * 10-19 (1 second integral time), and the frequency division uncertainty is 1.4 * 10-21. The precision of the optical frequency divider is 3 orders of magnitude better than the precision of the most accurate clock. Therefore, the frequency accuracy of the clock signal will not be reduced, and the application requirement of the best clock in the world is met. Based on this high precision optical frequency division technique, a set of line width is 0.7 Hz and the frequency instability reaches 1 * 10. The frequency of the 1064 nm narrow line width and frequency stabilization laser of the -15 is accurately converted to a range of tunable titanium gem single frequency CW lasers. The optical frequency synthesizer of the output wavelength in the range of 700 nm-990nm is realized. The optical frequency synthesizer can achieve high precision single frequency narrow linewidth laser transmission at any specified frequency rate in the 700 nm-990 nm band. In this paper, the output of this optical frequency synthesizer in 778.6 nm band and another independent 778.6 nm narrow line width laser is tested. It is proved that the average line width of the output laser of the optical frequency synthesizer reaches 1 Hz and the frequency instability reaches 1.5 * 10-15 (1 second integration time). It is mainly limited to the reference of the optical frequency synthesizer. On the basis of this, the multi channel simultaneous output of the optical frequency synthesizer at different wavelengths is realized, and the frequency instability of the system is 8 * 10-19, the frequency ratio uncertainty between different channels is 2 * 10-21. high precision optical frequency coincidence. The research of technology can provide the necessary tools for the application of optical clock, and also provide effective technical means for the research of precision spectroscopy and precision measurement.
【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN74

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