Relativistic photonic band gap mirror on chip
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.