用于超快宽带激光防护的共轭扭曲并苯高性能光限幅材料

高性能的光限幅对激光防护应用来说非常重要。虽然光限幅相关的研究持续了几十年,但是绝大多数的已知光限幅材料无法兼顾低限幅阈值、高线性透过率和宽带、超快响应。从实验和理论上报道一种基于共轭扭曲并苯分子的多功能光限幅材料。研究结果显示,借助等效三光子吸收,该材料能够在480~700 nm的光谱范围内实现光限幅并具备快速的响应能力。此外,样品还同时具备低限幅阈值（0.15 J/cm2）和极高的线性透过率（532 nm时92%）。该光限幅材料集以上所有优点于一身,在用于人眼和光子器件的超快激光防护领域具有巨大的前景。     

半导体纳米粒子Bi2S3和NiS的非线性吸收特性

测量了两种纳米粒子Bi2S3和NiS的光限幅特性和非线性光学响应,测量了非线性吸收特性,数值模拟计算了Bi2S3的非线性吸收系数β≈9cm/GW,NiS非线性吸收系数β≈8cm/GW.     

半导体纳米粒子Bi2S3和NiS的非线性吸收特性

测量了两种纳米粒子Bi2S3和NiS的光限幅特性和非线性光学响应，测量了非线性吸收特性，数值模拟计算了Bi2S3的非线性吸收系数β≈9cm/GW, NiS非线性吸收系数β≈8cm/GW.     

半导体纳米粒子Bi2S3和NiS的非线性吸收特性

测量了两种纳米粒子Bi2S3和NiS的光限幅特性和非线性光学响应,测量了非线性吸收特性,数值模拟计算了Bi2S3的非线性吸收系数β≈9cm/GW,NiS非线性吸收系数β≈8cm/GW.     

半导体纳米粒子Bi2S3和NiS的光限幅特性研究

研究了Bi2S2和NiS半导体纳米粒子的光限幅特性,测得了Bi2S3非线性阈值为0.11 J/cm2,NiS的非线性阈值为0.21 J/cm2.对两种样品进行了开孔Z-scan的实验,计算可知Bi2S3非线性吸收系数β≈9 cm/GW,NiS的非线性吸收系数β≈8 cm/GW.在NiS半导体纳米粒子的乙醇溶液进行闭孔Z-scan时,发现样品有自聚焦的特性,也就是说样品的非线性折射率系数n2＞O,计算得y≈2.66×104 cm2/GW.     

ZnS/ZnSe迭层式波导光栅的光调制特性

报道了在ZnS/ZnSe非线性迭层式波导光栅中实现的光控反射特性和光学限制效应,在控制光强为2.60×105W/cm2的Ar 激光作用下,得到对应于二阶Bragg衍射的衍射光偏转角为-2°,相应的折射率变化为-0.049,并得到该材料的非线性折射率系数为-1.9×10-7cm2/W,同时得到其光学限制阈值约为140mW(1.42×105W/cm2),限幅阈值为24mW。     

金属Ru富勒烯化合物光学非线性研究

用 Z扫描技术研究了金属 Ru富勒烯 (C6 0 )化合物的非线性光学性质。测得样品在波长 5 32 nm处的非线性折射率为 n2 =1.5 5× 10 - 4cm2 / GW,激发态吸收截面为 σex=3.32× 10 - 1 7cm2。光限幅测量表明 ,该材料还具有较强的光限幅特性     

四枯丁苯氧基氯代酞菁铟激光防护材料

纳秒级脉冲激光对战场中广泛使用的光电传感器构成了严重威胁。光限幅材料在阻止强激光通过的同时,不影响低能量信号光的通过,是目前激光防护领域的研究热点。针对可见-近红外波段光电传感器强激光防护应用需求,在金属酞菁化合物基础上,基于增强其共轭体系电子云密度的设计思想制备了一种新型高性能光限幅材料——四枯丁苯氧基氯代酞菁铟,并对其进行了测试表征。瞬态吸收光谱实验表明,四枯丁苯氧基氯代酞菁铟具有很强且长寿命的激发态吸收。光限幅性能测试证明其光限幅启动阈值为8 mJ/cm²,光限幅阈值为0.06 J/cm²,损伤阈值大于4 J/cm²,当输入能流达到3 J/cm²时,光限幅器件透过率下降到6%。由测试结果可以看出,该材料光限幅启动阈值及光限幅阈值低,损伤阈值高,可见-近红外波段线性透过率高,具有优异的光限幅性能,在光电系统激光防护中具有较高的应用前景。     

