Interfering Pulse Train Magnetometer

本计画将研制一干涉式脉冲序列磁力仪，其探头将位于光纤的尖端，环形雷射的尾端延伸。 与任何基于法拉第旋转的磁力计相比，信号灵敏度提高了1000：1，这源于锁模激光腔内的相位到频率的转换。 与现有的原子蒸气磁力仪相比，通常伴随着磁线圈和RF源，该仪器仅涉及激光和磁场传感器的共生。 所利用的原理是（i）通过调谐激光重复率实现的相干布居捕获和（ii）基于两列脉冲干涉的相位测量。 实现了飞秒分辨率。知识专长： 之前NSF支持的研究导致了一种相位测量技术，其中激光器被用作干涉仪。 应用于两个腔内脉冲的相位差被转换成频率，比振幅更容易测量。 与AM广播相比，FM广播带来的改善相当。 两个脉冲之间的相位差由施加到腔内传感器的磁场产生。 最高的灵敏度预测通过使用原子蒸气，利用窄暗线共振实现调谐的激光器的重复率的一个约数的超精细分裂，因此绕过外部RF源通常需要获得这样的共振。 1 cm传感器的预测响应为1013 Hz/T，可以准确测量任何材料的磁特性。 最近的研究表明，铁磁材料可以有超快的响应。 新仪器将使飞秒解析执行泵浦-探测实验成为可能，其中泵浦是从腔外发送的脉冲，两个探测器是询问磁场的腔内圆偏振脉冲。 该探针的局部性质是独一无二的：它将在封装原子蒸汽的光子光纤中小型化，作为生物学/医学中的局部探针应用。更广泛的影响：这种跨学科仪器将导致对神经活动的新见解。 该仪器将为化学家、材料科学家、生物学家或医学研究人员提供一个本地磁力计，而脑磁图传感器不能在距离源3厘米以内的地方工作。 作为教育影响，将为该小组的博士生提供培训，项目成果将纳入研究生课程（现代主题和光学实验室）。 这些里程碑将在光学/生物学研讨会系列中讨论，涉及UNM光学科学/工程课程的所有学生。与往年一样，本科生将通过REU入学。美国国家科学基金会的教师研究教育（RET）资源将用于在该计划的夏季月份招收两所精选高中的教师参与。该小组将继续欢迎来自不同背景的少数民族和新来者的研究生。 UNM是一个西班牙裔服务机构。

This project is to develop an Interfering Pulse Train Magnetometer (IPTM), sensor of which the probe will be located at the tip of a fiber, tail extension of a ring laser. A 1000:1 improvement in signal sensitivity over any magnetometer based on Faraday rotation stems from the conversion of phase to frequency inside a mode-locked laser cavity. As contrasted to existing atomic vapor magnetometer, usually accompanied by magnetic coils and RF sources, this instrument involves only a symbiosis of the laser and a magnetic field sensor. The principles exploited are (i) coherent population trapping, achieved by tuning the laser repetition rate and (ii) phase measurement based on the interference of two trains of pulses. A femtosecond resolution is achieved. INTELLECTUAL MERIT: Prior NSF supported research led to a phase measurement technique in which the laser is used as an interferometer. A phase difference applied to two intracavity pulses is converted into a frequency, easier to measure than amplitude. The improvement is comparable to that brought by FM radio as compared to AM broadcast. The phase difference between the two pulses is produced by the magnetic field applied to an intracavity sensor. Highest sensitivity is predicted through the use of atomic vapors, exploiting narrow dark line resonance realized by tuning the repetition rate of the laser to a submultiple of a hyperfine splitting, hence bypassing the external RF source usually required obtaining such resonances. With a predicted response of 1013 Hz/T for a 1 cm sensor, the magnetic properties of any material can be accurately measured. Recent work suggests that ferromagnetic materials can have an ultrafast response. The new instrument will make it possible to fs resolved perform pump-probe experiments, where the pump is a pulse sent from outside the cavity, and two probes are the intracavity circularly polarized pulses interrogating the magnetic field. The local nature of the probe is unique: it will be miniaturized in a photonics fiber encapsulating the atomic vapor for application as a local probe in biology/medicine.BROADER IMPACTS: This interdisciplinary instrument will lead to a new insight in nerve activity. This instrument will provide Chemists, Material Scientists Biologists or Medical researchers with a local magnetometer, as opposed to magnetoencephalography sensors that cannot operate closer than 3 cm from the source. As educational impact, training will be provided to the PhD students of the group, and project results will be incorporated in graduate courses (Modern topics and Optics Labs). The milestones will be discussed in Optics/Biology seminar series, involving all students of the Optical Science/engineering program of UNM. As in previous years, undergraduate students will be enrolled through the REU. The NSF resources of the Research Education for Teachers (RET) will be used to enroll the participation of teachers from two selective High Schools in the summer months of the program. This group will continue to welcome minorities and newcomers' graduate students from diverse background. UNM is a Hispanic serving institution.