SUPA, School of Physics and Astronomy, University of St Andrews, Scotland KY16 9SS, UK.
M Squared Lasers Ltd, Venture Building, 1 Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP, UK.
Nat Commun. 2017 Jun 5;8:15610. doi: 10.1038/ncomms15610.
The accurate determination and control of the wavelength of light is fundamental to many fields of science. Speckle patterns resulting from the interference of multiple reflections in disordered media are well-known to scramble the information content of light by complex but linear processes. However, these patterns are, in fact, exceptionally rich in information about the illuminating source. We use a fibre-coupled integrating sphere to generate wavelength-dependent speckle patterns, in combination with algorithms based on the transmission matrix method and principal component analysis, to realize a broadband and sensitive wavemeter. We demonstrate sub-femtometre wavelength resolution at a centre wavelength of 780 nm, and a broad calibrated measurement range from 488 to 1,064 nm. This compares favourably to the performance of conventional wavemeters. Using this speckle wavemeter as part of a feedback loop, we stabilize a 780 nm diode laser to achieve a linewidth better than 1 MHz.
准确确定和控制光的波长是许多科学领域的基础。在无序介质中多次反射的干涉产生的散斑模式通过复杂但线性的过程很好地扰乱了光的信息内容。然而，这些模式实际上包含了关于照明源的异常丰富的信息。我们使用光纤耦合积分球来产生波长相关的散斑图案，结合基于传输矩阵方法和主成分分析的算法，实现了一种宽带和高灵敏度的波谱仪。我们在中心波长为 780nm 时实现了亚飞米波长分辨率，并在 488nm 至 1064nm 的宽校准测量范围内实现了测量。这与传统波谱仪的性能相比具有优势。我们使用这种散斑波谱仪作为反馈环的一部分，将 780nm 二极管激光器稳定到线宽优于 1MHz。