基于超快光克尔效应的超短脉冲光限幅器

超短脉冲激光因其独特的传播性质,在光电对抗领域具有重要的应用潜力。针对传统光限幅器件在超短脉冲激光限幅防护领域中存在的若干问题,提出一种基于超快光克尔效应的超短脉冲光限幅器。该限幅技术利用超短脉冲在非线性介质中诱导非线性偏振椭圆旋转(NER)效应,可实现超低阈值的光限幅输出,同时将非线性偏振椭圆旋转和自聚焦效应相结合,可保证器件在较大动态能量范围内具备限幅功能,该器件具备响应速度快、适用光谱范围宽的优点。系统阐述了NER效应的基本原理,并利用飞秒脉冲激光验证了基于NER和自聚焦效应的光限幅器的限幅性能。     

一种新型金属有机化合物的非线性光学特性研究

利用z扫描方法研究了一种新型杂环类化合物的非线性光学特性,该化合物是以金属离子为中心具有π电子结构的配合物,在488nm波长激发下,该化合物具有自散焦特性,测得其二氯甲烷溶液的热致三阶非线性极化率为-1.33×10-4esu,并在此基础上初步研究了它的光限幅特性,其对488nm连续激光的限幅阈值为25W/cm2,限幅机理是基于激发态的反饱和吸收效应。结果表明,该化合物是一种非常有前途的非线性光学材料。     

新型金属铟酞菁酯的光学非线性和光限幅特性

文中介绍了一种新型金属铟酞菁酯化合物的合成方法。为了研究该化合物的非线性光学性质,在532 nm波长下,分别使用皮秒和纳秒脉冲对样品进行了Z扫描测试。实验结果表明该样品在皮秒和纳秒时域都有很强的反饱和吸收以及非线性正折射。对Z扫描实验数据进行数值模拟分别得到样品在皮秒和纳秒脉冲作用下等效的三阶非线性吸收系数和三阶折射率:ps=4.110-11m/W,ps=4.510-19m2/W 以及ps=5.110-9m/W,ps=1.510-16m2/W。分析讨论了激发态能及对该化合物非线性光学性质的影响,并使用纳秒脉冲激光对样品进行了光限幅测试,在T/T0=0.5时,阈值为2.0J/cm2,实验结果表明该样品拥有良好的光限幅性能。     

Increase of the SBS threshold in a short highly nonlinear fiber byapplying a temperature distribution

We evaluate numerically and experimentally the stimulated Brillouin scattering (SBS) threshold increase for a short, highly nonlinear GeO₂-doped fiber by applying different temperature distributions along the fiber. The temperature coefficient for the Brillouin frequency downshift is measured to 1.2 MHz/°C. A threefold SBS threshold increase is obtained for a 100-m long highly nonlinear fiber with a 140°C temperature gradient. The proposed scheme is implemented in a wavelength converter based on fiber optical four-wave mixing (FWM). The SBS suppression scheme shows negligible influence on the FWM efficiency as well as the wavelength conversion bandwidth. The temperature coefficient for the zero dispersion wavelength is measured to 0.062 nm/°C     

非线性光栅自调制光限幅器件研究

研制出一种三角槽型透明高分子聚合物光栅与该聚合物平板间填充有机非线性光学液体的夹层结构器件，具有非线性自调制光限幅功能。实验测得该器件对较弱的532nm波长的YAG倍频激光透过率大于60％。对较强激光透过率小于2％～3％。理论预期在激光波长400-700nm都有光限幅特性。且愈靠近532nm波长。激光限幅功能愈强。首次从实验上验证了该非线性光栅具有自适应宽带光限幅的功能。它不仅可以实现可调谐光限幅。且对所设计的激光波长，达到能量低于人眼安全阈值的高效激光防护成为可能。     

Protonation effect on the nonlinear absorption, nonlinear refraction and optical limiting properties of tetraphenylporphyrin

Nonlinear optical properties of tetraphenylporphyrin (H2TPP) and protonated tetraphenylporphyrin (H4TPP2+) in toluene were investigated by Z-scan technique using a nanosecond laser with 5 ns pulse at 532 nm. Results show that H4TPP2+ exhibits weaker nonlinear refraction but enhanced reverse saturable absorption (RSA) and optical limiting performance in comparison with pristine H2TPP. Since no nonlinear scattering is observed in H4TPP2+ under low input fluence, and H4TPP2+ exhibits weaker nonlinear scattering signals than H2TPP under high input fluence, the enhancement of RSA and optical limiting performance can be attributed to the larger ratio of excited state absorption cross-section to that of the ground state of H4TPP2+. H4TPP2+ also exhibits superior optical limiting performance, even better than the benchmark RSA material C60.     

