高功率单频连续波266 nm激光在大容量信息存储、高分辨光谱监测及高精度紫外光刻等领域具有重要应用价值，近年来已成为国内外紫外激光领域的研究热点之一。文中首先综合比较了用于产生高功率266 nm紫外激光的非线性光学晶体基本性能，并根据主要的激光器频率锁定方法，重点分析了Hänsch-Couillaud (H-C)频率锁定和Pound-Drever-Hall (PDH)频率锁定方法的优缺点以及连续波单频266 nm激光器发展现状，介绍了本课题组最新研究成果，即基于H-C频率锁定方法实现了功率1.1 W的单频连续波266 nm紫外激光稳定输出。最后，针对进一步提升全固态单频连续波266 nm激光器性能亟需解决的问题和可能解决路径进行了简要分析和展望。

We firstly report a 2-μm all-fiber nonlinear pulse compressor based on two pieces of normal dispersion fiber (NDF), which enables a high-power scaling ability of watt-level and a high pulse compression ratio of 13.7. With the NDF-based all-fiber nonlinear pulse compressor, the 450-fs laser pulses with a repetition rate of 101.4 MHz are compressed to 35.1 fs, corresponding to a 5.2 optical oscillation cycle at the 2-μm wavelength region. The output average power reaches 1.28 W, which is believed to be the highest value never achieved from the previous 2-μm all-fiber nonlinear pulse compressors with a high pulse repetition rate above 100 MHz. The dynamic evolution of the ultrafast pulse inside the all-fiber nonlinear pulse compressor is numerically analyzed, matching well with the experimental results.

In this paper, a high-power and high-efficiency 4.3µm mid-infrared (MIR) optical parametric oscillator (OPO) based on ZnGeP2 (ZGP) crystal is demonstrated. An acousto-optically Q-switched Ho:Y3Al5O12 laser operating at 2.1µm with a maximum average output power of 35 W and pulse width of 38 ns at a repetition rate of 15 kHz is established and employed as the pump source. A doubly resonant OPO is designed and realized with the total MIR output power of 13.27 W, including the signal and idler output power of 2.65 W at 4.07µm and 10.62 W at 4.3µm. The corresponding total optical-to-optical and slope efficiencies are 37.9% and 67.1%, respectively. The shortest pulse width, beam quality factor, and output power instability are measured to be 36 ns, Mx2=1.8, My2=2.0, and RMS<1.9% at 8 h, respectively. Our results pave a way for designing high-power and high-efficiency 4–5µm MIR laser sources.

稀土离子Tm³⁺/ Ho³⁺ 掺杂中红外2 μm波段超快激光由于广泛的应用前景成为近十余年来激光领域的研究热点之一。文中首先综述了稀土离子Tm³⁺/Ho³⁺掺杂固体/光纤2 μm波段超快激光锁模技术进展，包括主动锁模技术以及饱和吸收、克尔透镜、非线性偏振旋转、非线性光环形镜、非线性多模干涉等被动锁模技术；其次，结合激光增益介质及色散管理技术回顾了Tm³⁺/ Ho³⁺掺杂固体和光纤锁模激光脉冲宽度压缩进展；再次，总结了Tm³⁺/ Ho³⁺大能量/高功率超快激光技术及进展；最后，对2 μm波段超快激光发展趋势进行了总结和展望。

Mid-infrared (MIR) laser sources operating in the 2.7–3 µm spectral region have attracted extensive attention for many applications due to the unique features of locating at the atmospheric transparency window, corresponding to the “characteristic fingerprint” spectra of several gas molecules, and strong absorption of water. Over the past two decades, significant developments have been achieved in 2.7–3 µm MIR lasers benefiting from the sustainable innovations in laser technology and the great progress in material science. Here, we mainly summarize and review the recent progress of MIR bulk laser sources based on the rare-earth ions-doped crystals in the 2.7–3 µm spectral region, including Er3+-, Ho3+-, and Dy3+-doped crystalline lasers. The outlooks and challenges for future development of rare-earth-doped MIR bulk lasers are also discussed.

Indium arsenide phosphide (InAsP) nanowires (NWs), a member of the III–V semiconductor family, have been used in various photonic and optoelectronic applications thanks to their unique electrical and optical properties such as high carrier mobility and adjustable band gap. In this work, we synthesize InAsP NWs and further explore their nonlinear optical properties. The ultrafast carrier dynamics and nonlinear optical response are thoroughly studied based on the nondegenerate pump probe and Z-scan experimental measurements. Two different characteristic carrier lifetimes (∼2 and ∼15ps) from InAsP NWs are observed during the excited-carrier relaxation process. Based on the physical model analysis, the relaxation process can be ascribed to the carrier cooling process via carrier-phonon scattering and Auger recombination. In addition, based on the measured excited-carrier lifetime and Pauli-blocking principle, we discover that InAsP NWs show strong saturable absorption properties at the wavelengths of 532 and 1064 nm. Last, we demonstrate for the first time a femtosecond (∼426fs) solid-state laser based on an InAsP NWs saturable absorber at 1.04 μm. We believe that our work provides a better understanding of the InAsP NWs optical properties and will further advance their photonic applications in the near-infrared range.

In this paper, the absorption and fluorescence spectra of Er3+, Pr3+ co-doped LiYF4 (Er,Pr:YLF) crystal were measured and analyzed. The Pr3+ co-doping was proved to effectively enhance the Er3+:I411/2→I413/2 mid-infrared transition at the 2.7 μm with 74.1% energy transfer efficiency from Er3+:I413/2 to Pr3+:F34. By using the Judd–Ofelt theory, the stimulated emission cross section was calculated to be 1.834×10-20cm2 at 2685 nm and 1.359×10-20cm2 at 2804.6 nm. Moreover, a diode-end-pumped Er,Pr:YLF laser operating at 2659 nm was realized for the first time, to the best of our knowledge. The maximum output power was determined to be 258 mW with a slope efficiency of 7.4%, and the corresponding beam quality factors Mx2=1.29 and My2=1.25. Our results suggest that Er,Pr:YLF should be a promising material for 2.7 μm laser generation.