Terahertz lasing without inversion based on quantum coherence between intersubband transitions: Pumping and lasing

基于子带间跃迁之间的量子相干性的无反转太赫兹激光：泵浦和激光

• 批准号: 157945847
• 负责人: Professor Dr. William Ted Masselink
• 金额: --
• 依托单位: Institut für Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/157945847?language=en
• 关键词: Terahertz; lasing; without; inversion; based

The common goal of the groups at the Humboldt-Universität zu Berlin (HUB) and the Paul-Drude- Institut (PDI) is the demonstration of lasing based on gain due to quantum coherence as well as the comprehensive understanding of underlying physical processes. The proposed system consists of a high-power mid-infrared quantum-cascade laser (MIR QCL) for pumping and an optically pumped, electrically driven terahertz quantum laser (TQL). The objectives of the HUB group to realize the common goal are the optimization of the MIR pump QCLs in terms of power, beam quality, and tunability within an external-cavity, the optimization of the coupling between the MIR QCL and the TQL structure using two new approaches, and, together with the PDI, the demonstration and investigation of a functional TQL. To achieve these objectives and the common goal, the active region of the MIR QCL must be optimized for injection efficiency, requiring a deeper understanding of the mechanisms that scatter electrons into higher-lying energy states. This understanding will allow for an increase of the emission power to the required 30 W. At the same time, the QCL active region also needs to be optimized for sufficient external-cavity tuning, maintaining a large transition efficiency. In addition, two approaches will be pursued to optimize the coupling of the MIR emission into the TQL structure: butt coupling of an external cavity QCL and lateral coupling using higher-order gratings on both the MIR QCL and the TQL structures. Finally, the response of the TQL structure to the incoupled MIR radiation will be investigated in the third objective in order to demonstrate the functionality of the TQL. In particular, THz emission as a function of MIR power, bias, coupling, and temperature will be measured. This proposal is specifically focused on developing the MIR QCLs for the optical pumping part of this system and coupling the 10-pm excitation beam into the TQL structure. This GaAs/(AI,Ga)Asbased cascade structure that defines the THz emission transitions will be developed and investigated within the parallel project submitted by the PDI group. The project goal, the demonstration of a complete THz laser based on quantum coherence, will be developed in collaboration with the PDI group.

柏林洪堡大学(HUB)和保罗-德鲁德研究所(PDI)的研究小组的共同目标是展示基于量子相干增益的激光以及对潜在物理过程的全面理解。该系统由用于泵浦的高功率中红外量子级联激光器(MIR QCL)和光泵浦、电驱动的太赫兹量子激光器(TQL)组成。中心小组实现共同目标的目标是在功率、光束质量和外腔内可调谐方面优化MIR泵浦QCL，使用两种新方法优化MIR QCL和TQL结构之间的耦合，以及与PDI一起演示和研究功能TQL。为了实现这些目标和共同目标，必须优化MIR QCL的有源区以提高注入效率，这需要对散射电子进入更高能态的机制有更深入的了解。这一理解将允许将发射功率增加到所需的30W。同时，QCL有源区也需要优化以实现足够的外腔调谐，从而保持较高的转换效率。此外，还将寻求两种方法来优化MIR发射到TQL结构中的耦合：外腔QCL的对接耦合和在MIR QCL和TQL结构上使用高阶光栅的横向耦合。最后，将在第三个目标中研究TQL结构对相互耦合的MIR辐射的响应，以演示TQL的功能。特别是，将测量作为MIR功率、偏置、耦合和温度的函数的太赫兹辐射。该方案的重点是研制用于该系统光抽运部分的MIR QCL，并将10 PM激发光耦合到TQL结构中。这种基于GaAs/(Al，Ga)As的级联结构定义了THz发射跃迁，将在PDI小组提交的平行项目中进行开发和研究。该项目的目标是演示一个完整的基于量子相干的太赫兹激光器，将与PDI小组合作开发。