稀土法拉第磁光玻璃研究新进展

稀土法拉第磁光玻璃是一种新型的功能材料,因其各向均匀性好、磁光性能优异、成本低廉而在光纤通信和传感等领域有着广阔的应用前景.介绍了磁光玻璃法拉第效应的基本原理;讨论了稀土离子种类及其浓度、基质玻璃、入射波波长、电子有效跃迁波长和绝对温度对法拉第磁光效应的影响;总结了磁光玻璃的制备方法和当前磁光玻璃研究中存在的问题.     

探知铷原子420nm精细能级结构的一种方法

本文通过研究针对V型能级结构的原子中弱振子强度跃迁谱线,提供一种速度转移激光光谱测量其精细能级结构的方法。利用高激发态不同原子能级跃迁产生谱线通过不同速度原子,转移到原子中低激发态跃迁线频率对应探测激光扫频记录的谱数据上。测量的速度转移谱具有亚多普勒的特征,而且是无交叉峰,又可以同时测量两个不同频率能级的光谱,这是传统饱和吸收谱做不到的。     

一种锁定半导体激光器频率的新方法

报道了一种实现半导体激光器频率锁定的新方法:通过交流磁场对法拉第反常色散光学滤波器(FADOF)的透射谱进行调制,将半导体激光器的频率锁定在FADOF的透射谱上。在B=1.76×10~(-2)T、T=120℃条件下,利用一阶导数稳频技术,测得1s和10s取样时间的频率稳定度分别为1.5×10~(-10)和5.8×10~(-11)。     

Er3Ga5O12法拉第效应的计算

用量子理论得出求解Er3Ga5O12磁光效应的近似方法。计算得到了在温度为4．2K，外磁场沿（100）、（111）两个方向的法拉第旋转角与外磁场的变化关系，其结果与实验值吻合较好。     

新型体全息窄带滤光器的光学特性研究

用紫外/可见分光光度计测定由DCG记录的透射式体全息窄带带阻滤光器的光谱特性,分析其滤波特性。测量结果分析表明,滤光器有较窄的带宽,其半宽度小于13nm,1/10宽度小于19nm。在400-800nm可见光区域,对其主谱线的相对透过率小于2%,其它谱线的相对透过率大于85%。对半导体泵浦激光器主谱线532.0nm有优良的滤光特性。     

法拉第两个电解定律的数理证明

本文通过对电解过程的深入研究，用数学的方法给出了法拉第的两个电解定律的理论性证明，从理论上给出了法拉第第二电解定律中普适恒量的本质解释，并且证明了它就是一个法拉第的倒数。本文还研究了阿弗加德罗常数与一个法拉第的电量及一个电子的电量之间的关系，给出了阿弗加德罗常数的一个更为精确的结果，即ＮＡ＝６．０２２１３６７（０３）×１０＾２３。由于纯粹由实验归纳而得到的两个法拉第电解定律是电化学理论的基础，因此     

半导体激光器稳频综述

在冷原子干涉实验中需要用激光冷却并操控原子,因此对半导体激光器频率的稳定性要求较高。由于半导体激光器本身线宽较大,功率稳定性差,还可能产生慢漂和跳模等现象,故需对半导体激光器进行稳频。本文介绍了饱和吸收谱稳频、波长调制稳频、调制光谱稳频、调制转移光谱稳频、双色激光稳频、频率电压转换稳频6种冷原子干涉实验中常用的稳频方法,分别阐述了各方法的原理、特点、适用领域,为半导体激光器的实际应用提供了参考。     

宽带可调谐光源瞬时波长测量方法研究

激光波长作为“米”基准的重要实现途径之一，其量值准确性在计量校准、精密测量以及光谱探测等领域具有十分重要的意义。目前基于标准物质吸收谱线的波长基准仅能用于单一波长的计量校准，对于宽带光源波长校准手段有限。本文开展宽带连续调谐激光波长校准技术研究，利用飞秒激光频率梳宽光谱、光频可溯源至原子频率标准、稳定性高的特点，对宽带调谐光源在调谐输出时的连续光波长进行测量，最终实现了1 nm带宽下可调谐激光器调谐输出过程中瞬时值的测量，并利用该结果对可调谐激光器在121 GHz带宽的调频非线性度进行了评价。     

多模式工作激光器的研究

目的:研究一台激光器多种模式工作的特性以及不同模式之间的转换。方法:设计一台双腔钛宝石激光器,采用双光束泵浦方式,通过锁模和光学元件的替换实现激光器的多模式工作。结果:连续运转状态下,两个激光腔的输出为可调谐连续输出;两个激光腔都进行色散补偿时,锁模激光器输出两列飞秒光脉冲;锁模状态下,只有一个激光腔进行色散补偿时,该激光腔输出飞秒光脉冲,而另外一个激光腔没有进行色散补偿,输出皮秒光脉冲。结论:多种模式工作的激光器适用于多种领域的研究与应用。     

