波长量级定向发射的低阈值微盘激光器的基础研究

With the rapid progess on the eccnomy, enviromental pollution and energy crisis have become a serious problem for our country and obstacled the sustainable development. Thus energy-saving and enviroment protection is one of the strategic objectives of the national 12th five-year plan to achieve the eccnomic transformation and personal income growth. As the key element of optical storage, optical computing, integrated optics, laser printing, and optical interconnect, micro-laser also faces the challenging from the new concept of green eccnomy, e.g., the energy consumption must be significantly reduced while maintianing the unique laser properties such as unidirectional outputs and ultra-low threshold. However, the regular microlasers, especially the wavelength-scale lasers with lower energy consumption, always have a trade-off between the unidirectional emission and high Q factors. Some designs with unidirecitonal outputs are associated with the serious Q-spoiling, whereas the high Q ones have nearly isotropic outputs. Therefore, the breakthrough in both concepts and technologies is required and essential. In this project, based on our former studies on microlasers, we will focus on the formation of ultra-low threshold unidirectional laser emission. By introducing the mode coupling theory and the field pattern reconstruction, we will be able to obtain unidirectional emission from ultrahigh Q resonances that have non-directional outputs initially. Our new mechanism and the corresponding ultra-low energy consumption wavelgnth-sacle lasers will shed light on the applications of energy-saving on-chip coherent light sources and quantum light sources.

发展低能耗绿色产业以实现国家经济转型、国民收入增长是我国十二五期间的重大战略目标之一。作为一种广泛应用的关键元件，微型激光器也面对着严峻挑战- - 即在保持现有激光特性的同时完成降低能耗的目标。对于微型激光腔体设计而言，尤其在低能耗所需要的波长量级的小型腔内，光的能耗降低和激光的定向发射等性质存在一定的矛盾：单方向发射的微腔的Q值很低，而高Q值微腔一般不存在单向出射。通过本项目的实施，申请人计划在原有的微型激光器研究的基础上，通过理论设计和工艺改进两个方面，开展低能耗定向发射的半导体激光器的研究。通过模式耦合带来的模场的相互作用，设计、制备出一种具有高Q值（低阈值）、单向发射的波长量级或亚波长量级的微型激光器，进而揭示出波长量级低能耗激光器的设计机制，为低能耗集成激光光源以及量子光源的发展奠定基础。

本项目针对微型谐振腔很难存在高品质因子和定向发射共存的难题展开研究，得到了以下几个方面的研究成果。1）研究了微腔内的模式耦合，首次提出了利用模式耦合降低光学微腔内的动态隧穿的新机制，从而提高了微腔的品质因子，并提出了一种利用远场发射观察动态隧穿抑制过程（coherent destruction of the tunneling）的新方法；2）利用微腔内的模式耦合，提出了一种微变形度的光学微腔，使其能够在产生单向激光出射的同时，Q值远超过现有的制备的极限；3）研究了圆形微腔和变形微腔的耦合，通过这种光分子微腔得到了高Q值和单向激光出射的共存，同时利用这种高Q值和单向出射可以突破现有的高灵敏探测的极限，达到1个纳米左右的探测精度。4）利用光分子耦合腔，首次阐明了光分子中模式耦合带来的inverse Vernier effect，为光分子激光的研究提供了新的理论基础。5）研究了多边形单晶微腔内的激光模式，提出了一种利用模场耦合降低多边形微腔内准可积泄漏的新机制，同时得到了单纵模的激射。6）针对现有的半导体材料制备上的困难，我们进一步研究了新型的发光材料以及其对应的激光性质。.在本项目的支持下共发表学术论文30余篇，其中包括Advanced Optical Materials一篇，ACS Photonics一篇， Scientific Reports五篇，Physical Review A 三篇，Optics Letters两篇，Optics Express 3篇， Carbon一篇，Nanoscale一篇， Optics Material Express两篇，以及Plasmonic一篇。