The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the n...The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.展开更多
The third-order optical nonlinearity of two sandwich-type phthalocyaninato and porphyrinato europium com- plexes, including double- and triple-deckers （Eu[Pc（OC5H11）8]2, Eu2（Pc）（TPP）2, Pc=phthalocyanine, TPP=5,...The third-order optical nonlinearity of two sandwich-type phthalocyaninato and porphyrinato europium com- plexes, including double- and triple-deckers （Eu[Pc（OC5H11）8]2, Eu2（Pc）（TPP）2, Pc=phthalocyanine, TPP=5, 10, 15, 20- tetraphenylporphyrinate）, was investigated by using the femtosecond time-resolved optical Kerr gate method at 830 nm wavelength. Their second-order hyperpolarizability is estimated to be 0.74× 10^-30esu and 3.0× 10^-3esu respectively. This exhibits an evident enhancement in comparison with 0.47×10^-30esu for one-decker Eu（Pc）（acac） （acac=acetylacetonate）, which is also measured under the same conditions. The enhancement is attributed to the introduction of lanthanide metal to the large π-conjugated system, intermacrocycle interaction and two-photon resonance etc.展开更多
Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that f...Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared（mid-IR） regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene(～10-7cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics,potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.展开更多
Controlled stacking of different two-dimensional(2D)atomic layers hold great promise for significantly optimizing the optical properties of 2D materials and broadening their applications.Here,vertical 2DMoS_(2)/Bi_(2)...Controlled stacking of different two-dimensional(2D)atomic layers hold great promise for significantly optimizing the optical properties of 2D materials and broadening their applications.Here,vertical 2DMoS_(2)/Bi_(2)Te_(3) heterostructures with high crystallinity and optical quality have been successfully constructed,through drop-casting 2D Bi_(2)Te_(3) flakes on chemical vapor deposition(CVD)-grown MoS_(2) flakes.Based on our homebuilt micro Z-scan and pump-probe measurement,we precisely investigated and compared the nonlinear optical(NLO)performance of an individual micro-sized MoS_(2) flake before and after stacking 2D Bi_(2)Te_(3) nanoplates.Moreover,layer-dependent ultrafast carrier dynamics of CVD-grown MoS_(2) flakes were also explored.Owing to the efficient charge transfer from the monolayer(1 L)MoS_(2) to 2D Bi_(2)Te_(3),the 1L MoS_(2)/Bi_(2)Te_(3) heterostructure demonstrated excellent NLO performance with superior nonlinear saturable absorption coefficient and ultrashort carrier lifetime.Our work greatly enriches our understanding of 2D heterostructure and paves the way for designing new type of tunable 2D photonics materials by combining the optical advantages of different 2D materials.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274302,11474276 and 11674240
文摘The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.
基金Project supported by the National Key Research Program of China （Grant No TG1999075209） and the National Natural Science Foundation of China （Grant Nos 10434020, 90206003 and 60378012）.
文摘The third-order optical nonlinearity of two sandwich-type phthalocyaninato and porphyrinato europium com- plexes, including double- and triple-deckers （Eu[Pc（OC5H11）8]2, Eu2（Pc）（TPP）2, Pc=phthalocyanine, TPP=5, 10, 15, 20- tetraphenylporphyrinate）, was investigated by using the femtosecond time-resolved optical Kerr gate method at 830 nm wavelength. Their second-order hyperpolarizability is estimated to be 0.74× 10^-30esu and 3.0× 10^-3esu respectively. This exhibits an evident enhancement in comparison with 0.47×10^-30esu for one-decker Eu（Pc）（acac） （acac=acetylacetonate）, which is also measured under the same conditions. The enhancement is attributed to the introduction of lanthanide metal to the large π-conjugated system, intermacrocycle interaction and two-photon resonance etc.
基金supported by the National 973 Program of China (Grant No. 2012CB315701)the National Natural Science Foundation of China (Grant Nos. 61205125, 61222505, and 61475102)
文摘Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared（mid-IR） regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene(～10-7cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics,potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.
基金supported by the Central Government Research Programs to Guide the Local Scientific and Technological Development(No.2018L3001)National Natural Science Foundation of China(No.51872048,U1732155)Natural Science Foundation of Fujian Province(No.2020J01353)。
文摘Controlled stacking of different two-dimensional(2D)atomic layers hold great promise for significantly optimizing the optical properties of 2D materials and broadening their applications.Here,vertical 2DMoS_(2)/Bi_(2)Te_(3) heterostructures with high crystallinity and optical quality have been successfully constructed,through drop-casting 2D Bi_(2)Te_(3) flakes on chemical vapor deposition(CVD)-grown MoS_(2) flakes.Based on our homebuilt micro Z-scan and pump-probe measurement,we precisely investigated and compared the nonlinear optical(NLO)performance of an individual micro-sized MoS_(2) flake before and after stacking 2D Bi_(2)Te_(3) nanoplates.Moreover,layer-dependent ultrafast carrier dynamics of CVD-grown MoS_(2) flakes were also explored.Owing to the efficient charge transfer from the monolayer(1 L)MoS_(2) to 2D Bi_(2)Te_(3),the 1L MoS_(2)/Bi_(2)Te_(3) heterostructure demonstrated excellent NLO performance with superior nonlinear saturable absorption coefficient and ultrashort carrier lifetime.Our work greatly enriches our understanding of 2D heterostructure and paves the way for designing new type of tunable 2D photonics materials by combining the optical advantages of different 2D materials.