结合塞曼效应与饱和吸收技术的DFB激光稳频系统的设计

本文介绍一种利用塞曼效应与饱和吸收相结合的技术提取激光频率误差信号的方法,利用数字PID控制技术,伺服反馈于DFB激光器的电流调制端实现慢环控制,模拟PI反馈于激光器FET电流控制端,实现快环控制,从而实现DFB激光器的稳频和线宽压窄。系统的激光频率锁定在铯原子D2饱和吸收谱线F=4→F’4,5交叉线上,频率峰-峰（p—p）起伏约为1．6MHz,相对频率起伏为4．5×10^-9,满足小型喷泉钟的使用要求。     

Nonlinear Faraday rotation for optical limitation

The possible use of the nonlinear Faraday effect for optical limitation of the laser power is investigated in a resonant Faraday medium placed between two crossed polarizers. The results are comparable with those obtained at strong magnetic fields as a result of the linear Faraday effect. Advantages of the method are the narrow bandwidth and the wide field of view. The investigations are interesting from the viewpoint of applications for optical sensor protection and automation of the experiment. All measurements are performed at the F(g) = 2 --> F(e) = 1 hyperfine structure transition of the 87Rb D1 line.     

Bi3+、Ce3+离子极大增强铁石榴石磁光法拉第效应微观机制研究

采用单离子晶格模型,以磁光量子理论计算了Bi 3+、Ce3+离子替代的稀土铁石榴石晶体中Bi3+、Ce3+离子的晶场能级,波函数及能态间电偶极跃迁几率,进而计算了Bi3+、Ce3+离子对法拉第旋转角θF的贡献,获得了与实验符合较好的计算结果,加深了对Bi3+、Ce 3+离子极大增强铁石榴石磁光效应微观机制的认识。,The split energy levels,occupation probabili ties,wave function and electrical dipole transition induced by crystal field and exchange interaction for the Ce3+ ions in Ce3+-substituted and the Bi3+ ions in Bi3+-substituted iron garnets at room temperature bas ed on quantum theory has been calculated.Furthermore,the calculation of the Fara day rotation contributed by the Ce3+ and Bi3+ ions has also been car ried out.The crystal field and the super-exchange interaction are two crucial f actors in determining the Faraday rotation.The theoretical results are in good t hose of experiments.     

基于双光子光谱的光学频率标准

首先概述了双光子跃迁的基本原理,然后介绍了连续光和脉冲光激发双光子跃迁的光学频率标准在实验上的进展,考虑到目前双光子光学频率标准的短期稳定度主要受限于本振,因此发展高功率低频率噪声的激光器用于抑制散粒噪声和互调制噪声是提高双光子光学频率标准短期稳定度的最直接有效的办法。最后介绍了双光子光学频率标准在科学上和工程上的应用。基于双光子直接光梳光谱的氢原子能级间距的测量已经成为测量里德堡常数和质子电荷半径的重要实验技术之一,在量子电动力学的检验中发挥着重要作用。双光子光学频率标准和微腔光梳的结合也为光学原子钟的小型化和集成化提供了新的可能。     

Effective dispersion in an inhomogeneously broadened single mode laser

Recently, we have been investigating the development of a superluminal ring laser, where finely tuned anomalous dispersion leads to an enhancement in the sensitivity of the laser frequency to a change in the cavity length, by as much as six orders of magnitude, for applications such as hypersensitive rotation sensing and accelerometry, as well as for gravitational wave detection. For such a laser, as well as other lasers that are used for precision metrology, the effective dispersion – manifested in the manner in which the lasing frequency varies as a function of a change in the cavity length due to the index induced by the medium under saturated gain corresponding to steady-state lasing – is of utmost significance. In determining the effective dispersion, the role of inhomogeneous broadening (IB) must be taken into consideration carefully. In this work, we consider an inhomogeneously broadened gain medium in a single mode optical cavity, and study the effective dispersion experienced by the lasing field. It is well known that the steady state index for such a laser cannot be expressed analytically. Previous studies have employed approximate models to interpret the effective dispersion, in two limits: IB is much larger than homogeneous broadening (HB), and IB is insignificant compared to HB. Here, we use an iterative but quickly converging numerical code to determine the exact behavior of the effective dispersion under all conditions, and show that the results agree with the expected behavior in these two limits. This technique paves the way for taking into account the effective dispersion in any inhomogeneously broadened laser, including the superluminal laser, in determining accurately its sensitivity to change in cavity length, as well as it quantum noise limited linewidth.     

