【作者】 马瑞；

【导师】 罗斌；

【作者基本信息】 北京邮电大学 ， 电子科学与技术， 2022， 硕士

【摘要】 法拉第反常色散滤光器(Faraday anomalous dispersion optical filter,FADOF)是一种基于原子共振特征线在磁场条件下发生的反常色散效应实现的原子滤光器,其具有高透射率、超窄带宽、大视场角以及高噪声抑制等优点,可以极大地满足众多场景下的滤光需求。传统FADOF通常采用加热原子气室的方式来获得原子蒸气,这使得其存在一定的限制,如常温无法正常工作、对环境温度较为敏感等;另外,对于激发态(Excited state,ES)FADOF来说,除加热外还需要使用额外的泵浦激光器制备激发态原子蒸气,这极大地复杂化了 ES-FADOF的实现。针对上述问题,本论文进行了如下研究:1.完成了空心阴极灯型基态法拉第反常色散滤光器的搭建与研究。采用空心阴极灯(Hollow cathode lamp,HCL)替代FADOF结构中的原子气室(Vapor cell,VC),其特殊的“溅射”方式能够获得足够的原子蒸气建立滤光过程。使用铷元素空心阴极灯搭建的工作波长为780 nm的基态FADOF在室温条件下能够正常进行工作,在电流为18 mA、磁场值为260 G时,透射谱的峰值透射率达到29%;使用ElecSus程序计算了 VC-FADOF的透射谱,进行了 HCL-FADOF与VC-FADOF之间的横向对比。2.研究了空心阴极灯型法拉第反常色散滤光器温度与时间特性。在搭建的基态HCL-FADOF基础上,采用半导体制冷片实现空心阴极灯温度的控制,模拟其所处环境温度的变化。在环境温度为-5℃时,FADOF能够稳定工作,并且在环境温度变化了25℃(-5℃到20℃)的情况下,HCL-FADOF保持着较好的工作稳定性;针对HCL的预热时间,研究了 HCL-FADOF的启动特性,并进行了与VC-FADOF启动特性的横向对比。3.完成了空心阴极灯型激发态法拉第反常色散滤光器的搭建与研究。考虑空心阴极灯内部具备高动能的粒子与阴极材料原子之间发生碰撞效应时,能够使得一部分原子能够被激发,因此其能够进行激发态原子蒸气的制备。基于此,使用铷元素空心阴极灯构建了工作波长为1529nm的ES-FADOF,对其相关工作特性进行了详细研究。本实验搭建的激发态FADOF具有无需加热并且不需要额外泵浦激光器的特点,空心阴极灯的使用简化了 ES-FADOF的结构并且降低了实现难度。实验中测量了 ES-FADOF随着磁场、电流的变化情况,在电流为20mA、磁场值为214G时,透射谱的峰值透射率为1.5%;考虑1529 nm处于通信波段,使用品质因数FOM对滤光器的性能进行了衡量。更多还原

【Abstract】 Faraday anomalous dispersion optical filter(FADOF)is an atomic filter based on the anomalous dispersion effect occurring under the external magnetic field conditions,which has the advantages of high transmittance,ultra-narrow bandwidth,large field of view and high noise suppression,and can greatly meet the filtering needs in various scenarios.Conventional FADOF usually heating the atomic vapor cell to obtain atomic vapor,which has several limitations,such as cannot work at room temperature and being sensitive to ambient temperature;In addition to the above limitations,an additional pump laser is required to prepare the excited state saturated vapor for the excited state(ES)FADOF,which greatly complicates the implementation of the ES-FADOF.1.Completed the construction and research of a ground state Faraday anomalous dispersion filter based on the hollow cathode lamp.A hollow cathode lamp(HCL)is used instead of the atomic vapor cell(VC)to address the limitations of the VC-FADOF,which is able to obtain enough atomic vapor for establish the filtering due to its special"sputtering"method.The ground state FADOF with an operating wavelength of 780 nm,constructed using a rubidium hollow cathode lamp,is able to operate normally at room temperature,and the peak transmittance can reach 29%at a current of 18 mA and a magnetic field of 260 G.The transmission spectrum of the VC-FADOF was calculated using the ElecSus,and a crosssectional comparison between the HCL-FADOF and the VC-FADOF was performed.2.The Thermal and temporal characteristics of Faraday anomalous dispersion optical filters based on a hollow cathode lamp were investigated.A semi-conductor cooler is added to the established ground-state HCL-FADOF to simulate the change of the ambient temperature to achieve the adjustment of the HCL temperature.The HCLFADOF can work stably at an ambient temperature of-5℃,and can maintains a great stability when the ambient temperature changes by 25℃(-5℃ to 20℃).The temporal characteristics of the HCL-FADOF were measured for the warm-up time of the HCL,and a side-by-side comparison with the temporal characteristics of the VC-FADOF was performed.3.The construction and research of an excited state Faraday anomalous dispersion optical filter based on the hollow cathode lamp was completed.Considering the collisions between the high kinetic energy particles inside HCL and the atoms of cathode materials,a part of atoms can be excited,thus it can enable the preparation of excited state atomic vapor.An ES-FADOF with an operating wavelength of 1529 nm was constructed by using a rubidium hollow cathode lamp,and its characteristics were investigated in detail.The ES-FADOF constructed in this experiment has the feature of heating-free and pump-free,and the use of HCL greatly simplifies the structure of ES-FADOF and reduces the implementation difficulty.The peak transmittance can reach 1.5%at a current of 20 mA and a magnetic field of 214 G.Since 1529 nm is in the communication band,the performance of the filter is measured using the quality factor FOM.更多还原