基于飞秒激光频率梳偏移的干涉法实验研究

Femtosecond optical frequency comb and stabilized lasers technology play important roles in the development of atom and molecular physics, metrology, communication systems and optical atomic clock. so that the derivative technique for absolute distance measurement by femtosecond optical frequency comb，which features in an advantage of high-speed，large-scale and high-precision,has become a worldwide research hotspots.. Use of a femtosecond laser significantly simplified and improved the accuracy of measuring optical frequencies due to the broadening of the emission spectrum of a self-modelocked laser generating octave-spanning frequency combs. Mixing low- and high-frequency wings of the spectrum made it possible to determine the shift of the frequency comb on the absolute frequency scale, to create a so-called f-2f-interferometer. If the intermode frequency of the comb is locked to the frequency of the microwave standard and the comb shift is measured relative to the zero frequency, then the entire range of values of frequency components of a femtosecond laser is known with relative accuracy, defined by the frequency standard. We propose and experimentally demonstrate the method of measuring of the comb-frequency shift for laser with mode locking with a wide spectrum of radiation which is less than an octave, by using Fabry-Perot.The use of a system, consisting of a frequency standard, a femtosecond synthesiser and an interferometer, allows one to create a uniform standard of time, frequency and length

飞秒光频梳和稳定激光技术的发展，对物理精密测量，原子分子结构的研究，测量学，光通讯系统和原子光钟的研究领域都扮演着非常重要的角色。由此衍生的飞秒光学频率梳绝对测距技术以其快速、大尺寸、高精度等优点己成为国际研究热点。. 采用飞秒激光可以明显简化和改进光学频率的测量准确性，这通过自锁模激光器产生倍频梳状发射光谱的一个八度音拉宽来实现。混合光谱的低频段和高频段使人们可以确定在绝对频率尺度内的频梳移动，用来创建一个所谓的F-B干涉仪。如果频梳的中间频率被锁定在微波标准，而频梳偏移值相对于零频率进行测量，就可以知道飞秒激光器频率分量值在整个范围的相对准确度，其值用标准频率来定义。本研究项目提出的测量方法所使用的F-B干涉仪系统中的频梳偏移激光器模式锁定在小于一个8度音拉宽的辐射范围内。该系统起飞秒合成器和干涉仪并与频率标准相容，用来可以创建通用标准时间、频率和长度。

飞秒光学频率梳的发明实现了光频和微波的高精度直接链接和不同光学频率标准之间的高精度链接，开拓了光场时域和频域同时精密操控的研究领域。飞秒光学频率梳具有带宽宽、高功率和稳定好的优点被广泛地应用于物理精密测量、航空航天、原子分子结构研究、测量学、高精度光谱学，光学原子钟，阿秒科学、天文学、量子信息处理和光通讯系统等研究领域。本项目在国家自然科学基金的支持下，围绕飞秒光学频率梳绝对距离测量技术进行了深入的研究和探索。主要研究内容包括以下几个方面：(1) 分析了现有各种绝对距离测量方法，研究了飞秒锁模激光重复频率和偏差频率的稳频方法，激光频率梳的原理 以及其在激光精密测量中的应用. (2)研究了由飞秒激光器、光学频率锁模仪和法布里-珀罗(Fabry-Perot)干涉仪组成的系统中的反射镜对飞秒激光光频梳偏移的影响。探讨了反射镜造成的色散及角偏移对光频梳偏移的影响. (3)在对飞秒激光光束质量因子进行理论研究的基础上，进行了相应的数据计算，给出了飞秒激光脉冲照射屏幕表面时所形成的环形光斑宽度的测量方法，设计了一套由飞秒激光器、透镜、介电材料玻璃屏幕所组成的实验平台。