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arXiv · 1810.03320

Efficient nitrogen-vacancy centers' fluorescence excitation and collection from micrometer-sized diamond by a tapered optical fiber

Dewen Duan·Guanxiang Du·Vinaya Kumar Kavatamane·Sri Ranjini Arumugam·Yan-Kai Tzeng·Huan-Cheng Chang·Gopalakrishnan Balasubramanian
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Abstract

Efficiently excite nitrogen-vacancy (NV) centers in diamond and collect their fluorescence significantly benefit the fiber-optic-based NV sensors. Here, using a tapered optical fiber (TOF) tip, we significantly improve the efficiency of the laser excitation and fluorescence collection of the NV, thus enhance the sensitivity of the fiber-optic based micron-sized diamond magnetic sensor. Numerical calculation shows that the TOF tip delivers a high numerical aperture (NA) and has a high fluorescence excitation and collection efficiency. Experiments demonstrate that using such TOF tip can obtain up to over 7-fold the fluorescence excitation efficiency and over15-fold the fluorescence collection efficiency of a flat-ended (non-TOF) fiber. Such fluorescence collection enhances the sensitivity of the optical fiber-based diamond NV magnetometer, thus extending its potential application region.

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Dewen Duan, Guanxiang Du, Vinaya Kumar Kavatamane, Sri Ranjini Arumugam, Yan-Kai Tzeng, Huan-Cheng Chang, Gopalakrishnan Balasubramanian. 2018-10-09. Efficient nitrogen-vacancy centers' fluorescence excitation and collection from micrometer-sized diamond by a tapered optical fiber. https://doi.org/10.1364/oe.27.006734

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