Relativistic photonic band gap mirror on chip

在这个方案中，我们首次起草了基于光子晶体的相对论反射镜的实验实现路线，这种反射镜可以用来戏剧性地操纵光信号的频率和带宽。为此，我们建议实现一种耦合光子晶体波导系统，并将其运行在简并点附近，也称为狄拉克点。这种简并性可以通过泵浦脉冲的双光子吸收产生的自由载流子来解除。被提升的简并度将构成一个局域光子带隙，该带隙的空间边界将随着泵浦脉冲的群速度而移动。在局域带隙内的某一频率处的光信号会随着频移和带宽的变化而发生反射。提出的系统将允许在集成光学技术中利用相对论反射镜。该项目的主要目标是实现在狄拉克点附近具有小传播损耗的耦合波导，以及有效地将信号和泵浦脉冲注入到波导系统中。然后，计划对相对论光子带隙前沿的信号反射进行动态实验。预计反射后的信号时长可以压缩10-100倍，而不会出现明显的频移。光子带隙前沿的实验实现也将使其他相关效应的研究成为可能，例如在前沿自发产生光子。该项目是在由德国研究基金会和中国国家自然科学基金组织的中德联合征集方案框架内提交的。本次活动将与广州中山大学的李俊涛博士、蔡新伦博士、中国博士合作进行。SYSU的项目将集中在光刻和离子刻蚀工艺的设计优化以及低损耗耦合光子晶体波导的制造上。挑战是为了纳米精度而调整制造工艺。汉堡工业大学(TUHH)的申请者将设计芯片的结构并测量芯片上的相对论效应。

In this proposal we first time draft the route towards experimental realisation of photonic crystal based relativistic mirrors which can be used to dramatically manipulate the frequency and bandwidth of optical signals. For that we propose to realise a system of coupled photonic crystal waveguides and operate it close to the point of degeneracy, also called Dirac point. This degeneracy can be lifted by free carriers generated via two photon absorption of the pump pulse. The lifted degeneracy will constitute a local photonic band gap, where the spatial boundary of this band gap will move with the group velocity of the pump pulse. The optical signal at a frequency within the local band gap will experience reflection with frequency shift and bandwidth change. The proposed system will allow an exploitation of the relativistic mirror in integrated optics technology. The main goals of this project are the realisation of coupled waveguides with small propagation loss close to the Dirac point, as well as efficient injection of the signal and pump pulses into the waveguide system. Afterwards the dynamic experiments of signal reflection from relativistic photonic band gap front are planned. It is expected that the signal duration can be compressed by 10-100 times after reflection without significant frequency shift. Experimental realisation of photonic band gap fronts will also make possible the investigation of other related effects, e.g. spontaneous generation of photons at the front.The project is submitted in the frame of the Joint Sino-German call for proposals organised by the German Research Foundation (DFG) and the National Natural Science Foundation of China (NSFC). It will be conducted in cooperation with Dr. Juntao Li and Dr. Xinlun Cai from Sun Yat-sen University (SYSU), Guangzhou, China. The project at SYSU will concentrate on the design optimization for lithography and ion etching processes and on fabrication of low loss coupled photonic crystal waveguides. The challenge is the adjustment of manufacturing processes for nanometer precision. The applicants at Hamburg University of Technology (TUHH) will design the structures and measure relativistic effects on chip.