In recent years, topological insulators have aroused the attention of a great number of scientists due to their unique electronic structures and peculiar physical properties. Triggered by the similar electronic struct...In recent years, topological insulators have aroused the attention of a great number of scientists due to their unique electronic structures and peculiar physical properties. Triggered by the similar electronic structures as graphene, the broadband nonlinear absorption properties of topological insulator were investigated. Moreover, the mode-locked or Q-switched fiber lasers based on topological insulator were realized for broadband operating wavelength. Here, we present an overview of the preparation, transferring, linear and nonlinear optical properties and their applications of topological insulators in pulsed fiber lasers. The pulsed fiber lasers towards mid- infrared regimes have been proposed.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
We experimentally investigated the nonlinear optical response in few-layer oxidized black phosphorus(OBP) by the femtosecond Z-scan measurement technique, and found that OBP not only possesses strong ultrafast saturab...We experimentally investigated the nonlinear optical response in few-layer oxidized black phosphorus(OBP) by the femtosecond Z-scan measurement technique, and found that OBP not only possesses strong ultrafast saturable absorption but also a nonlinear self-defocusing effect that is absent in black phosphorus(BP). The saturable absorption property originates mainly from the direct band structure, which is still maintained in OBP. The emergence of self-defocusing might originate from the combined consequences of the oxygen-induced defects in BP. Our experimental findings might constitute the first experimental evidence on how to dynamically tune its nonlinear property, offering an inroad in tailoring its optical properties through chemical modification(oxidation, introducing defects, etc.). The versatile ultrafast nonlinear optical properties(saturable absorption and self-defocusing) imply a significant potential of the layered OBP in the development of unprecedented optoelectronic devices, such as mode lockers, optical switches, laser beam shapers, and wavelength converters.展开更多
Materials with strong optical Kerr effects(OKEs)are crucial for a broad range of applications,such as all-optical data processing and quantum information.However,the underlying OKE mechanism is not clear in 2D materia...Materials with strong optical Kerr effects(OKEs)are crucial for a broad range of applications,such as all-optical data processing and quantum information.However,the underlying OKE mechanism is not clear in 2D materials.Here,we reveal key insights of the OKE associated with 2D excitons.An admirably succinct formalism is derived for predicting the spectra and the magnitude of the nonlinear refractive index(n_(2))of 2D materials.The predicted n_(2)spectra are consistent with reported experimental data and exhibit pronounced excitonic resonances,which is distinctively different from bulk semiconductors.The n_(2) value is predicted to be 3×10^(−10)cm^(2)/W for a 2D layered perovskite at low temperature as 7 K,which is four orders of magnitude larger than those of bulk semiconductors.The superior OKE induced by 2D excitons would give rise to a narrow refractive index-near-zero region for intense laser light.Furthermore,we demonstrate that the 2D layered perovskite should exhibit the best OKE efficiency(W_(FOM)=1.02,T_(FOM)=0.14)at 1550 nm,meeting the material requirements for all-optical switching.Our findings deepen the understanding of the OKE of 2D semiconducting materials and pave the way for highly efficient all-optical excitonic devices.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61475102
文摘In recent years, topological insulators have aroused the attention of a great number of scientists due to their unique electronic structures and peculiar physical properties. Triggered by the similar electronic structures as graphene, the broadband nonlinear absorption properties of topological insulator were investigated. Moreover, the mode-locked or Q-switched fiber lasers based on topological insulator were realized for broadband operating wavelength. Here, we present an overview of the preparation, transferring, linear and nonlinear optical properties and their applications of topological insulators in pulsed fiber lasers. The pulsed fiber lasers towards mid- infrared regimes have been proposed.
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National Natural Science Foundation of China(NSFC)(61435010,61505117)Science and Technology Innovation Commission of Shenzhen(KQTD2015032416270385)+1 种基金China Postdoctoral Science Foundation(2015M580731)Scienceand Technology Planning Project of Guangdong Province(2016B050501005)
文摘We experimentally investigated the nonlinear optical response in few-layer oxidized black phosphorus(OBP) by the femtosecond Z-scan measurement technique, and found that OBP not only possesses strong ultrafast saturable absorption but also a nonlinear self-defocusing effect that is absent in black phosphorus(BP). The saturable absorption property originates mainly from the direct band structure, which is still maintained in OBP. The emergence of self-defocusing might originate from the combined consequences of the oxygen-induced defects in BP. Our experimental findings might constitute the first experimental evidence on how to dynamically tune its nonlinear property, offering an inroad in tailoring its optical properties through chemical modification(oxidation, introducing defects, etc.). The versatile ultrafast nonlinear optical properties(saturable absorption and self-defocusing) imply a significant potential of the layered OBP in the development of unprecedented optoelectronic devices, such as mode lockers, optical switches, laser beam shapers, and wavelength converters.
基金National University of Singapore and Ministry of Education of the Singapore government(R-144-000-401-114,R-144-000-445-114)China Postdoctoral Science Foundation(2020M672763)+1 种基金Science and Technology Innovation Commission of Shenzhen(JCYJ20170302153323978,JCYJ20170410171958839)Education Commission of Guangdong Province(2016KCXTD006).
文摘Materials with strong optical Kerr effects(OKEs)are crucial for a broad range of applications,such as all-optical data processing and quantum information.However,the underlying OKE mechanism is not clear in 2D materials.Here,we reveal key insights of the OKE associated with 2D excitons.An admirably succinct formalism is derived for predicting the spectra and the magnitude of the nonlinear refractive index(n_(2))of 2D materials.The predicted n_(2)spectra are consistent with reported experimental data and exhibit pronounced excitonic resonances,which is distinctively different from bulk semiconductors.The n_(2) value is predicted to be 3×10^(−10)cm^(2)/W for a 2D layered perovskite at low temperature as 7 K,which is four orders of magnitude larger than those of bulk semiconductors.The superior OKE induced by 2D excitons would give rise to a narrow refractive index-near-zero region for intense laser light.Furthermore,we demonstrate that the 2D layered perovskite should exhibit the best OKE efficiency(W_(FOM)=1.02,T_(FOM)=0.14)at 1550 nm,meeting the material requirements for all-optical switching.Our findings deepen the understanding of the OKE of 2D semiconducting materials and pave the way for highly efficient all-optical excitonic devices.
