MacV - VCSELs for miniature atomic clocks

基于相干布居俘获(CPT)的微型原子钟需要低功率的单模激光二极管，可以在几吉赫兹直接调制。垂直腔面发射激光器(VCSEL)是这种应用的理想选择，主要是因为它们的功耗非常低、波长调谐系数较宽、对光反馈的敏感度降低、延长了器件寿命以及器件占地面积小。商用VCSEL的线宽约为50-100 MHz，虽然这对许多其他激光光谱应用来说可能是一个问题，但它不会实质上影响CPT共振的质量。相反，由于圆形光束轮廓，VCSEL特别容易受到偏振不稳定性的影响；然而，有几种新的设计改进可以解决这个问题。目前，英国还没有可靠和坚固的微型原子钟VCSEL的来源或任何供应链，全球只有非常有限的商业制造商为应用(Csd1-894 nm)开发鸦片波长的VCSEL。我们的项目将建立英国的战略能力，专注于VCSEL激光光源的开发和批量生产，专门为支持微型原子钟应用而量身定做。

Coherent population trapping (CPT) based miniature atomic clocks require low power, single mode laser diodes that can be directly modulated at a few gigahertz. Vertical Cavity Surface Emitting Lasers (VCSELs) are ideal for this application primarily due to their very low power consumption, wide wavelength tuning coefficient, reduced sensitivity to optical feedback, extended device lifetime, and small device footprint. Commercially available VCSELs have linewidths of ~50-100 MHz, and while this can be a problem for many other laser spectroscopy applications, it does not substantially compromise the quality of a CPT resonance. Conversely, due to the circular beam profile, VCSELs are particularly susceptible to polarisation instabilities; however, there are several novel design modifications that can be implemented to address this issue. Currently, there are no UK sources or any supply chain of reliable and robust VCSELs for miniature atomic clocks and a very limited number of commercial manufacturers globally developing VCSELs at the opimium wavelength for the application (CsD1 – 894nm). Our project will establish a UK strategic capability focussed on the development and volume production of VCSEL laser sources, tailored specifically to support the adoption of miniaturised atomic clock applications.