Zaugg C A, Sun Z, Wittwer V J, Popa D, Milana S, Kulmala T S, Sundaram R S, Mangold M, Sieber O D, Golling M, Lee Y, Ahn J H, Ferrari A C, Keller U
Opt Express. 2013 Dec 16;21(25):31548-59. doi: 10.1364/OE.21.031548.
We report a versatile way of controlling the unsaturated loss, modulation depth and saturation fluence of graphene-based saturable absorbers (GSAs), by changing the thickness of a spacer between a single layer graphene (SLG) and a high-reflection mirror. This allows us to modulate the electric field intensity enhancement at the GSA from 0 up to 400%, due to the interference of incident and reflected light at the mirror. The unsaturated loss of the SLG-mirror-assembly can be reduced to ∼0. We use this to mode-lock a vertical-external-cavity surface-emitting laser (VECSEL) from 935 to 981 nm. This approach can be applied to integrate SLG into various optical components, such as output coupler mirrors, dispersive mirrors or dielectric coatings on gain materials. Conversely, it can also be used to increase the absorption (up to 10%) in various graphene based photonics and optoelectronics devices, such as photodetectors.
我们报道了一种通用方法，通过改变单层石墨烯（SLG）与高反射镜之间间隔层的厚度，来控制基于石墨烯的可饱和吸收体（GSA）的不饱和损耗、调制深度和饱和通量。由于光在镜面上的入射和反射干涉，这使我们能够将GSA处的电场强度增强从0调制到400%。SLG - 镜组件的不饱和损耗可降低至约0。我们利用此方法将垂直外腔面发射激光器（VECSEL）在935至981 nm范围内实现锁模。该方法可应用于将SLG集成到各种光学元件中，如输出耦合镜、色散镜或增益材料上的介质涂层。相反，它也可用于提高各种基于石墨烯的光子学和光电器件（如光电探测器）中的吸收率（高达10%）。
