Interfering Pulse Train Magnetometer

本项目是开发一种干涉脉冲列阵磁强计(IPTM)，其传感器的探头将位于光纤的尖端，环形激光器的尾部延伸。与任何基于法拉第旋转的磁强计相比，1000：1的信号灵敏度提高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强计通常伴随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。所采用的原理是(I)相干布居俘获，通过调节激光重复频率来实现；(Ii)基于两串脉冲的干涉来进行相位测量。达到了飞秒级的分辨率。智力优势：之前美国国家科学基金会支持的研究导致了一种将激光用作干涉仪的相位测量技术。施加到两个腔内脉冲的相位差被转换成比幅度更容易测量的频率。与调频广播相比，这种改进可以与调频广播相媲美。这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。通过使用原子蒸气预测最高的灵敏度，利用通过将激光的重复频率调到超精细分裂的亚倍数来实现的窄暗线共振，从而绕过通常需要获得这种共振的外部射频源。1厘米传感器的预测响应为1013赫兹/T，可以准确地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。这台新仪器将使我们有可能进行抽运-探测实验，其中抽运是从腔外发出的脉冲，两个探头是询问磁场的腔内圆偏振脉冲。探测器的局部性质是独一无二的：它将被微型化在封装原子蒸气的光子光纤中，作为局部探测器应用于生物/医学。BROADER影响：这种跨学科的仪器将导致对神经活动的新洞察。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本地磁力计，而不是磁脑图传感器，其工作距离震源不能超过3厘米。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讨论，参加研讨会的有新墨西哥大学光学科学/工程专业的所有学生参加。与往年一样，本科生将通过REU招生。教师研究教育(RET)的NSF资源将用于招收两所重点高中的教师在该计划的暑期几个月参加该计划。这一群体将继续欢迎来自不同背景的少数族裔和新来者的研究生。UNM是一家西班牙裔服务机构。

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.