Whispering-gallery-mode(WGM)microresonators can greatly enhance light-matter interaction,making them indispensable units for frequency conversion in nonlinear optics.Efficient nonlinear wave mixing in microresonators ...Whispering-gallery-mode(WGM)microresonators can greatly enhance light-matter interaction,making them indispensable units for frequency conversion in nonlinear optics.Efficient nonlinear wave mixing in microresonators requires stringent simultaneous optical resonance and phase-matching conditions.Thus,it is challenging to achieve efficient frequency conversion over a broad bandwidth.Here,we demonstrate broadband second-harmonic generation(SHG)in the x-cut thinfilm lithium niobate(TFLN)microdisk with a quality factor above 107by applying the cyclic quasi-phase-matching(CQPM)mechanism,which is intrinsically applicable for broadband operation.Broadband SHG of continuous-wave laser with a maximum normalized conversion efficiency of~15%/m W is achieved with a bandwidth spanning over 100 nm in the telecommunication band.Furthermore,broadband SHG of femtosecond lasers,supercontinuum lasers,and amplified spontaneous emission in the telecommunication band is also experimentally observed.The work is beneficial for integrated nonlinear photonics devices like frequency converters and optical frequency comb generator based on second-order nonlinearity on the TFLN platform.展开更多
Image reconstruction through the opaque medium has great significance in fields of biophotonics,optical imaging,mesoscopic physics,and optical communications.Previous researches are limited in the simple linear scatte...Image reconstruction through the opaque medium has great significance in fields of biophotonics,optical imaging,mesoscopic physics,and optical communications.Previous researches are limited in the simple linear scattering process.Here,we develop a nonlinear speckle decoder network,which can reconstruct the phase information of the fundamental frequency wave via the nonlinear scattering signal.Further,we validate the ability of our model to recover simple and complex structures by using MNIST and CIFAR data sets,respectively.We then show that the model is able to restore the image information through different sets of nonlinear diffusers and reconstruct the image of a kind of completely unseen object category.The proposed method paves the way to nonlinear scattering imaging and information encryption.展开更多
Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus ...Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus light through inhomogeneous media, which is vital for optical imaging, communication,therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamicprocesses in the linear regime. However, the implementation of such a method for controlling light in nonlinearmedia is still a challenge and has been unexplored until now. We report a method to determine the SM ofnonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility inwavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media.Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinearimaging, microscopic object tracking, and complex environment quantum information processing.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12074252,12192252,and 62022058)the National Key Research and Development Program of China(No.2022YFA1205101)+1 种基金the Shanghai Municipal Science and Technology Major Project(No.2019SHZDZX01-ZX06)and the Yangyang Development Fund。
文摘Whispering-gallery-mode(WGM)microresonators can greatly enhance light-matter interaction,making them indispensable units for frequency conversion in nonlinear optics.Efficient nonlinear wave mixing in microresonators requires stringent simultaneous optical resonance and phase-matching conditions.Thus,it is challenging to achieve efficient frequency conversion over a broad bandwidth.Here,we demonstrate broadband second-harmonic generation(SHG)in the x-cut thinfilm lithium niobate(TFLN)microdisk with a quality factor above 107by applying the cyclic quasi-phase-matching(CQPM)mechanism,which is intrinsically applicable for broadband operation.Broadband SHG of continuous-wave laser with a maximum normalized conversion efficiency of~15%/m W is achieved with a bandwidth spanning over 100 nm in the telecommunication band.Furthermore,broadband SHG of femtosecond lasers,supercontinuum lasers,and amplified spontaneous emission in the telecommunication band is also experimentally observed.The work is beneficial for integrated nonlinear photonics devices like frequency converters and optical frequency comb generator based on second-order nonlinearity on the TFLN platform.
基金National Natural Science Foundation of China(12192252,12374314)National Key Research and Development Program of China(2023YFA1407200).
文摘Image reconstruction through the opaque medium has great significance in fields of biophotonics,optical imaging,mesoscopic physics,and optical communications.Previous researches are limited in the simple linear scattering process.Here,we develop a nonlinear speckle decoder network,which can reconstruct the phase information of the fundamental frequency wave via the nonlinear scattering signal.Further,we validate the ability of our model to recover simple and complex structures by using MNIST and CIFAR data sets,respectively.We then show that the model is able to restore the image information through different sets of nonlinear diffusers and reconstruct the image of a kind of completely unseen object category.The proposed method paves the way to nonlinear scattering imaging and information encryption.
基金supported in part by the National Key R&D Program of China (No. 2018YFA0306301)the National Natural Science Foundation of China (Nos. 12192252, 62022058, 12074252, and 12004245)+2 种基金the Shanghai Municipal Science and Technology Major Project (No. 2019SHZDZX01ZX06)the Shanghai Rising-Star Program (No. 20QA1405400)the Yangyang Development Fund.
文摘Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus light through inhomogeneous media, which is vital for optical imaging, communication,therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamicprocesses in the linear regime. However, the implementation of such a method for controlling light in nonlinearmedia is still a challenge and has been unexplored until now. We report a method to determine the SM ofnonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility inwavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media.Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinearimaging, microscopic object tracking, and complex environment quantum information processing.
