Since the first observation of parity-time(PT) symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, whi...Since the first observation of parity-time(PT) symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Pérot(FP) resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.展开更多
High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching...High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching.Antimony trisulfide(Sb_(2)S_(3))is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases,which holds the key to color-varying devices.Herein,we proposed a dynamically switchable color printing method using Sb_(2)S_(3)-based stepwise pixelated Fabry-Pérot(FP)cavities with various cavity lengths.The device was fabricated by employing a direct laser patterning that is a less timeconsuming,more approachable,and low-cost technique.As switching the state of Sb_(2)S_(3) between amorphous and crystalline,the multi-color of stepwise pixelated FP cavities can be actively changed.The color variation is due to the profound change in the refractive index of Sb_(2)S_(3) over the visible spectrum during its phase transition.Moreover,we directly fabricated sub-50 nm nano-grating on ultrathin Sb_(2)S_(3) laminate via microsphere 800-nm femtosecond laser irradiation in far field.The minimum feature size can be further decreased down to~45 nm(λ/17)by varying the thickness of Sb_(2)S_(3) film.Ultrafast switchable Sb_(2)S_(3) photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption,camouflaging surfaces,anticounterfeiting,etc.Importantly,our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.展开更多
This paper presents design and simulation of a switchable radiative cooler that exploits phase transition in vanadium di-oxide to turn on and off in response to temperature.The cooler consists of an emitter and a sola...This paper presents design and simulation of a switchable radiative cooler that exploits phase transition in vanadium di-oxide to turn on and off in response to temperature.The cooler consists of an emitter and a solar reflector separated by a spacer.The emitter and the reflector play a role of emitting energy in mid-infrared and blocking incoming solar energy in ultraviolet to near-infrared regime,respectively.Because of the phase transition of doped vanadium dioxide at room tem-perature,the emitter radiates its thermal energy only when the temperature is above the phase transition temperature.The feasibility of cooling is simulated using real outdoor conditions.We confirme that the switchable cooler can keep a desired temperature,despite change in environmental conditions.展开更多
We present a transmission-type polarization conversion metamaterial(PCM)whose functions can be dynamically switched among the linear-to-circular(LTC)and linear-to-linear(LTL)polarization conversions.The proposed PCM c...We present a transmission-type polarization conversion metamaterial(PCM)whose functions can be dynamically switched among the linear-to-circular(LTC)and linear-to-linear(LTL)polarization conversions.The proposed PCM consists of a grating,a polarization conversion surface and a reconfigurable polarization selective surface incorporated with PIN diodes.By changing the states of diodes,the PCM can achieve the reconfigurable manipulations for incident waves.The Fabry-Pérot(F-P)resonances excited by the PCM contribute to the polarization conversions,as is illustrated.Moreover,through establishing the F-P-like cavity model and analyzing the electric field components of the transmitted waves,the conditions for realizing LTC polarization conversion are revealed,which can guide the construction of PCM.The prototype of PCM is fabricated and measured,which can achieve LTC and LTL polarization conversions within 3.31-3.56 GHz and 2.76-4.24 GHz,respectively,the polarization conversion ratios of two functions are higher than 0.95.The measurement results are in agreement with the simulation data.展开更多
We investigate theoretically the carrier transport in a two-dimensional topological insulator of(001)HgTe/CdTe quantum-well heterostructure with inverted band,and find distinct switchable features of the transmission ...We investigate theoretically the carrier transport in a two-dimensional topological insulator of(001)HgTe/CdTe quantum-well heterostructure with inverted band,and find distinct switchable features of the transmission spectra in the topological edge states by designing the double-electric modulation potentials.The transmission spectra exhibit the significant Fabry–Pérot resonances for the double-electric transport system.Furthermore,the transmission properties show rich behaviors when the Fermi energy lies in the different locations in the energy spectrum and the double-electric barrier regions.The opacity and transparency of the double-modulated barrier regions can be controlled by tuning the modulated potentials,Fermi energy and the length of modulated regions.This electrical switching behavior can be realized by tuning the voltages applied on the metal gates.The Fabry–Pérot resonances leads to oscillations in the transmission which can be observed in experimentally.This electric modulated-mechanism provides us a realistic way to switch the transmission in edge states which can be constructed in low-power information processing devices.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674119,11404125,and 11574389)the financial support from the Bird Nest Plan of HUST,Chinasupported by One Hundred-Talent Plan of Chinese Academy of Sciences
文摘Since the first observation of parity-time(PT) symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Pérot(FP) resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.
