Diffraction-grating coupled surface emitting Terahertz quantum cascade laser source for high power, room temperature continuous wave operation

用于高功率、室温连续波操作的衍射光栅耦合表面发射太赫兹量子级联激光源

• 批准号: 1607838
• 负责人: Manijeh Razeghi
• 金额: $ 40万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-15 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607838&HistoricalAwards=false
• 关键词: Diffraction; grating; coupled; surface; emitting

Abstract TitleChip-based, High-Power Surface Emitting Terahertz SourceAbstractNon-technical:The terahertz (THz) radiation in the frequency range of ~1-5 THz has mainly unique properties and applications in imaging, sensing, spectroscopy, communication, and medical diagnosis. Most of these applications requires a sufficient THz light power density so that the light can pass through materials and able to be detected for analysis. This has fueled intense studies on the generation of high power THz light in the past decades. The recent demonstrated THz source based on nonlinear generation inside a mid-IR quantum cascade laser (QCL) is proved to be the only room temperature semiconductor light source that delivers mW-level power at room temperature in the 1-5 THz range. The main challenge for this type of sources is to generate higher THz power up to tens of milliwatts with good beam quality which is required by most of the real-world application. A novel approach is proposed to develop a chip-based THz source with high power output by extracting THz light from the entire cavity. This simple to use and compact source will be an enabling technology which will allow easy access to THz spectroscopy/ imaging for the broader scientific community.Technical:The objective of the proposed research is to demonstrate a room temperature, monolithic THz source with sub-milliwatt level output power in continuous wave operation and tens of milliwatt level in pulsed mode operation. In the previous demonstrations, edge-emitting THz sources based on nonlinear generation inside a mid-IR QCL have limited outcoupling efficiency (~6-10%) due to the limited outcoupling aperture size regarding to the entire cavity. The approach in this proposed project is to use a surface-emission scheme based on THz diffraction grating defined in the semi-insulating InP substrate of a epi-down bonded THz QCL source for high-power and efficient THz outcoupling. Unlike the traditional distributed-feedback (DFB) grating which interacts with the guiding laser modes by providing the optical feedback, the proposed THz diffraction grating simply diffract the incident Cerenkov emission cone into the discrete directions. With an optimized grating structure, surface emission from the entire cavity with diffraction efficiency up to 90% is achievable. This will drastically increase the THz outcoupling efficiency and power. In contrast to a THz sources based gas lasers, which is bulky and expensive, the proposed THz QCL source offers a monolithic solution that, once developed, has potential for cost-effective mass production using the existing semiconductor laser fabrication infrastructure. This project is an excellent example of a multidisciplinary approach used to circumvent existing technological limitations. Solid state physics, material science, nonlinear optics, and laser physics are all major components of the research plan, which are all supported generally by NSF, and are used, in this case, together to combine multiple functional elements into a single, compact, high power device.

基于抽象的滴定，高功率表面发射Terahertz Sourceabstractnon-Technical：〜1-5 THz的频率范围内的Terahertz（THZ）辐射主要具有成像，传感，光谱，传播，通讯和医学诊断的独特属性和应用。这些应用中的大多数都需要足够的THZ光功率密度，以便光线可以通过材料并可以检测到进行分析。在过去的几十年中，这引发了人们对高功率THZ光产生的强烈研究。最近，基于MID-IR量子级联激光器（QCL）内的非线性生成的THZ来源被证明是唯一在1-5 THZ范围内在室温下提供MW级功率的室温半导体光源。这种类型的来源的主要挑战是，具有良好的光束质量的较高的THZ功率，这是大多数现实世界应用所需的。提出了一种新型方法，以通过从整个腔中提取THZ光来开发具有高功率输出的基于芯片的THZ源。这种易于使用和紧凑的来源将是一项有能力的技术，可以轻松访问更广泛的科学界的光谱/成像。技术：拟议的研究的目的是证明室温，单层THZ源具有持续级别波动和脉冲模式下的毫米级波动中的子毫微米级输出功率。在先前的示范中，由于对整个腔内的超过耦合孔径大小有限，因此基于MID-IR QCL内部非线性生成的边缘发射THZ源超过耦合效率（〜6-10％）。该提出的项目中的方法是使用基于EPI降低键合的THZ QCL源的半胰岛INP INP底物定义的表面发射方案，以进行高功率和有效的THZ超越耦合。与传统的分布式反馈（DFB）光栅不同，它通过提供光学反馈与引导激光模式相互作用不同，提出的THZ衍射光栅只需衍射衍射的Cerenkov发射锥到离散方向。通过优化的光栅结构，可以实现从整个腔体发出衍射效率高达90％的表面发射。这将大大提高THZ的超耦合效率和功率。与笨重且昂贵的基于THZ源的气体激光器相反，拟议的THZ QCL源提供了一种单片解决方案，该解决方案曾经开发，它具有使用现有的半导体激光制造基础设施的具有成本效益的质量生产的潜力。该项目是用于规避现有技术限制的多学科方法的一个很好的例子。固态物理学，材料科学，非线性光学和激光物理都是研究计划的主要组成部分，这些组成部分通常由NSF支持，在这种情况下，将多个功能元素合并为单个紧凑的高功率设备。