Spent coffee ground (SCG) was demonstrated as saturable absorber (SA) for Wideband Q-switched fiber lasers generation. The SCG SA has a broad linear absorption that covers from 1000 nm to 2000 nm wavelength and a modulation depth of 30% at 1.55-µm region. Through purification process, the finer SCG powder is obtained, and be embedded with a polyvinyl alcohol for thin film formation. To realize Q-switching operation lasers, a fabricated SCG film was integrated into three different fiber laser cavities including ytterbium-doped fiber laser, erbium-doped fiber laser, and thulium-doped fiber laser. A peak wavelength has obtainable at 1031 nm, 1563 nm, and 1976 nm for 1-, 1.55-, and 2- µm regions, respectively. The shortest pulse width of 4.80 µs and maximum pulse energy of 0.152 µJ are observed from the YDFL cavity. RF spectrum shows the signal-to-noise ratio for all regions is above 35 dB, indicates a stable pulsing generation. Our technique opens the door for unlimited materials SA from environmentally friendly resources which contribute to sustainable effort.

已证明用过的咖啡渣（SCG）可作为宽带Q开关光纤激光器产生的可饱和吸收剂（SA）。SCG SA具有宽的线性吸收范围，可吸收1000 nm至2000 nm的波长，在1.55 µm的区域内的调制深度为30％。通过纯化过程，可以获得更细的SCG粉末，并将其嵌入聚乙烯醇中以形成薄膜。为了实现Q开关操作激光器，将制成的SCG膜集成到三个不同的光纤激光器腔中，这些光纤激光器腔包括掺光纤激光器，掺fiber光纤激光器和掺th光纤激光器。在1、1.55和2 µm区域分别具有1031 nm，1563 nm和1976 nm的峰值波长。从YDFL腔中观察到最短的脉冲宽度为4.80 µs，最大脉冲能量为0.152 µJ。射频频谱显示所有区域的信噪比均高于35 dB，表明产生了稳定的脉冲。我们的技术为利用可持续发展的环保资源为无限材料SA开辟了大门。