光波干涉采样示波器

Interferometric sampling oscilloscopes for light waves

光频梳技术是本世纪初随着飞秒激光技术、非线性光学的飞速发展应运而起的一项重要的精密频率测量技术。它跨越了射频和光频电磁波谱之间长期存在的技术鸿沟,通过频率和相位的相干关系将二者巧妙的衔接,在时间频率标准、精密光谱计量以及基础物理学常数的高精度测量等领域具有举足轻重的应用价值。从光频梳的基本原理出发,解释了光频梳技术基本概念,稳定工作的光频梳以及作为高精密的频率测量技术,光频梳主要的应用领域等。同时回顾了作者研发光频梳技术的初衷,即用于研究氢原子的精密光谱,验证量子电动力学理论,提高里德堡常数和质子电荷半径等物理学基本常数体系的测量精度。介绍了通过双光频梳实现高精密的光谱直接测量技术,包括该技术的原理以及在气体分子精密光谱测量方面的应用,举例说明了基于双光频梳的光谱直接测量技术在频率分辨率和灵敏度方面相对于传统光频梳表现出来的显著优势。实验验证了单光子水平的光频梳光谱测量可行性,指出其在极紫外或甚至在软x射线这些产生少量光子的应用领域的应用前景。最后介绍了微小区域实现厘米级尺寸的光学腔的脉冲激光的激发、片上稳定的双光频梳实现等微型光频梳和片上光谱系统集成等关键技术和解决方案,并分析了片上光频梳光谱测量系统的发展和应用前景。

With the rapid development of femtosecond laser technology and nonlinear optics at the beginning of this century,optical frequency comb technology has become an important precision frequency measurement technology.It connects the radio and optical frequency realm by inching through the vast frequency gap via the coherent relationship between their separated frequencies and phases,which has a significant application value in the fields of time-keeping and frequency standards,precision spectral metrology and constants measurement in fundamental physics.Starting from the basic principle of an optical frequency comb,this paper discusses several basic concepts of the technology:the definition of optical frequency comb technology,the mechanism to obtain a stable optical frequency comb and the main applications of optical frequency combs as a high-precision frequency measurement technology.The original intention of developing the optical frequency comb technology is reviewed:to study the precise spectra of hydrogen atoms,to verify the theory of quantum electrodynamics,and to improve the measurement accuracy of the basic constants in physics,such as the Rydberg constant and proton charge radius.Secondly,the paper introduces the principle of direct frequency comb spectroscopy,which is based on a dual-optical frequency comb,and its application in the precise spectral measurement of gas molecules.It illustrates that this technique has significant advantages in frequency resolution and sensitivity compared with the conventional optical frequency comb technology based on a single frequency comb.The feasibility of the direct frequency comb spectroscopy at the single photon level is experimentally verified,and it is pointed out that it will have a very important application prospect in the extreme ultraviolet or even in the soft X-ray application fields which produce a small number of photons.Finally,the author introduced the realization of the centimeter sized optical cavity in a micro sized area and on-chip and stable dual-optical frequency combs are introduced.The development and application prospects of on-chip optical frequency comb spectral measurement system are also discussed.