不同浓度Ti:Bi2Te3的调Q光纤激光器

基于二维材料的非线性光开关是调Q光纤激光器的核心器件,二维材料光开关的浓度会直接影响其非线性光学吸收特性,从而改变脉冲的时域特性。因此,针对二维材料浓度对调Q光脉冲的影响进行了研究,并通过实验制作了基于不同浓度Ti: Bi₂Te₃可饱和吸收光开关,分析了Ti: Bi₂Te₃浓度对非线性光学吸收特性的影响,获得了调Q光脉冲的调制深度、脉冲宽度、重复频率和单脉冲能量随不同浓度Bi₂Te₃的变化关系。最终,针对谐振腔参数对Ti:Bi₂Te₃浓度进行优化,在泵浦功率为71 mW时,获得了中心波长为1 560 nm、脉冲宽度为8 μs,重复频率为14.2 kHz、平均输出功率2.15 mW、对应单脉冲能量为151.4 nJ的脉冲输出。     

Engineering Aggregation-Resistant MXene Nanosheets As Highly Conductive and Stable Inks for All-Printed Electronics

MXenes are interesting 2D materials that have been considered as attractive frontier materials for potential applications in the fields of energy and electronic devices due to their excellent optoelectronic properties including metallic conductivity and high optical transparency. However, it is still challenging to achieve compatibility for the as-synthesized MXene nanosheets with simple solution-deposition and patterning processes because of their limited solubility in many solvents. Here, a promising strategy is developed for obtaining alcohol-dispersible MXene nanosheets suitable for all-printed electronics while enhancing their electrical conductivity. This strategy includes a trifluoroacetic acid treatment—applied in order to contribute to the modification of intercalants between the MXene nanosheets—and achieves long-term dispersion of the MXene in alcoholic media and balanced jetting conditions during the electrohydrodynamic printing process. Furthermore, the high conductivity levels of the treated MXenes allow their printed patterns to be applied as gate and source/drain electrodes in all-printed logic circuits, displaying good and robust operation in transistors, inverters, and NAND, and NOR logic gates. This study provides a promising approach for modifying MXene nanosheets with the purpose of achieving desirable properties suitable for large-area printing processes, suggesting the feasibility of using MXene in practical applications involving all-printed electronics.     

电子辐照制备二维锑烯光限幅材料

块状材料锑粒通过液相剥离成功制备了锑烯纳米片。采用扫描电镜、紫外-可见吸收光谱和拉曼光谱对所制锑烯进行了表征,制备的锑烯纳米片展现出从紫外区到可见光区的宽谱吸收,并且展现出锑的拉曼特征峰,微观结构上展示出二维纳米片状的独特结构。利用Z-扫描技术对所制样品的三阶非线性光学性质测试发现,在脉冲宽度为4 ns、波长为532 nm的激光光源激发下,锑烯展示出饱和吸收的性质,其非线性吸收系数为-7.8610-11 m/W。通过对样品进行电子辐照,成功获取了具有光限幅性质的二维锑烯。辐照后的锑烯展示出反饱和吸收的性质,非线性吸收系数为8.6910-11 m/W。     

利用光纤的非线性效应产生多波长超短光脉冲

采用光纤环激光器为光源,色散位移光纤为非线性介质,利用光纤的非线性效应产生超连续（ｓｕ－ｐｅｒｃｏｎｔｉｎｕｕｍ）光谱信号,光谱宽度超过４０ｎｍ,采用Ｆ－Ｐ腔和可调谐滤波器滤波后成功地得到了１２个不同波长的超短光脉冲,每个波长的光脉冲重复频率为２．５ＧＨｚ,相邻波长间距为３．５ｎｍ。     

Q-switched giant pulsed erbium-doped all-fiber laser withV2ZnC MAX phase saturable absorber

MXenes, drawn from MAX phases, are special two-dimensional substances with numerous advantages in nonlinear optics, specifically in giant and ultrashort pulsed-laser applications. Ti3C2Tx and Ti2CTx nanosheets however rapidly deteriorate under ambient conditions, limiting their applications. This paper demonstrates how excellent modulation depth of one of the MAX phase compounds vanadium zinc carbide (V2ZnC) makes it a brilliant saturable absorber (SA) in passively Q-switched all-fiber pulsed lasers, integrated such that a 16.73-µm V2ZnC-polyvinyl alcohol (PVA) thin film acts as SA in the laser. Saturable and non-saturable absorptions were found to be 13.2% and 10.47%, while saturation optical intensity and modulation depth were 6.25 kW/cm2 and 12.43%, respectively, illustrating the optical nonlinearity. The superiority of MAX-PVA, fabricated in four distinct ratios, was demonstrated by the fact that it self-starts a giant pulsed laser at pump power as low as 22.5 mW and firmly accomplished 120.6 kHz repetition rate with a pulse width of 2.08 µs. It is a fine SA for the use of pulsed-laser production using all-fiber laser due to fabrication simplicity and great optical, thermophysical, and mechanical qualities.