Permanent magnets for Faraday rotators inspired by the design of the magic sphere

Faraday polarization rotators are commonly used in laser experiments. Most Faraday materials have a nonnegligible absorption, which is a limiting factor for high power laser optical isolators or for intracavity optical diodes. By using a stronger magnetic field and a shorter length of Faraday material, one can obtain the same polarization rotation and a reduced absorption. In this paper, we describe two permanent magnet arrangements that are easy to build and produce magnetic fields up to 1.7 T, substantially more than commonly used. The field homogeneity is largely sufficient for a 30 dB isolation ratio. We finally discuss the prospects for producing even larger fields with permanent magnets.     

Experimental study of a model digital space optical communication system with new quantum devices

We report a digital space optical communication system with new features both in the transmitting and in the receiving ends. The diode laser source is stabilized to within ±100 kHz by locking its frequency to the transmission peak of a Faraday anomalous dispersion optical filter (FADOF). The optical filter in the receiver uses two FADOF's that are linked to eliminate the multipeak structure and achieve a single-peak bandwidth of ~1 GHz. The detection sensitivity of this system is 23 times higher than that of a system with a traditional interference filter.     

TSAG-based cryogenic Faraday isolator

Thermooptical and magnetooptical properties of novel magnetoactive crystal terbium–scandium aluminum garnet were investigated at temperature range 80–300 K. It is shown that Verdet constant increases inversely proportional to temperature, and thermally induced depolarization, and the optical power of the thermal lens is reduced significantly with cooling from 290 K to 80 K. According to estimates, TSAG crystals in [1 1 1] orientation allow to create a cryogenic Faraday isolator provides a degree of isolation of 30 dB with the laser power exceeds ∼6 kW, it is estimated that the transition to the [0 0 1] orientation allows to provide degree of isolation of 30 dB at a laser power higher than 400 kW.     

主动光钟研究进展

自2005年至今，主动光钟经过了近20年的发展。主动光钟利用原子系综作为增益介质，其受激辐射可直接作为钟激光信号。因为主动光钟工作在坏腔区域，因此具有腔牵引抑制和窄线宽两个显著的优点，可以有效克服被动光钟存在的腔长热噪声问题。由于其优越的性能，主动光钟受到了国内外同行的广泛关注。根据实现方式不同，本文将主动光钟划分为原子束型主动光钟、基于激光冷却和光晶格囚禁的主动光钟、原子束及光晶格“复合型”主动光钟、法拉第主动光钟、离子阱囚禁型主动光钟以及热原子气室型主动光钟。对于不同类型的主动光钟，本文详细介绍了其实验及理论研究进展，并分析其优劣。最后，分析了主动光钟在精密测量领域的应用并展望了主动光钟的发展方向，为推动主动光钟的广泛应用提供借鉴。     

High‐Throughput,Protein‐Targeted Biomolecular Detection Using Frequency‐Domain Faraday Rotation Spectroscopy

A clinically relevant magneto‐optical technique (fd‐FRS, frequency‐domain Faraday rotation spectroscopy) for characterizing proteins using antibody‐functionalized magnetic nanoparticles (MNPs) is demonstrated. This technique distinguishes between the Faraday rotation of the solvent, iron oxide core, and functionalization layers of polyethylene glycol polymers (spacer) and model antibody–antigen complexes (anti‐BSA/BSA, bovine serum albumin). A detection sensitivity of ≈10 pg mL^?1 and broad detection range of 10 pg mL^?1 ? c_BSA ? 100 µ g mL^?1 are observed. Combining this technique with predictive analyte binding models quantifies (within an order of magnitude) the number of active binding sites on functionalized MNPs. Comparative enzyme‐linked immunosorbent assay (ELISA) studies are conducted, reproducing the manufacturer advertised BSA ELISA detection limits from 1 ng mL^?1 ? c_BSA ? 500 ng mL^?1. In addition to the increased sensitivity, broader detection range, and similar specificity, fd‐FRS can be conducted in less than ≈30 min, compared to ≈4 h with ELISA. Thus, fd‐FRS is shown to be a sensitive optical technique with potential to become an efficient diagnostic in the chemical and biomolecular sciences.     

Extraction and collection of laser photoionized neodymium ions measured by the multichannel Faraday cups

In order to effectively extract and collect photoionized ions generated by the laser irradiation of atomic beam, five sets of semicylindrical electrode pair were added to the ion extractor, and the obtained ion intensity distributions were measured by scanning multichannel Faraday cups. By applying potential difference between the additional electrodes up to about 1300 V for ion collection, the laterally broad distributions of the extracted ion beam were collected both vertically and horizontally, and the central ion beam flux was intensified.