Interfering Pulse Train Magnetometer

本项目是开发一种干涉脉冲串磁强计（IPTM），其传感器探头将位于光纤的尖端，环形激光器的尾部延伸。信号灵敏度比任何基于法拉第旋转的磁力计提高1000倍，这源于锁模激光腔内的相位到频率的转换。与现有的原子蒸汽磁强计（通常配有磁线圈和射频源）不同，该仪器只涉及激光和磁场传感器的共生。利用的原理是：(i)相干种群捕获，通过调整激光重复率实现；（ii）基于两列脉冲干涉的相位测量。实现了飞秒分辨率。知识优势：先前NSF支持的研究导致了一种相位测量技术，其中激光用作干涉仪。应用于两个腔内脉冲的相位差被转换成频率，比幅度更容易测量。与调幅广播相比，调频广播所带来的改进是相当的。两个脉冲之间的相位差是由施加在腔内传感器上的磁场产生的。最高的灵敏度是通过使用原子蒸汽来预测的，利用狭窄的暗线共振，通过将激光的重复率调整到超精细分裂的次倍来实现，因此绕过通常需要获得这种共振的外部RF源。对于1厘米的传感器，预测响应为1013 Hz/T，可以精确测量任何材料的磁性。最近的研究表明，铁磁材料可以有超快的响应。新仪器将使fs - resolved进行泵浦-探针实验成为可能，其中泵浦是从腔外发出的脉冲，两个探针是询问磁场的腔内圆极化脉冲。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/医学中的局部探针。更广泛的影响：这种跨学科的仪器将导致神经活动的新见解。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局部磁力计，而不是脑磁图传感器，后者不能在距离源3厘米以内工作。作为教育影响，将为该小组的博士生提供培训，并将项目成果纳入研究生课程（现代主题和光学实验室）。这些里程碑将在光学/生物学系列研讨会上进行讨论，新墨西哥大学光学科学/工程专业的所有学生都将参与其中。与往年一样，本科学生将通过REU入学。教师研究性教育（RET）的国家科学基金会资源将用于招收来自两所选定高中的教师参加该计划的夏季。这个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。新墨西哥大学是一所西班牙裔服务机构。

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.