Laser frequency locking with low pump field saturated absorption spectroscopy
Laser frequency locking with low pump field saturated absorption spectroscopy
复制标题
低泵浦场饱和吸收光谱激光锁频
DOI：
10.1631/jzus.a1700142
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发表时间：
2018-02
期刊：
影响因子：
--
通讯作者：
Lin Qiang
中科院分区：
文献类型：
--
作者：
Liang Shang-qing;Xu Yun-fei;Lin Qiang
近年来，许多基于量子效应的系统已被应用于精密测量。Swarm卫星携带的激光泵浦氦4绝对标量原子磁力计用于测量地球磁场强度（Fratter等人，2016）。中国在2016年发射了第一台冷原子钟，其中稳频激光系统非常重要（Li等人，2016年）。开发了一种用于现场应用的紧凑型冷原子重力仪（Bidel等人，2013年）。这些系统中的大多数都需要频率稳定的激光系统，它们被放置在移动平台上。这些平台的振动是激光频率的重要噪声源，因为在振动条件下可能发生可调部件的长期变化（Liu等人，2013年）。有许多激光光谱方案可以用作频率锁定的参考（Debs等人，2008; Martins等人，2010; Yang等人，2010; Biesheuvel等人，2013年; Wan等人，2016）。饱和吸收光谱法是在精密测量实验中用作激光频率锁定参考的这些方便方案之一（Debs等人，2008年）。在该方案中，通过调整反射镜的位置，使泵浦场和探测场重合。因此，泵浦光方向的长期漂移可能由于振动环境中反射镜的变化而发生。长期漂移对激光频率锁定产生负面影响。为了避免分立反射镜产生的振动噪声，提出了一种无需附加反射镜的低泵浦场饱和吸收光谱。探测光束从蒸气室的内表面反射的光被用作泵浦场。低泵浦场饱和吸收光谱图如图1所示。蒸气室的材料是K9玻璃，表面上没有涂层。玻璃的反射率约为10%，电池的长度约为7 cm。实验如图2所示。通过商用半导体二极管激光器Toptica DL 100产生直径为4 mm的50 mW 795 nm激光器，该激光器被调谐到Rb原子的Fg=3到Fe的跃迁。光穿过光隔离器，然后被楔形棱镜反射。棱镜表面镀有减反射膜，每一面的反射率均为1%。从第一表面反射的激光束垂直于蒸气室表面并用作探测场。另一个反射光束的方向与探测场的方向之间的夹角为20°。因此，饱和吸收光谱仅存在于探测场的信号中。另一个反射场作为参考场，用于消除多普勒吸收背景。信号以差分模式检测，并由系数为10 V/A的前置放大器放大。放大的信号被发送到锁定放大器SR 830。浙江大学学报-理科A级（应用物理与工程）ISSN 1673- 565 X（印刷版）; ISSN 1862-1775（网络版）jzus@zju.edu.cn www.springerlink.com www.jzus.zju.edu.cn
In recent years, many systems based on quantum effects have been applied to precision measurement. A laser pumped helium 4 absolute scalar atomic magnetometer which is carried by the Swarm satellite is used to measure the earth magnetic field intensity (Fratter et al., 2016). China launched the first cold atomic clock in 2016, in which frequency stabilized laser systems were very important (Li et al., 2016). A compact cold atom gravimeter was developed for field application (Bidel et al., 2013). Most of these systems, which require frequency stabilized laser systems, are placed on moving platforms. The vibration of these platforms is an important noise source to the laser frequency because the long-term changes of adjustable parts may occur under the vibration condition (Liu et al., 2013). There are many laser spectroscopy schemes that can be used as a reference for frequency locking (Debs et al., 2008; Martins et al., 2010; Yang et al., 2010; Biesheuvel et al., 2013; Wan et al., 2016). Saturated absorption spectroscopy is one of these convenient schemes used as reference for laser frequency locking in precision measurement experiments (Debs et al., 2008). In this scheme, reflecting mirrors are adjusted for the coincidence of the pump field and probe field. Therefore, long-term drift of the pump light direction may occur from the change in mirrors in a vibration environment. The long-term drift causes a negative effect on laser frequency locking. To avoid the vibration noise from separated reflecting mirrors, we present a low pump field saturated absorption spectroscopy without additional reflecting mirrors. The reflected light of the probe beam from the inner surface of the vapor cell is applied as the pump field. The diagram of the low pump field saturated absorption spectroscopy is shown in Fig. 1. The material of the vapor cell is K9 glass with no coating on the surfaces. The reflectivity of the glass is about 10% and the length of the cell is about 7 cm. The experiment is shown in Fig. 2. A 50 mW 795 nm laser of 4 mm diameter which is tuned to the transitions Fg=3 to Fe of Rb atoms is generated by a commercial semiconductor diode laser Toptica DL 100. The light passes through an optical isolator and is then reflected by a wedge prism. The prism is coated with anti-reflective films and the reflectivity of each surface is 1%. The laser beam reflected from the first surface is normal to the vapor cell surface and acts as the probe field. The angle between the direction of the other reflected beam and that of the probe field is 20°. Therefore, the saturated absorption spectroscopy only exists in the signal of the probe field. The other reflected field acts as the reference field for eliminating the Doppler absorption background. The signals are detected with the differential mode and amplified by a pre-amplifier with a factor of 10 V/A. The amplified signal is sent to a lock-in amplifier SR 830. The Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering) ISSN 1673-565X (Print); ISSN 1862-1775 (Online) www.jzus.zju.edu.cn; www.springerlink.com E-mail: jzus@zju.edu.cn
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影响因子：
3.8
作者：
J. Biesheuvel;D. Noom;E. Salumbides;K. Sheridan;W. Ubachs;J. Koelemeij
通讯作者：
J. Biesheuvel;D. Noom;E. Salumbides;K. Sheridan;W. Ubachs;J. Koelemeij
影响因子：
1.9
作者：
W. S. Martins;M. Grilo;Manoel Brasileiro;O. di Lorenzo;M. Oriá;M. Chevrollier
通讯作者：
W. S. Martins;M. Grilo;Manoel Brasileiro;O. di Lorenzo;M. Oriá;M. Chevrollier
影响因子：
4
作者：
Bidel, Yannick;Carraz, Olivier;Bresson, Alexandre
通讯作者：
Bresson, Alexandre
影响因子：
1.9
作者：
Debs, J. E.;Robins, N. P.;Close, J. D.
通讯作者：
Close, J. D.
影响因子：
--
作者：
Xiaoquan Song;Chao-Kwai Chen;Bingyi Liu;Jin-Bao Xia;S. Stanic
通讯作者：
Xiaoquan Song;Chao-Kwai Chen;Bingyi Liu;Jin-Bao Xia;S. Stanic