Ahmed Safayet, Gan Yiyu, Saleque Ahmed Mortuza, Wu Honglei, Qiao Junpeng, Ivan Md Nahian Al Subri, Hani Sumaiya Umme, Alam Tawsif Ibne, Wen Qiao, Tsang Yuen Hong
Department of Applied Physics, Materials Research Center, Photonics Research Institute, and Research Institute for Advanced Manufacturing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China.
Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen, 518057, China.
Small Methods. 2024 Feb;8(2):e2300239. doi: 10.1002/smtd.202300239. Epub 2023 Jun 25.
2D semi-metallic hafnium ditelluride material is used in several applications such as solar steam generation, gas sensing, and catalysis owing to its strong near-infrared absorbance, high sensitivity, and distinctive electronic structure. The zero-bandgap characteristics, along with the thermal and dynamic stability of 2D-HfTe make it a desirable choice for developing long-wavelength-range photonics devices. Herein, the HfTe -nanosheets are prepared using the liquid-phase exfoliation method, and their superior nonlinear optical properties are demonstrated by the obtained modulation depth of 11.9% (800 nm) and 6.35% (1560 nm), respectively. In addition, the observed transition from saturable to reverse saturable absorption indicates adaptability of the prepared material in nonlinear optics. By utilizing a side polished fiber-based HfTe -saturable absorber (SA) inside an Er-doped fiber laser cavity, a mode-locked laser with 724 fs pulse width and 56.63 dB signal-to-noise ratio (SNR) is realized for the first time. The generated laser with this SA has the second lowest mode-locking pump threshold (18.35 mW), among the other 2D material based-SAs, thus paving the way for future laser development with improved efficiency and reduced thermal impact. Finally, employing this HfTe -SA, a highly stable single-frequency fiber laser (SNR ≈ 74.56 dB; linewidth ≈ 1.268 kHz) is generated for the first time, indicating its promising ultranarrow photonic application.
二维半金属碲化铪材料因其强近红外吸收、高灵敏度和独特的电子结构，被用于太阳能蒸汽产生、气体传感和催化等多种应用中。二维碲化铪的零带隙特性以及热稳定性和动态稳定性，使其成为开发长波长范围光子器件的理想选择。在此，采用液相剥离法制备了碲化铪纳米片，并通过分别获得11.9%（800纳米）和6.35%（1560纳米）的调制深度，证明了其优异的非线性光学特性。此外，观察到的从饱和吸收到反饱和吸收的转变表明所制备材料在非线性光学中的适应性。通过在掺铒光纤激光腔内使用基于侧面抛光光纤的碲化铪饱和吸收体（SA），首次实现了脉宽为724飞秒、信噪比（SNR）为56.63分贝的锁模激光器。与其他基于二维材料的饱和吸收体相比，用这种饱和吸收体制备的激光器具有第二低的锁模泵浦阈值（18.35毫瓦），从而为未来提高效率和降低热影响的激光发展铺平了道路。最后，首次使用这种碲化铪饱和吸收体产生了高度稳定的单频光纤激光器（信噪比≈74.56分贝；线宽≈1.268千赫），表明其在超窄光子应用方面具有广阔前景。
