Dispersion and Optical Drag Effects in Rotating Semiconductor Ring Lasers

0524509Osinski说明性摘要。将标准理论方法应用于环形激光器，并不能对色散很大的介质(如半导体材料)中的Sagnac效应的大小给出明确的定量答案。一般通过菲涅耳-菲佐公式给出的折射率和阻力系数来考虑介质的影响。在大多数激光陀螺中，环的有效介质的材料色散可以忽略不计。相比之下，基于半导体介质的紧凑型单片集成陀螺的色散效应是显著的，阻力系数问题的实质是对旋转运动的修正是有问题的。Fresnel-Lorentz处理中的阻力系数包含与色散有关的贡献lnn/lnl。在气体或固态介质中，它对可观察到的光学拖曳进行了非常小的修正。在半导体中，色散项lnn/lnl足够大，不仅影响净阻力效应的大小，甚至影响净阻力效应的符号。然而，当这一项被包括在环形激光器的模型中时，陀螺响应对平移运动变得敏感，这与爱因斯坦的相对论原理相矛盾。这个问题是由E.Post在1967年首次注意到的，他为了遵守相对论原理，在某种程度上任意地将色散项排除在阻力系数之外。到目前为止，还没有对Post的方法进行实验验证。最近，PI已经成功地研制出了具有较大(~1 cm)腔的单片集成半导体环形激光器(SRL)，并能够观察到独立激光器的模式拍频光谱。这为实验研究色散项对Sagnac效应的贡献提供了可能。将进行实验以精确确定SRL中的陀螺系数，并将结果与各种理论预测进行比较。如果没有这些测试，就不能可靠地计算基本陀螺比(与Sagnac相关的频率分裂与角自转速度的比率)。尽管SRL具有很好的紧凑性和低功耗，但由于以前设计中的缺陷，SRL尚未被用于陀螺应用。这个项目将为最终阐述SRL的旋转传感问题提供科学基础：如何避免频率锁定，增强陀螺因子，排除多余的噪声，并应用新的方法，如慢光/快光概念。由Osinski教授领导的新墨西哥大学(UNM)小组在半导体环形激光器的物理和技术方面拥有最佳的经验和大量的成果。这项拟议的工作有望克服目前集成光电子器件的局限性。这一结果将对旋转运动的基本物理(非惯性框架和系统)以及旋转传感器和导航陀螺仪的应用物理具有重要意义。这个项目的结果有望导致基于慢/快光的新一代旋转传感器。Sagnac效应在单片集成SRL中的首次演示，加上对色散对效应大小贡献的结论性研究，将为高性能、小尺寸、低成本的旋转传感器开辟新的机会，具有广泛的新应用，从机器人和玩具业到高精度导航级陀螺仪。北卡罗来纳州立大学是卡内基大学的博士/研究机构，为少数族裔机构服务的拉美裔学生(37.5%的主校区学生是少数族裔学生)。将把重点放在教育和人力资源开发上，方法是让研究生和本科生参与该项目，并将在该项目期间学到的新知识纳入与该提案主题直接相关的研究生课程。将努力让少数群体成员以及妇女参与这一项目。拟议的项目将为学生创造一个有吸引力的环境，这些学生得到UNM现有的其他主要项目的支持，这些项目面向少数族裔学生，致力于培训新一代研究科学家和工程师。

0524509OsinskiNarrative Summary. Application of standard theoretical approach to ring lasers does not give a clear quantitative answer on the magnitude of the Sagnac effect in a medium with substantial dispersion (such as in semiconductor materials). Generally, the influence of the medium is accounted for through the refractive index and the drag coefficient ad given by the Fresnel-Fizeau formula. In most laser gyros, the active medium of the ring has negligible material dispersion. In contrast, dispersion effects are expected to be substantial in compact monolithically integrated gyros based on semiconductor media.The essence of the problem of the drag coefficient is its questionable modification for rotational motion. The drag coefficient in the Fresnel-Lorentz treatment contains a dispersion-related contribution lnn/lnl. In gas or solid-state media, it gives a very small correction to the observable optical dragging. In semiconductors, the dispersion term lnn/lnl is large enough to influence not only the magnitude, but even the sign of the net drag effect. However, when this term is included in modeling of the ring laser, the gyroscopic response becomes sensitive to translational motion, in contradiction with Einstein's relativity principle. The problem was first noted in 1967 by E. Post, who somewhat arbitrarily excluded the dispersion term from the drag coefficient in order to comply with the relativity principle. Until now, no experimental verification of Post's approach was attempted.Recently, the PI has succeeded in development of monolithically integrated semiconductor ring lasers (SRLs) with relatively large (~1 cm) cavity and were able to observe the mode beating spectra from independent lasers. This opens up a possibility to perform experimental investigation of the question about contribution of dispersion term into the Sagnac effect. Experiments will be performed for precise determination of the gyroscopic coefficient in SRLs and the results will be compared with various theoretical predictions. Without these tests, the fundamental gyroscopic ratio (the ratio of Sagnac-related frequency splitting to the angular rotation rate) cannot be reliably calculated.Intellectual Merit Criterion. In spite of their promising compactness and low power consumption, SRLs have not yet been used for gyro applications, primarily due to flaws in previous designs. This project will provide scientific base for ultimate elaboration of rotation sensing problem using SRLs: how to avoid the frequency lock-in, enhance the gyro-factor, exclude excess noise, and apply novel approaches such as slow/fast light concept.The University of New Mexico (UNM) group led by Prof. Osinski has the best experience and numerous results in physics and technology of semiconductor ring lasers. The proposed work holds promise of overcoming the current limitations for integrated optoelectronic devices. The results will be important for fundamental physics of rotational motion (non-inertial frames and systems) and also for applied physics of rotation sensors and navigation gyroscopes. The results from this project are expected to lead to a new generation of rotation sensors based on slow/fast light.Broader Impacts Criterion. First demonstration of Sagnac effect in monolithically integrated SRLs coupled with conclusive studies of dispersion contribution to the magnitude of the effect will open up new opportunities for high performance, small size, low cost rotation sensors with a wide range of novel applications, ranging from robotics and toy industry to high-accuracy navigation-grade gyros.UNM has a dual commitment to excellence in research and to education opportunities for minorities and diverse society. UNM is Carnegie Doctoral/Research - Extensive and Hispanic Serving Minority Institution (37.5% of main campus enrollment are minority students). Emphasis will be placed on education and human resource development via involvement of graduate and undergraduate students in the project, and incorporation of the new knowledge gained during this project into graduate-level courses directly related to the subject of this proposal. Efforts will be made to engage members of minority groups as well as women in this project. The proposed project will create an attractive environment for students supported by other major programs already in existence at UNM that target minority students and are devoted to training of a new generation of research scientists and engineers.