A supercontinuum white laser with ultrabroad bandwidth, intense pulse energy, and high spectral flatness can be accomplished via synergic action of third-order nonlinearity (3rd-NL) and second-order nonlinearity. In this work, we employ an intense Ti:sapphire femtosecond laser with a pulse duration of 50 fs and pulse energy up to 4 mJ to ignite the supercontinuum white laser. Remarkably, we use water instead of the usual solid materials as the 3rd-NL medium exhibiting both strong self-phase modulation and stimulated Raman scattering effect to create a supercontinuum laser with significantly broadened bandwidth and avoid laser damage and destruction. Then the supercontinuum laser is injected into a water-embedded chirped periodically poled lithium niobate crystal that enables broadband and high-efficiency second-harmonic generation. The output white laser has a 10 dB bandwidth encompassing 413 to 907 nm, more than one octave, and a pulse energy of 0.6 mJ. This methodology would open up an efficient route to creating a long-lived, high-stability, and inexpensive white laser with intense pulse energy, high spectral flatness, and ultrabroad bandwidth for application to various areas of basic science and high technology.

We report the modulation of epsilon-near-zero (ENZ) wavelength and enhanced third-order nonlinearity in indium tin oxide (ITO)/Au multilayer films. The samples consisting of five-layer 40 nm ITO films spaced by four-layer ultrathin Au films of different thickness, i.e., ITO(40 nm)/[Au(x)/ITO(40 nm)]₄, were prepared by magnetron sputtering at room temperature. The ENZ wavelength in the multilayer films is theoretically calculated and experimentally confirmed. The nonlinear refractive index and nonlinear absorption coefficient of the samples of x=0, 2, 3, 4 nm were determined using the Z-scan method at a wavelength of 1.064 µm. The large nonlinear refractive index n₂=1.12×10-13m2/W and nonlinear absorption coefficient β=-1.78×10-7m/W in the sample of x = 4 nm are both four times larger than those in the single-layer ITO film. The large optical nonlinearity due to the ENZ enhancement and carrier concentration is discussed. The results indicate that the ITO/Au multilayer films are promising for advanced all-optical devices.

硫化物玻璃是发展非线性集成光学器件的良好材料，特殊的理化特性使得硫化物玻璃集成光学波导的制备成为研究的难点。对硫化物玻璃波导的制备工艺进行了综述，重点介绍利用硫化物玻璃在熔融状态下流动性好的特点，采用热熔融自回流方法制备硫化物玻璃波导的工艺。该方法避免了对硫化物玻璃薄膜完整性的破坏，以及光刻胶显影液对硫化物玻璃材料的腐蚀作用，可以得到高质量的具有小模场面积的倒脊型硫化物玻璃波导。实验测试表明，采用热熔融自回流方法制备的硫化物玻璃波导具有良好的三阶非线性光学特性和受激布里渊散射特性。最后，展望了采用该方法发展硫化物玻璃非线性集成光学器件及其片上系统的研究方向和前景。

The input pulse of the laser PEARL with energy of 18 J and pulse duration of about 60 fs was compressed to 10 fs after passage through a 4-mm-thick KDP crystal and reflection at two chirped mirrors with sum dispersion of -200 fs². The experiments were performed for the В-integral values from 5 to 19 without visible damage to the optical elements, which indicates that small-scale self-focusing is not a significant issue. It was shown that, by virtue of the low dispersion of the group velocity, the KDP crystal has some advantages over silica: a larger pulse compression coefficient, especially at a small value of the В-integral (B = 5, …, 9), lower absolute values of chirped mirror dispersion, and also a possibility to control the magnitude of nonlinearity and dispersion by changing crystal orientation.