Reconfigurable surface acoustic wave(SAW)phase shifters have garnered significant attention owing to their potential applications in emerging fields such as secure wireless communication,adaptable signal processing,an...Reconfigurable surface acoustic wave(SAW)phase shifters have garnered significant attention owing to their potential applications in emerging fields such as secure wireless communication,adaptable signal processing,and intelligent sensing systems.Among various modulation methods,employing gate voltage-controlled tuning methodologies that leverage acoustoelectric interactions has proven to be an efficient modulation approach that requires a low bias voltage.However,current acoustoelectric devices suffer from limited tunability,intricate heterogeneous structures,and complex manufacturing processes,all of which impede their practical applications.In this study,we present a novel material system for voltage-tunable SAW phase shifters.This system incorporates an atomic layer deposition ZnO thin-film transistors on LiNbO_(3)structure.This structure combines the benefits of LiNbO_(3)'s high electromechanical coupling coefficient(K^(2))and ZnO's superior conductivity adjustability.Besides,the device possesses a simplified structural configuration,which is easy to fabricate.Devices with different mesa lengths were fabricated and measured,and two of the different modes were compared.The results indicate that both the maximum phase shift and attenuation of the Rayleigh mode and longitudinal leaky SAW(LLSAW)increase proportionally with mesa length.Furthermore,LLSAW with larger effective electromechanical coupling coefficients(K_(eff)^(2))values exhibits greater phase velocity shifts and attenuation coefficients,with a maximum phase velocity tuning of 1.22%achieved.It is anticipated that the proposed devices will find utility in a variety of applications necessitating tunable acoustic components.展开更多
Compression molding of glass optics is gradually becoming a viable fabrication technique for high precision optical lenses. However, refractive index variation was observed in compression molded glass lenses, which wo...Compression molding of glass optics is gradually becoming a viable fabrication technique for high precision optical lenses. However, refractive index variation was observed in compression molded glass lenses, which would contribute to image quality degradation. In this research, annealing experiments were applied to control the refractive index variation in molded glass lenses. The refractive index variations pre and post annealing experiment in molded lenses were measured by an experiment setup based on Mach-Zehnder interferometer. The experimental results showed that the refractive index variation can be controlled providing that a proper cooling process is applied during cooling.展开更多
Deep space exploration equipment faces serious thermal environment problems,and radiative heat transfer is the only thermal management method,which makes developing efficient radiative thermal management technology ur...Deep space exploration equipment faces serious thermal environment problems,and radiative heat transfer is the only thermal management method,which makes developing efficient radiative thermal management technology urgent to improve the stability and safety of equipment operation in orbit.Herein,a magnetic-controlled device is proposed by dynamically flipping the Janus coating without contact for switchable solar heating and radiative cooling purposes.The Janus coating integrates an MXene solar absorber and a PDMS/Ag radiative cooler.A device is subsequently developed for experimental demonstration,which reveals that the device exhibits temperature control effects under different temperature regions(e.g.,5 K,10 K,and 20 K)and different periods(e.g.,short-term of 30 min and 12 h).In summary,this work provides a new way of thinking for the existing dynamic radiative thermal management technology based on the magnetic-controlled idea,showing considerable potential for radiative thermal management and serving for space equipment,including satellites,space stations,and spacecraft.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos:62122004 and 62274082)Beijing Natural Science Foundation(Grant No.Z210006)+5 种基金Hong Kong Research Grant Council(Grant Nos.27206321,17205922,17212923,C1009-22G and T45-701/22-R)Shenzhen Science and Technology Innovation Commission(SGDX20220530111405040,JCYJ20220530115411025 and JCYJ20210324120409025)Research on mechanism of source/drain ohmic contact and the related Ga N p-FET(Grant No:2023A1515030034)Research on high-reliable Ga N power device and the related industrial power system(Grant No:HZQB-KCZYZ-2021052)supported by ACCESS-AI Chip Center for Emerging Smart Systems,sponsored by Innovation and Technology Fund(ITF),Hong Kong SARthe assistance of SUSTech Core Research Facilities。
文摘Reconfigurable surface acoustic wave(SAW)phase shifters have garnered significant attention owing to their potential applications in emerging fields such as secure wireless communication,adaptable signal processing,and intelligent sensing systems.Among various modulation methods,employing gate voltage-controlled tuning methodologies that leverage acoustoelectric interactions has proven to be an efficient modulation approach that requires a low bias voltage.However,current acoustoelectric devices suffer from limited tunability,intricate heterogeneous structures,and complex manufacturing processes,all of which impede their practical applications.In this study,we present a novel material system for voltage-tunable SAW phase shifters.This system incorporates an atomic layer deposition ZnO thin-film transistors on LiNbO_(3)structure.This structure combines the benefits of LiNbO_(3)'s high electromechanical coupling coefficient(K^(2))and ZnO's superior conductivity adjustability.Besides,the device possesses a simplified structural configuration,which is easy to fabricate.Devices with different mesa lengths were fabricated and measured,and two of the different modes were compared.The results indicate that both the maximum phase shift and attenuation of the Rayleigh mode and longitudinal leaky SAW(LLSAW)increase proportionally with mesa length.Furthermore,LLSAW with larger effective electromechanical coupling coefficients(K_(eff)^(2))values exhibits greater phase velocity shifts and attenuation coefficients,with a maximum phase velocity tuning of 1.22%achieved.It is anticipated that the proposed devices will find utility in a variety of applications necessitating tunable acoustic components.
文摘Compression molding of glass optics is gradually becoming a viable fabrication technique for high precision optical lenses. However, refractive index variation was observed in compression molded glass lenses, which would contribute to image quality degradation. In this research, annealing experiments were applied to control the refractive index variation in molded glass lenses. The refractive index variations pre and post annealing experiment in molded lenses were measured by an experiment setup based on Mach-Zehnder interferometer. The experimental results showed that the refractive index variation can be controlled providing that a proper cooling process is applied during cooling.
基金supported by the National Natural Science Foundation of China(No.52476225,No.52130601)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the University of Science and Technology of China-Southwest University of Science and Technology Counterpart Cooperation and Development Joint Fund(KY2090002002).
文摘Deep space exploration equipment faces serious thermal environment problems,and radiative heat transfer is the only thermal management method,which makes developing efficient radiative thermal management technology urgent to improve the stability and safety of equipment operation in orbit.Herein,a magnetic-controlled device is proposed by dynamically flipping the Janus coating without contact for switchable solar heating and radiative cooling purposes.The Janus coating integrates an MXene solar absorber and a PDMS/Ag radiative cooler.A device is subsequently developed for experimental demonstration,which reveals that the device exhibits temperature control effects under different temperature regions(e.g.,5 K,10 K,and 20 K)and different periods(e.g.,short-term of 30 min and 12 h).In summary,this work provides a new way of thinking for the existing dynamic radiative thermal management technology based on the magnetic-controlled idea,showing considerable potential for radiative thermal management and serving for space equipment,including satellites,space stations,and spacecraft.
