自由载流子前向通过带间间接光子跃迁的反射。

Reflection from a free carrier front via an intraband indirect photonic transition.

机构信息

Institute of Optical and Electronic Materials, Hamburg University of Technology, Hamburg, 21073, Germany.

Department of Physics, Faculty of Science, Menoufia University, Menoufia, 32511, Egypt.

出版信息

Nat Commun. 2018 Apr 13;9(1):1447. doi: 10.1038/s41467-018-03862-0.

DOI:10.1038/s41467-018-03862-0

PMID:29654255

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5899136/

Abstract

The reflection of light from moving boundaries is of interest both fundamentally and for applications in frequency conversion, but typically requires high pump power. By using a dispersion-engineered silicon photonic crystal waveguide, we are able to achieve a propagating free carrier front with only a moderate on-chip peak power of 6 W in a 6 ps-long pump pulse. We employ an intraband indirect photonic transition of a co-propagating probe, whereby the probe practically escapes from the front in the forward direction. This forward reflection has up to 35% efficiency and it is accompanied by a strong frequency upshift, which significantly exceeds that expected from the refractive index change and which is a function of group velocity, waveguide dispersion and pump power. Pump, probe and shifted probe all are around 1.5 µm wavelength which opens new possibilities for "on-chip" frequency manipulation and all-optical switching in optical telecommunications.

摘要

光从运动边界的反射在基础研究和频率转换应用中都很有意义，但通常需要高泵浦功率。通过使用经色散工程设计的硅光子晶体波导，我们仅需在 6 ps 长的泵浦脉冲中使用 6 W 的片上峰值功率，就能够实现传播的自由载流子前沿。我们采用了同向传播的探针的带内间接光子跃迁，其中探针实际上从前沿向前方向逃逸。这种前向反射的效率高达 35%，并且伴随着强烈的频率上移，这大大超过了折射率变化所预期的频率上移，并且是群速度、波导色散和泵浦功率的函数。泵浦、探针和频移探针都在 1.5 µm 波长左右，这为光通信中的“片上”频率控制和全光开关开辟了新的可能性。