Astrocomb development for the ELT: enhancing capability with a modern laser platform

该提案旨在确保所需的资本资金，以支持赫瑞瓦特大学继续开发激光频率梳（LFC）技术，这是下一代新望远镜（如ELT）中光谱仪超精确校准所需的。具体而言，该设备将支持E-ELT PPRP资助ST/S 001328/1（“英国ELT计划”）和财团资助ST/V000403/1（“使用单模光子技术的精密天文光谱仪”）的研究。Heriot-Watt的LFC架构基于单个超快钛宝石激光器。该激光器产生持续时间约为30飞秒的“超快”激光脉冲，重复频率为1 GHz。这些脉冲用作波长下转换、可见光和近红外宽带超连续谱产生、法布里-珀罗梳状滤波和梳状计量/传输的许多光束线的泵浦源。近十年来，我们的天文梳的开发一直围绕着一个开放的盒子钛：蓝宝石激光器，具有有限的输出功率，现在需要耗时的维护和调整。由于这些原因，它现在不太适合日益复杂的下游系统，我们正在为英国ELT计划开发阶段B试点，并在其他更广泛的研究中探索新的，强大的天文梳配置。这个单一项目的设备投标是一个现代化的替代激光器，提供50%的更大的功率（允许光束在更多的光束线分裂）在一个密封的零维护单元。这款激光器不仅可以避免数周的累积维护，从而大幅提高我们的生产率，而且它与目前ELT-HIRES校准装置中采用的激光平台完全相同，后者需要密封、零维护和全自动化的激光源。我们的建议在以下方面符合评估标准：（A）STFC计划中的战略价值所要求的激光器将直接加强基本天文梳技术的研究和开发，必须在大约10年的时间内部署在ELT这样的望远镜上。英国（剑桥、达勒姆、UKATC、Heriot-Watt）在意大利领导的ELT-HIRES光谱仪开发中发挥着重要的战略作用，该光谱仪需要天文梳进行超精确的波长校准。这一设备请求将确保联合王国继续在ELT-HIRES光谱仪校准的硬件开发方面发挥重要作用。(B)及时性正如Laser Quantum（Novanta）的支持信所确认的那样，设备可以按照资助条件的要求在2022年3月31日之前投入使用。值得注意的是，ST/S 001328/1和ST/V 000403/1项目的使用寿命从这一日期起将为一至三年，因此这些设备将有可能加强和加速这些赠款所支持的研究方案。

This proposal aims to secure capital funding needed to support the continued development of laser frequency comb (LFC) technologies at Heriot-Watt University, which are needed for ultra-precise calibration of spectrographs in the next generation of new telescopes, such as the ELT. Specifically, the equipment will support research on E-ELT PPRP grant ST/S001328/1 ("The UK ELT Programme") and consortium grant ST/V000403/1 ("Precision Astronomical Spectrographs using Single-Mode Photonic Technologies"). Heriot-Watt's LFC architecture is based around a single ultrafast Ti:sapphire laser. This laser produces "ultrafast" laser pulses with durations of around 30 femtoseconds and with a repetition frequency of 1 GHz. These pulses serve as the pump source for a number of beamlines for wavelength down-conversion, visible- and near-infrared broadband supercontinuum generation, Fabry-Pérot étalon comb filtering and comb metrology / delivery. For nearly ten years, our astrocomb development has been based around an open-box Ti:sapphire laser, with limited output power, and now requiring time-consuming maintenance and realignment. For these reasons it is now poorly suited to the increasingly complex downstream systems that we are developing as a Phase B pilot for the UK ELT programme and in other wider research exploring new, robust astrocomb configurations.This single-item equipment bid is for a modern replacement laser offering 50% greater power (allowing the beam to be split across a greater number of beamlines) in a sealed zero-maintenance unit. Not only will this laser dramatically increase our productivity by avoiding many cumulative weeks of maintenance, but it is identical to the unit which is currently our laser platform of choice for adoption in the ELT-HIRES calibration unit, which requires a sealed, zero-maintenance and fully automatable laser source.Our proposal meets the assessment criteria in the following ways:(A) Strategic value within the STFC programmeThe requested laser will directly enhance research and development of basic astrocomb technologies, that must be deployed in around 10 years' time on telescopes such as the ELT. The UK (Cambridge, Durham, UKATC, Heriot-Watt) has a significant strategic role in the Italian-led ELT-HIRES spectrograph development, on which an astrocomb is needed for ultra-precise wavelength calibration. This equipment request will ensure that the UK continues to play an important role in the hardware development for the calibration of the ELT-HIRES spectrograph.(B) TimelinessAs the letter of support from Laser Quantum (Novanta) confirms, the equipment can be commissioned by 31 March 2022 as required in the conditions of the grant. Notably, projects ST/S001328/1 and ST/V000403/1 will have lifetimes of between one and three years from this date, and so the equipment will have the potential to enhance and accelerate the research programmes supported by these grants.