The field of high-bandwidth holography has been extensively studied over the past decade.Orbital angular momentum(OAM)holography,which utilizes vortex beams with theoretically unbounded OAM modes as information carrie...The field of high-bandwidth holography has been extensively studied over the past decade.Orbital angular momentum(OAM)holography,which utilizes vortex beams with theoretically unbounded OAM modes as information carriers,showcases the large capacitance of hologram storage.However,OAM holography has been limited to a single wavelength,restricting its potential for full-color holography and displays.In this study,we propose wavelength and OAM multiplexed holography that utilizes the multiple dimensions of light—wavelength and OAM—to provide a multi-color platform that expands the information capacity of holographic storage devices.The proposed wavelength-OAM multiplexed holography is physically realized by a metasurface,the state-of-the-art optical element consisting of an array of artificially engineered nanostructures.Hydrogenated silicon meta-atoms,the constituents of the metasurface,are engineered to possess wavelength selectivity by tailoring the dispersion of polarization conversion.These meta-atoms are used to encode the calculated OAM-preserved phase maps based on our design.The sampling grid of the phase map is rotated by 45°,which effectively suppress higher-order diffraction,providing a great strategy for achieving large field-of-view(FOV)holography.We successfully demonstrate six holographic images that are selectively reconstructed under the illumination of light with specific wavelengths(λ=450,635 nm)and topological charges(l=-2,0,2),without high-order diffraction.Our work suggests that ultrathin meta-holograms can potentially realize ultrahigh-bandwidth full-color holography and holographic video displays with large FOV.展开更多
Multiphase flows involving liquid droplets in association with gas flow occur in many industrial and sci- entific applications. Recent work has demonstrated the feasibility of using optical techniques based on laser e...Multiphase flows involving liquid droplets in association with gas flow occur in many industrial and sci- entific applications. Recent work has demonstrated the feasibility of using optical techniques based on laser extinction to simultaneously measure vapor concentration and temperature and droplet size and loading. This work introduces the theoretical background for the optimal design of such laser extinction techniques, termed WMLE （wavelength-multiplexed laser extinction）. This paper focuses on the devel- opment of WMLE and presents a systematic methodology to guide the selection of suitable wavelengths and optimize the performance of WMLE for specific applications. WMLE utilizing wavelengths from 0.5 to 10 ixm is illustrated for droplet size and vapor concentration measurements in an example of water spray, and is found to enable unique and sensitive Sauter mean diameter measurement in the range of ~1-15 ~m along with accurate vapor detection. A vapor detection strategy based on differential absorp- tion is developed to extend accurate measurement to a significantly wider range of droplet loading and vapor concentration as compared to strategies based on direct fixed-wavelength absorption. Expected performance of the sensor is modeled for an evaporating spray. This work is expected to lay the ground- work for implementing optical sensors based on WMLE in a variety of research and industrial applications involving multi-phase flows.展开更多
基金supported by the Samsung Research Funding&Incubation Center for Future Technology grant(SRFC-IT1901-52)funded by Samsung ElectronicsJ.R.acknowledges the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCO+4 种基金the National Research Foundation(NRF)grant(RS-2024-00356928)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentthe NRF Sejong Science fellowships(RS-2023-00209560,RS-2023-00252778)respectively,funded by the MSIT of the Korean government.J.J.acknowledges the Hyundai Motor Chung Mong-Koo fellowship.J.K.acknowledges the Asan Foundation Biomedical Science fellowship,and the Presidential Science fellowship funded by the MSIT of the Korean governmentsupport from the Lee-Lucas Chair in Physics,and the Australia Research Council(DP220102152)support from the Australian Research Council(DE220101085 and DP220102152).
文摘The field of high-bandwidth holography has been extensively studied over the past decade.Orbital angular momentum(OAM)holography,which utilizes vortex beams with theoretically unbounded OAM modes as information carriers,showcases the large capacitance of hologram storage.However,OAM holography has been limited to a single wavelength,restricting its potential for full-color holography and displays.In this study,we propose wavelength and OAM multiplexed holography that utilizes the multiple dimensions of light—wavelength and OAM—to provide a multi-color platform that expands the information capacity of holographic storage devices.The proposed wavelength-OAM multiplexed holography is physically realized by a metasurface,the state-of-the-art optical element consisting of an array of artificially engineered nanostructures.Hydrogenated silicon meta-atoms,the constituents of the metasurface,are engineered to possess wavelength selectivity by tailoring the dispersion of polarization conversion.These meta-atoms are used to encode the calculated OAM-preserved phase maps based on our design.The sampling grid of the phase map is rotated by 45°,which effectively suppress higher-order diffraction,providing a great strategy for achieving large field-of-view(FOV)holography.We successfully demonstrate six holographic images that are selectively reconstructed under the illumination of light with specific wavelengths(λ=450,635 nm)and topological charges(l=-2,0,2),without high-order diffraction.Our work suggests that ultrathin meta-holograms can potentially realize ultrahigh-bandwidth full-color holography and holographic video displays with large FOV.
文摘Multiphase flows involving liquid droplets in association with gas flow occur in many industrial and sci- entific applications. Recent work has demonstrated the feasibility of using optical techniques based on laser extinction to simultaneously measure vapor concentration and temperature and droplet size and loading. This work introduces the theoretical background for the optimal design of such laser extinction techniques, termed WMLE （wavelength-multiplexed laser extinction）. This paper focuses on the devel- opment of WMLE and presents a systematic methodology to guide the selection of suitable wavelengths and optimize the performance of WMLE for specific applications. WMLE utilizing wavelengths from 0.5 to 10 ixm is illustrated for droplet size and vapor concentration measurements in an example of water spray, and is found to enable unique and sensitive Sauter mean diameter measurement in the range of ~1-15 ~m along with accurate vapor detection. A vapor detection strategy based on differential absorp- tion is developed to extend accurate measurement to a significantly wider range of droplet loading and vapor concentration as compared to strategies based on direct fixed-wavelength absorption. Expected performance of the sensor is modeled for an evaporating spray. This work is expected to lay the ground- work for implementing optical sensors based on WMLE in a variety of research and industrial applications involving multi-phase flows.
