Widely Tunable Distributed Bragg Reflectors Integrated into Nanowire Waveguides

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• 作者：Anthony Fu ; Hanwei Gao ; Petar Petrov ; Peidong Yang
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：15
• 期：10
• 页码：6909-6913
• 全文大小：316K
• ISSN：1530-6992

文摘

Periodic structures with dimensions on the order of the wavelength of light can tailor and improve the performance of optical components, and they can enable the creation of devices with new functionalities. For example, distributed Bragg reflectors (DBRs), which are created by periodic modulations in a structure鈥檚 dielectric medium, are essential in dielectric mirrors, vertical cavity surface emitting lasers, fiber Bragg gratings, and single-frequency laser diodes. This work introduces nanoscale DBRs integrated directly into gallium nitride (GaN) nanowire waveguides. Photonic band gaps that are tunable across the visible spectrum are demonstrated by precisely controlling the grating鈥檚 parameters. Numerical simulations indicate that in-wire DBRs have significantly larger reflection coefficients in comparison with the nanowire鈥檚 end facet. By comparing the measured spectra with the simulated spectra, the index of refraction of the GaN nanowire waveguides was extracted to facilitate the design of photonic coupling structures that are sensitive to phase-matching conditions. This work indicates the potential to design nanowire-based devices with improved performance for optical resonators and optical routing.