30 November 2011 Detection of extremely small polarization rotation angles based on magneto-optic modulation
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Proceedings Volume 8201, 2011 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems; 82012E (2011) https://doi.org/10.1117/12.907163
Event: International Conference on Optical Instruments and Technology (OIT2011), 2011, Beijing, Beijing, China
Abstract
We designed and built a measuring system to detect a very small optical rotation. The total measuring system consists of a laser, a Faraday modulator, a photo-detector, and a lock-in amplifier. To test the sensitivity of the system, we built another system to generate the small polarization rotation angle. The rotation-generating system includes a dense coil around a magneto-optic crystal, a power amplifier working at modulation frequency about 1 kHz. The rotationgenerating system can drive probe beam polarization by 2°due to the Faraday effect under 0-2 kHz modulation frequency. We monitor the frequency and amplitude of the modulating signal by observing the second harmonic signal received by the photo-detector. Some factors which influence the detection system have been analyzed experimentally to found the best working setup of the system. Recently we can detect an angle of magnitude at 10-6rad and the SNR of the output of the lock-in amplifier is above 331.The resolution of the angle detection is better than 10-7rad.
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Simiao Han, Simiao Han, Zongjun Huang, Zongjun Huang, Qiang Huang, Qiang Huang, Jiuxing Li, Jiuxing Li, Qiang Liu, Qiang Liu, Junhai Zhang, Junhai Zhang, Weimin Sun, Weimin Sun, } "Detection of extremely small polarization rotation angles based on magneto-optic modulation", Proc. SPIE 8201, 2011 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems, 82012E (30 November 2011); doi: 10.1117/12.907163; https://doi.org/10.1117/12.907163
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