Sensitive mid-infrared(MIR)detection is in high demand in various applications,ranging from remote sensing,infrared surveillance,and environmental monitoring to industrial inspection.Among others,upconversion infrared...Sensitive mid-infrared(MIR)detection is in high demand in various applications,ranging from remote sensing,infrared surveillance,and environmental monitoring to industrial inspection.Among others,upconversion infrared detectors have recently attracted increasing attention due to their advantageous features of high sensitivity,fast response,and room-temperature operation.However,it remains challenging to realize high-performance passive MIR sensing due to the stringent requirement of high-power continuouswave pumping.Here,we propose and implement a high-efficiency and low-noise MIR upconversion detection system based on pumping enhancement via a low-loss optical cavity.Specifically,a singlelongitudinal-mode pump at 1064 nm is significantly enhanced by a factor of 36,thus allowing for a peak conversion efficiency of up to 22%at an intracavity average power of 55 W.The corresponding noise equivalent power is achieved as low as 0.3 fW∕Hz^(1∕2),which indicates at least a 10-fold improvement over previous results.Notably,the involved single-frequency pumping would facilitate high-fidelity spectral mapping,which is particularly attractive for high-precision MIR upconversion spectroscopy in photonstarved scenarios.展开更多
Biocompatible NaREF_4（RE=0.4Y＋0.4La＋0.2（Yb,Er,Tm）（molar ratio）） upconversion nanoparticles（UCNPs） with strong visible fluorescence were synthesized by a solvothermal method and subsequent surface modificatio...Biocompatible NaREF_4（RE=0.4Y＋0.4La＋0.2（Yb,Er,Tm）（molar ratio）） upconversion nanoparticles（UCNPs） with strong visible fluorescence were synthesized by a solvothermal method and subsequent surface modification. Modulated upconversion luminescence emission spectra were obtained via changing the doping. In vitro and in vivo bioimagings were carried out with shrimps. The upconversion nanoprobes with an acidic/PEG hybrid ligand could quickly capture the basic Rhodamine-B（RB） in shrimp cells and formed a close UCNPs@RB system. The residual organic dye RB in shrimps could be detected on the basis of luminescent resonance energy transfer（LRET）. It could be rapidly addressed based on LRET detection that RB residue existed in the shrimps after incubating in the aqueous solution of RB higher than 3 μg/m L for 12 h.展开更多
We present an inexpensive technique to obtain a three-dimensional(3D) millimeter wave(MMW) and terahertz(THz) image using upconversion. In this work we describe and demonstrate a method for upconversion of MMW/THz rad...We present an inexpensive technique to obtain a three-dimensional(3D) millimeter wave(MMW) and terahertz(THz) image using upconversion. In this work we describe and demonstrate a method for upconversion of MMW/THz radiation to the visual band using a very inexpensive miniature glow discharge detector(GDD) and a silicon photodetector. We present MMW/THz upconversion images based on measuring the visual light emitting from the GDD rather than its electrical current. The results show better response time and better sensitivity compared to the electronic detection performed previously. Furthermore, in this work we perform frequency modulation continuous wave(FMCW) radar detection based on this method using a GDD lamp, with a photodetector to measure GDD light emission. By using FMCW detection, the range in addition to the intensity at each pixel can be obtained,thus yielding the 3D image. The GDD acts as a heterodyne mixer not only electronically but also optically. The suggested 3D upconversion technique using the GDD is simple and inexpensive and has better performance compared to other MMW/THz imaging systems suggested in the literature. This method provides minimum detectable signal power that is about 6 orders of magnitude better than similar plasma systems due to the very large internal signal gain deriving from the much smaller electrode separation and resulting in much higher plasma electric field.展开更多
基金supported by the National Key Research and Development Program(Grant No.2021YFB2801100)the National Natural Science Foundation of China(Grant Nos.62175064,62235019,62035005,and 12022411)+3 种基金the Shanghai Pilot Program for Basic Research(Grant No.TQ20220104)the Natural Science Foundation of Chongqing(Grant Nos.CSTB2023NSCQ-JQX0011,CSTB2022NSCQ-MSX0451,and CSTB2022NSCQ-JQX0016)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)the Fundamental Research Funds for the Central Universities.
文摘Sensitive mid-infrared(MIR)detection is in high demand in various applications,ranging from remote sensing,infrared surveillance,and environmental monitoring to industrial inspection.Among others,upconversion infrared detectors have recently attracted increasing attention due to their advantageous features of high sensitivity,fast response,and room-temperature operation.However,it remains challenging to realize high-performance passive MIR sensing due to the stringent requirement of high-power continuouswave pumping.Here,we propose and implement a high-efficiency and low-noise MIR upconversion detection system based on pumping enhancement via a low-loss optical cavity.Specifically,a singlelongitudinal-mode pump at 1064 nm is significantly enhanced by a factor of 36,thus allowing for a peak conversion efficiency of up to 22%at an intracavity average power of 55 W.The corresponding noise equivalent power is achieved as low as 0.3 fW∕Hz^(1∕2),which indicates at least a 10-fold improvement over previous results.Notably,the involved single-frequency pumping would facilitate high-fidelity spectral mapping,which is particularly attractive for high-precision MIR upconversion spectroscopy in photonstarved scenarios.
基金Project supported by the National Natural Science Foundation of China(61376076,61674056,61675067,61575062,51275167,61377024)supported by the Scientific Research Fund of Hunan Provincial Education Department(16A072)
文摘Biocompatible NaREF_4（RE=0.4Y＋0.4La＋0.2（Yb,Er,Tm）（molar ratio）） upconversion nanoparticles（UCNPs） with strong visible fluorescence were synthesized by a solvothermal method and subsequent surface modification. Modulated upconversion luminescence emission spectra were obtained via changing the doping. In vitro and in vivo bioimagings were carried out with shrimps. The upconversion nanoprobes with an acidic/PEG hybrid ligand could quickly capture the basic Rhodamine-B（RB） in shrimp cells and formed a close UCNPs@RB system. The residual organic dye RB in shrimps could be detected on the basis of luminescent resonance energy transfer（LRET）. It could be rapidly addressed based on LRET detection that RB residue existed in the shrimps after incubating in the aqueous solution of RB higher than 3 μg/m L for 12 h.
基金North Atlantic Treaty Organization(NATO)Science for Peace and Security(SPS)Program(MD.SFPP984775)
文摘We present an inexpensive technique to obtain a three-dimensional(3D) millimeter wave(MMW) and terahertz(THz) image using upconversion. In this work we describe and demonstrate a method for upconversion of MMW/THz radiation to the visual band using a very inexpensive miniature glow discharge detector(GDD) and a silicon photodetector. We present MMW/THz upconversion images based on measuring the visual light emitting from the GDD rather than its electrical current. The results show better response time and better sensitivity compared to the electronic detection performed previously. Furthermore, in this work we perform frequency modulation continuous wave(FMCW) radar detection based on this method using a GDD lamp, with a photodetector to measure GDD light emission. By using FMCW detection, the range in addition to the intensity at each pixel can be obtained,thus yielding the 3D image. The GDD acts as a heterodyne mixer not only electronically but also optically. The suggested 3D upconversion technique using the GDD is simple and inexpensive and has better performance compared to other MMW/THz imaging systems suggested in the literature. This method provides minimum detectable signal power that is about 6 orders of magnitude better than similar plasma systems due to the very large internal signal gain deriving from the much smaller electrode separation and resulting in much higher plasma electric field.
