Ultra-precision optical engineering with short-wavelength semiconductor disk laser technology

激光的首次使用已经过去了50年，但由于激光技术的不断创新，仍有许多新的应用成为可能。科学家和工程师目前正在开发一系列令人兴奋的光学工程技术，以实现传感、制造和测量方面的更高精度：从制造由激光图案创建的纳米级晶体结构到探测原子能级以定义用于通信和导航的时间和频率标准。这种基于可见光和紫外线(短波长)的研究非常活跃；然而，研究人员目前正在凑合，不得不相当熟练地将当前的激光器与用于光束整形、放大和频率转换的复杂系统进行转换，这些系统通常达不到所需的波长、功率和精确度，并将这项技术限制在实验室中。该计划将与这些科学家和工程师合作，开发一种新的简化和定制的短波长激光系统，以解决激光工具箱中的一个空白，显著提高性能，并将这些目前的专门技术从实验室带到广泛应用的技术水平。目标光学工程系统的核心激光技术将是半导体光盘激光器(SDL)。SDL与传统的高性能激光器的不同之处在于，增益材料是在纳米尺度上设计的。光放大不是激光晶体(毫米长)、染料流或加压气体管，而是由几个量子井(QW)提供的：超薄(几纳米厚)的半导体层，相对于激光中的光场以纳米级的精度定位。除了在紧凑性、成本和波长灵活性方面的商业优势外，这种设置从根本上适合于超精密光学工程所需的非常高的相干性、低噪声的激光性能。几乎所有的SDL都工作在光谱的近红外或中红外区域；然而，如果它们的可见光和紫外光工作的全部潜力被实现，将会有更多的应用。Hastie博士的团队在过去5年中开发了短波长SDL的独特功能，这意味着她现在能够推动这项技术针对真正的应用，以获得更广泛的好处。她已经确定了英国和国际研究伙伴，与英国研究机构的最终用户一起，在可见光和紫外光中实现高精确度半导体激光系统。挑战工程奖将为领导这一研究网络和解决已确定的挑战提供必要的平台。最初将针对三种不同的光学工程系统：*干涉光刻--一种在半导体行业制造电路中广泛应用的有效、低成本的纳米结构方法*紫外线光谱学--用于测量重要大气痕量气体的浓度*光学时钟--用于改进用于通信、卫星导航和基础物理测试的时间和频率标准。就所需的激光工程和性能而言，这些领域是互补的，将通过应用短波长SDL实现能力的阶梯变化。并具有足够的多样性，为积极追求多种有前途的研究方向和应用提供了空间，其中许多尚未被预测。

It has been 50 years since the first operation of the laser, yet there are still many new applications being made possible by continued innovation in laser technology. A range of exciting optical engineering techniques are currently being developed by scientists and engineers to achieve ever greater precision in sensing, manufacturing, and measurement: from the fabrication of nanometre-scale crystal structures created by laser light patterns to the probing of atomic energy levels to define the time and frequency standards used for communications and navigation. Such visible- and ultraviolet-based (short wavelength) research is very active; however, investigators are currently making do and having to become rather adept at converting current lasers with complex systems for beam shaping, amplification and frequency conversion which generally fall short of the desired wavelength, power and finesse, and confine this technology to the lab. This programme will develop a new class of simplified and tailored short wavelength laser systems in collaboration with these scientists and engineers in order to address a gap in the laser toolbox, dramatically improve capability, and bring these currently specialist techniques out of the lab to the level of widely deployed technology.The core laser technology for the optical engineering systems targeted will be semiconductor disk lasers (SDLs). SDLs are distinct from conventional high performance lasers in that the gain material is engineered on the nanometre scale. Rather than a laser crystal (millimetres long), a flow of dye, or a pressurised tube of gas, light amplification is provided by several quantum wells (QWs): ultra-thin (few nanometres thick) layers of semiconductor, positioned with nanometre-scale accuracy with respect to the light field in the laser. Aside from commercial advantages in terms of compactness, cost and wavelength flexibility, this set-up is fundamentally suited to the very high coherence, low noise laser performance required for ultra-precision optical engineering.Nearly all SDLs operate in the near- or mid-infrared regions of the spectrum; however, many more applications will open up if their full potential for visible and ultraviolet operation is realised. The unique capability in short wavelength SDLs that Dr. Hastie's team has developed over the past 5 years means that she is now in a position to push the technology to target genuine applications for wider benefit. She has identified UK and international research partners for the realisation of high finesse semiconductor laser systems in the visible and UV, together with end users at research institutions in the UK. The Challenging Engineering award will provide the platform necessary to lead this research network and address the identified challenges.Three different optical engineering systems will be targeted initially:* interference lithography - an effective, low-cost method of fabricating nanostructures over a large area and widely deployed in the fabrication of circuits in the semiconductor industry* ultraviolet spectroscopy - for measuring the concentrations of important atmospheric trace gases* optical clocks - for the improvement in time and frequency standards used for communications, satellite navigation and testing of fundamental physics.These areas are complementary in terms of the required laser engineering and performance, will achieve a step-change in capability through the application of short wavelength SDLs, and are sufficiently diverse to provide scope to actively pursue multiple promising research directions and applications, many not yet predicted.