We propose a kind of spectral polarization-encoding(SPE)for broadband light pulses,which is realized by inducing optical rotatory dispersion(ORD),and decoded by compensating ORD.Combining with polarization-sensitive d...We propose a kind of spectral polarization-encoding(SPE)for broadband light pulses,which is realized by inducing optical rotatory dispersion(ORD),and decoded by compensating ORD.Combining with polarization-sensitive devices,SPE can not only work to control polarization-dependent transmission for central wavelength or bandwidth-tunable filtering,but also can be used for broadband regenerative or multi-pass amplification with a polarization-dependent gain medium to improve output bandwidth.SPE is entirely passive thus very simple to be designed and aligned.By using an ORD crystal with a good transmission beyond 3-μm mid-infrared region,e.g.,Ag Ga S_(2),SPE promises to be applied for the wavelength tuning lasers in mid-infrared region,where the tunning devices are rather under developed compared with those in visible and near-infrared region.展开更多
Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbi...Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum(OAM).Here we have reviewed the ways to generate THz vortex beams by two representative scenarios,i.e.,THz wavefront modulation via specific devices,and direct excitation of the helicity of THz vortex beams.The former is similar to those wavefront engineering devices in the optical and infrared(IR)domain,but just with suitable THz materials,while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though,which would provide both challenges and opportunities for THz vortex beam generation.As for their applications,thanks to the recent development of THz optics and singular optics,THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields.Besides,some representative potential applications are evaluated such as THz wireless communication,THz super-resolution imaging,manipulating chiral matters,accelerating electron bunches,and detecting astrophysical sources.展开更多
A new type and easy-to-fabricate metal-insulator-metal(MIM) waveguide reflector based on Sagnac loop is designed and investigated.The transfer matrix theoretical model for the transmission of electric fields in the re...A new type and easy-to-fabricate metal-insulator-metal(MIM) waveguide reflector based on Sagnac loop is designed and investigated.The transfer matrix theoretical model for the transmission of electric fields in the reflector is established,and the properties of the reflector are studied and analyzed.The simulation results indicate that the reflectivity strongly depends on the coupling splitting ratio determined by the coupling length.Accordingly, different reflectivities can be realized by varying the coupling length.For an optimum coupling length of 750 nm, the 3-dB reflection bandwidth of the MIM waveguide reflector is as wide as 1.5 μm at a wavelength of 1550 nm, and the peak reflectivity and isolation are 78%and 23 dB, respectively.展开更多
Applying an ultrafast vortex laser as the pump,optical parametric amplification can be used for spiral phase-contrast imaging with high gain,wide spatial bandwidth,and high imaging contrast.Our experiments show that t...Applying an ultrafast vortex laser as the pump,optical parametric amplification can be used for spiral phase-contrast imaging with high gain,wide spatial bandwidth,and high imaging contrast.Our experiments show that this design has realized the 1064 nm spiral phase-contrast idler imaging of biological tissues(frog egg cells and onion epidermis)with a spatial resolution at several microns level and a superior imaging contrast to both the traditional bright-or dark-field imaging under a weak illumination of 7 nW/cm^(2).This work provides a powerful way for biological tissue imaging in the second near-infrared region.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 60477042, and Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology.
基金the National Natural Science Foundation of China(Grant Nos.92050203,62075138,61827815,and 61775142)Shenzhen Fundamental Research Project(Grant Nos.JCYJ20190808164007485,JCYJ20190808121817100,JSGG20191231144201722,and JCYJ20190808115601653)。
文摘We propose a kind of spectral polarization-encoding(SPE)for broadband light pulses,which is realized by inducing optical rotatory dispersion(ORD),and decoded by compensating ORD.Combining with polarization-sensitive devices,SPE can not only work to control polarization-dependent transmission for central wavelength or bandwidth-tunable filtering,but also can be used for broadband regenerative or multi-pass amplification with a polarization-dependent gain medium to improve output bandwidth.SPE is entirely passive thus very simple to be designed and aligned.By using an ORD crystal with a good transmission beyond 3-μm mid-infrared region,e.g.,Ag Ga S_(2),SPE promises to be applied for the wavelength tuning lasers in mid-infrared region,where the tunning devices are rather under developed compared with those in visible and near-infrared region.
基金Project supported partly by the National Natural Science Foundation of China(Grant Nos.61775142 and 61705132)Shenzhen Fundamental Research and Discipline Layout Project,China(Grant Nos.JCYJ20170412105812811,JCYJ20190808164007485,JCYJ20190808121817100,and JCYJ20190808115601653).
文摘Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum(OAM).Here we have reviewed the ways to generate THz vortex beams by two representative scenarios,i.e.,THz wavefront modulation via specific devices,and direct excitation of the helicity of THz vortex beams.The former is similar to those wavefront engineering devices in the optical and infrared(IR)domain,but just with suitable THz materials,while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though,which would provide both challenges and opportunities for THz vortex beam generation.As for their applications,thanks to the recent development of THz optics and singular optics,THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields.Besides,some representative potential applications are evaluated such as THz wireless communication,THz super-resolution imaging,manipulating chiral matters,accelerating electron bunches,and detecting astrophysical sources.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61827815 and 61775142)
文摘A new type and easy-to-fabricate metal-insulator-metal(MIM) waveguide reflector based on Sagnac loop is designed and investigated.The transfer matrix theoretical model for the transmission of electric fields in the reflector is established,and the properties of the reflector are studied and analyzed.The simulation results indicate that the reflectivity strongly depends on the coupling splitting ratio determined by the coupling length.Accordingly, different reflectivities can be realized by varying the coupling length.For an optimum coupling length of 750 nm, the 3-dB reflection bandwidth of the MIM waveguide reflector is as wide as 1.5 μm at a wavelength of 1550 nm, and the peak reflectivity and isolation are 78%and 23 dB, respectively.
基金partially supported by the National Natural Science Foundation of China(Nos.92050203,62075138,12174264,61827815,12004261,and 61775142)Natural Science Foundation of Guangdong Province(Nos.2021A1515011909 and 2022A1515011457)+1 种基金Shenzhen Fundamental Research Program(Nos.JCYJ20200109105606426,JCYJ20190808164007485,JCYJ20210324095213037,JCYJ20190808121817100,JCYJ20190808143419622,and JCYJ20190808115601653)Shenzhen Key Technology Projects(Nos.JSGG20191231144201722 and JSGG20211108092800001).
文摘Applying an ultrafast vortex laser as the pump,optical parametric amplification can be used for spiral phase-contrast imaging with high gain,wide spatial bandwidth,and high imaging contrast.Our experiments show that this design has realized the 1064 nm spiral phase-contrast idler imaging of biological tissues(frog egg cells and onion epidermis)with a spatial resolution at several microns level and a superior imaging contrast to both the traditional bright-or dark-field imaging under a weak illumination of 7 nW/cm^(2).This work provides a powerful way for biological tissue imaging in the second near-infrared region.
