Chalcogenide glass (ChG) is an attractive material for highly efficient nonlinear photonics,which can cover an ultrabroadband wavelength window from the near-visible to the footprint infrared region. However,it remain...Chalcogenide glass (ChG) is an attractive material for highly efficient nonlinear photonics,which can cover an ultrabroadband wavelength window from the near-visible to the footprint infrared region. However,it remains a challenge to implement highly-efficient and low-threshold optical parametric processes in chip-scale ChG devices due to thermal and light-induced instabilities as well as a high-loss factor in ChG films. Here,we develop a systematic fabrication process for high-performance photonic-chip-integrated ChG devices,by which planarintegrated ChG microresonators with an intrinsic quality (Q) factor above 1 million are demonstrated. In particular,an in situ light-induced annealing method is introduced to overcome the longstanding instability underlying ChG film. In high-Q ChG microresonators,optical parametric oscillations with threshold power as low as 5.4 mW are demonstrated for the first time,to our best knowledge. Our results would contribute to efforts of making efficient and low-threshold optical microcombs not only in the near-infrared as presented but more promisingly in the midinfrared range.展开更多
Fast and sensitive air-coupled ultrasound detection is essential for many applications such as radar,ultrasound imaging,and defect detection.Here we present a novel approach based on a digital optical frequency comb(D...Fast and sensitive air-coupled ultrasound detection is essential for many applications such as radar,ultrasound imaging,and defect detection.Here we present a novel approach based on a digital optical frequency comb(DOFC)technique combined with high-Q optical microbubble resonators(MBRs).DOFC enables precise spectroscopy on resonators that can trace the ultrasound pressure with its resonant frequency shift with femtometer resolution and sub-microsecond response time.The noise equivalent pressure of air-coupled ultrasound as low as 4.4 m Pa∕pHz is achieved by combining a high-Q(~3×10~7)MBR with the DOFC method.Moreover,it can observe multi-resonance peaks from multiple MBRs to directly monitor the precise spatial location of the ultrasonic source.This approach has a potential to be applied in 3 D air-coupled photoacoustic and ultrasonic imaging.展开更多
基金National Key Research and Development Program of China (2019YFA0706301)Key Project in Broadband Communication and New Network of the Ministry of Science and Technology (MOST)(2018YFB1801003)+3 种基金National Natural Science Foundation of China (61975242,U2001601)Key Project for Science and Technology of Guangzhou City (201904020048)Science and Technology Planning Project of Guangdong Province (2019A1515010774)Science Foundation of Guangzhou City (202002030103)。
文摘Chalcogenide glass (ChG) is an attractive material for highly efficient nonlinear photonics,which can cover an ultrabroadband wavelength window from the near-visible to the footprint infrared region. However,it remains a challenge to implement highly-efficient and low-threshold optical parametric processes in chip-scale ChG devices due to thermal and light-induced instabilities as well as a high-loss factor in ChG films. Here,we develop a systematic fabrication process for high-performance photonic-chip-integrated ChG devices,by which planarintegrated ChG microresonators with an intrinsic quality (Q) factor above 1 million are demonstrated. In particular,an in situ light-induced annealing method is introduced to overcome the longstanding instability underlying ChG film. In high-Q ChG microresonators,optical parametric oscillations with threshold power as low as 5.4 mW are demonstrated for the first time,to our best knowledge. Our results would contribute to efforts of making efficient and low-threshold optical microcombs not only in the near-infrared as presented but more promisingly in the midinfrared range.
基金Key Project in Broadband Communication and New Network of the Ministry of Science and Technology(MOST)(2018YFB1801003)National Natural Science Foundation of China(61435006,61490715,61525502,61975242)+2 种基金Local Innovation and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)Science and Technology Planning Project of Guangdong Province(2017B010123005,2018BT010114002)We thank Prof. Xuefeng Zhu andDr. Pengqi Li at Huazhong University of Science andTechnology for testing the data of pressure in air as a functionof the driving voltage. We also thank Prof. Xuming Zhangat Hong Kong Polytechnic University and Prof. Hairun Guoat Shanghai University for discussing the results of MBRsusing DOFC method.
文摘Fast and sensitive air-coupled ultrasound detection is essential for many applications such as radar,ultrasound imaging,and defect detection.Here we present a novel approach based on a digital optical frequency comb(DOFC)technique combined with high-Q optical microbubble resonators(MBRs).DOFC enables precise spectroscopy on resonators that can trace the ultrasound pressure with its resonant frequency shift with femtometer resolution and sub-microsecond response time.The noise equivalent pressure of air-coupled ultrasound as low as 4.4 m Pa∕pHz is achieved by combining a high-Q(~3×10~7)MBR with the DOFC method.Moreover,it can observe multi-resonance peaks from multiple MBRs to directly monitor the precise spatial location of the ultrasonic source.This approach has a potential to be applied in 3 D air-coupled photoacoustic and ultrasonic imaging.
