A coherent, compact and robust light source with coverage from the ultraviolet to the infrared is desirable for heterodyne super-resolution imaging¹, broadband infrared microscopy², protein structure determination³ and standoff trace-gas detection⁴. To address these demanding problems, frequency combs⁵ combine absolute frequency accuracy with sub-femtosecond timing and waveform control to enable high-resolution, high-speed and broadband spectroscopy^6,7,8,9. Here we demonstrate a scalable source of near-single-cycle pulses from robust and low-noise erbium fibre (Er:fibre) technology. With a peak power of 0.56 MW we generate a comb spanning six octaves, from the ultraviolet (350 nm) to the mid-infrared (22,500 nm), achieving a resolving power of 10¹⁰ across 0.86 PHz of bandwidth. Second-order nonlinearities in LiNbO₃, GaSe and CdSiP₂ provide phase-stable infrared ultrashort pulses with simultaneous brightness exceeding a synchrotron¹⁰, while cascaded nonlinearities in LiNbO₃ yield four octaves simultaneously (0.350–5.6 μm). We anticipate that these advances will be enabling for basic and applied spectroscopy, microscopy and phase-sensitive nonlinear optics.

外差超分辨率成像¹、宽带红外显微镜²、蛋白质结构测定³和隔离痕量气体检测⁴需要一个连贯、紧凑且坚固的光源，其覆盖范围从紫外到红外。为了解决这些苛刻的问题，频率梳⁵将绝对频率精度与亚飞秒定时和波形控制相结合，以实现高分辨率、高速和宽带光谱^6,7,8,9. 在这里，我们展示了来自稳健和低噪声铒光纤（Er：光纤）技术的近单周期脉冲的可扩展源。凭借 0.56 MW 的峰值功率，我们生成了一个跨越六个倍频程的梳状信号，从紫外（350 nm）到中红外（22,500 nm），在 0.86 PHz 的带宽上实现了 10 ^{10的分辨能力。}_{LiNbO 3}、GaSe 和 CdSiP ₂中的二阶非线性提供相位稳定的红外超短脉冲，同时亮度超过同步加速器¹⁰，而 LiNbO ₃中的级联非线性同时产生四个倍频程（0.350-5.6 μm）。我们预计，这些进展将使基本和应用光谱学、显微镜和相敏非线性光学器件成为可能。