We present an effective approach to realize a highly efficient, high-power and chirped pulse amplification-free ultrafast ytterbium-doped yttrium aluminum garnet thin-disk regenerative amplifier pumped by a zero-phonon line 969 nm laser diode. The amplifier delivers an output power exceeding 154 W at a pulse repetition rate of 1 MHz with custom-designed 48 pump passes. The exceptional thermal management on the thin disk through high-quality bonding, efficient heat dissipation and a fully locked spectrum collectively contributes to achieving a remarkable optical-to-optical efficiency of 61% and a near-diffraction-limit beam quality with an M² factor of 1.06. To the best of our knowledge, this represents the highest conversion efficiency reported in ultrafast thin-disk regenerative amplifiers. Furthermore, the amplifier operates at room temperature and exhibits exceptional stability, with root mean square stability of less than 0.33%. This study significantly represents advances in the field of laser amplification systems, particularly in terms of efficiency and average power. This advantageous combination of high efficiency and diffraction limitation positions the thin-disk regenerative amplifier as a promising solution for a wide range of scientific and industrial applications.

高功率激光器在工业应用领域的需求不断增长，提高光-光转化效率是降低其生产制造成本的关键途径。针对提高激光器光-光转化效率所面临的增益介质的热负荷问题，利用锁定波长的969 nm“零声子线”泵浦、自主研制的高性能Yb∶YAG薄片晶体和48冲程泵浦系统等，搭建了高效的连续Yb∶YAG薄片激光器系统，实现了最高输出功率373 W，光-光转化效率可达73.37%。其优异性能为后续开展千瓦级超快Yb∶YAG薄片激光器研究奠定了基础。

采用多级串联的主振荡放大技术，将SESAM锁模的种子光通过多级串联端泵Nd∶YVO₄晶体放大，产生平均功率为148.7 W、重复频率500 kHz~4 MHz、脉冲宽度8 ps的1 064 nm基频光，同时开展了LBO晶体高效率二倍频的研究。通过优化相位匹配，实现了平均功率为95 W的532 nm皮秒激光输出，光-光转换效率达65%，光束质量因子M_X²=1.27/M_Y²=1.42，6 h功率抖动均方根低于0.8%。该绿光皮秒激光系统具有平均功率高、转换效率高、光束质量好、稳定性高、重频可调等优点，可以被作为皮秒激光加工系统的光源，被应用于科学研究和工业加工领域。

A stable noise-like (NL) mode-locked Tm-doped fiber laser (TDFL) relying on a nonlinear optical loop mirror (NOLM) was experimentally presented. Different from the previous NL mode-locked TDFL with NOLM, the entire polarization-maintaining (PM) fiber construction was utilized in our laser cavity, which makes the oscillator have a better resistance to environmental perturbations. The robust TDFL can deliver stable bound-state NL pulses with a pulse envelope tunable from ～14.1 ns to ～23.6 ns and maximum pulse energy of ～40.3 nJ at a repetition rate of ～980.6 kHz. Meanwhile, the all-PM fiber laser shows good power stability (less than ～0.7%) and repeatability.

We experimentally demonstrated a type of tunable and switchable harmonic h-shaped pulse generation in a thulium-doped fiber (TDF) laser passively mode locked by using an ultralong nonlinear optical loop mirror. The total cavity length was ～3.03 km, the longest ever built for a TDF laser to our best knowledge, which resulted in an ultralarge anomalous dispersion over 200 ps2 around the emission wavelength. The produced h-shaped pulse can operate either in a fundamental or in a high-order harmonic mode-locking (HML) state depending on pump power and intra-cavity polarization state (PS). The pulse duration, no matter of the operation state, was tunable with pump power. However, pulse breaking and self-organizing occurred, resulting in high-order HML, when the pump power increased above a threshold. At a fixed pump power, the order of HML was switchable from one to another by manipulating the PS. Switching from the 8th up to the 48th order of HML was achieved with a fixed pump power of ～4.15 W. Our results revealed the detailed evolution and switching characteristics of the HML and individual pulse envelope with respect to both the pump power and PS. We have also discussed in detail the mechanisms of both the h-shaped pulse generation and the switching of its HML. This contribution would be helpful for further in-depth study on the underlying dynamics of long-duration particular-envelope pulses with ultralarge anomalous dispersion and ultralong roundtrip time.

Supercontinuum generation (SC) of more than one octave spectrum spanning covering from 400 nm to 820 nm was achieved by pumping a piece of aluminum nitride (AIN) single crystal using a nanosecond 355 nm ultraviolet laser. The AlN with a thickness of ～0.8 mm was grown by an optimized physical vapor transport technique and polished with solidification technology. Compared to previously reported ones, the achieved visible SC exhibited the broadest spectrum spanning from bulk materials pumped by a nanosecond pulse laser. The visible supercontinuum in AlN presents new opportunities for bulk material-based white light SC and may find more potential applications beyond typical applications in integrated semiconductive photoelectronic devices.

We demonstrate an integrated all-fiber mid-infrared (mid-IR) supercontinuum (SC) source generated by a 1.95 μm master oscillator power amplifier system and a single-mode ZBLAN (ZrF4–BaF2–LaF3–AlF3–NaF) fiber. The maximum average output power is 10.67 W with spectral bandwidth covering from ～1.9 to 4.1 μm. The single-mode ZBLAN fiber and silica fiber are thermal-spliced to enhance the robustness and practicability of the system. It is, to the best of our knowledge, the first high-power integrated compacted all-fiber mid-IR SC source based on thermal-spliced silica fiber and ZBLAN fiber.Postdoctoral Science Foundation (2015M572353, 2015M582407); Natural Science Foundation of SZU (201457); National Natural Science Foundation of China (NSFC)(61275144, 61308049); Science and Technology Projects of Shenzhen City (JCYJ20130329103213543, JCYJ20140418091413568, JCYJ20150324140036862).