基金support from the National Key Research and Development Program of China (2020YFA0714504,2019YFA0709100).
文摘High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching.Antimony trisulfide(Sb_(2)S_(3))is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases,which holds the key to color-varying devices.Herein,we proposed a dynamically switchable color printing method using Sb_(2)S_(3)-based stepwise pixelated Fabry-Pérot(FP)cavities with various cavity lengths.The device was fabricated by employing a direct laser patterning that is a less timeconsuming,more approachable,and low-cost technique.As switching the state of Sb_(2)S_(3) between amorphous and crystalline,the multi-color of stepwise pixelated FP cavities can be actively changed.The color variation is due to the profound change in the refractive index of Sb_(2)S_(3) over the visible spectrum during its phase transition.Moreover,we directly fabricated sub-50 nm nano-grating on ultrathin Sb_(2)S_(3) laminate via microsphere 800-nm femtosecond laser irradiation in far field.The minimum feature size can be further decreased down to~45 nm(λ/17)by varying the thickness of Sb_(2)S_(3) film.Ultrafast switchable Sb_(2)S_(3) photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption,camouflaging surfaces,anticounterfeiting,etc.Importantly,our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.
基金financially supported by the Green Science program funded by POSCOthe National Research Foundation(NRF)grants(NRF2019R1A2C3003129,CAMM-2019M3A6B3030637,NRF-2019R1A5A8080290,and NRF-2018M3D1A1058997)funded by the Ministry of Science and ICT,Republic of Korea+2 种基金the Global Ph.D.fellowship(NRF-2017H1A2A1043204)from the Ministry of Education,Republic of Koreathe PIURI fellowship funded by POSTECHa fellowship from Hyundai Motor Chung Mong-Koo Foundation。
文摘This paper presents design and simulation of a switchable radiative cooler that exploits phase transition in vanadium di-oxide to turn on and off in response to temperature.The cooler consists of an emitter and a solar reflector separated by a spacer.The emitter and the reflector play a role of emitting energy in mid-infrared and blocking incoming solar energy in ultraviolet to near-infrared regime,respectively.Because of the phase transition of doped vanadium dioxide at room tem-perature,the emitter radiates its thermal energy only when the temperature is above the phase transition temperature.The feasibility of cooling is simulated using real outdoor conditions.We confirme that the switchable cooler can keep a desired temperature,despite change in environmental conditions.
基金Project supported by the Fundamental Research Funds for Central Universities(Grant No.2682020GF03)
文摘We present a transmission-type polarization conversion metamaterial(PCM)whose functions can be dynamically switched among the linear-to-circular(LTC)and linear-to-linear(LTL)polarization conversions.The proposed PCM consists of a grating,a polarization conversion surface and a reconfigurable polarization selective surface incorporated with PIN diodes.By changing the states of diodes,the PCM can achieve the reconfigurable manipulations for incident waves.The Fabry-Pérot(F-P)resonances excited by the PCM contribute to the polarization conversions,as is illustrated.Moreover,through establishing the F-P-like cavity model and analyzing the electric field components of the transmitted waves,the conditions for realizing LTC polarization conversion are revealed,which can guide the construction of PCM.The prototype of PCM is fabricated and measured,which can achieve LTC and LTL polarization conversions within 3.31-3.56 GHz and 2.76-4.24 GHz,respectively,the polarization conversion ratios of two functions are higher than 0.95.The measurement results are in agreement with the simulation data.
基金Project supported by the College Innovation Project of Guangdong Province(Grant No.2020KTSCX329)the Social Public Welfare and Basic Research Project of Zhongshan City(Grant No.2020B2044)+2 种基金Zhongshan Polytechnic Highlevel Talents Project(Grant No.KYG2102)the National Key R&D Program of China(Grant No.2021YFA1200502)the National Natural Science Foundation of China(Grant No.12174423)。
文摘We investigate theoretically the carrier transport in a two-dimensional topological insulator of(001)HgTe/CdTe quantum-well heterostructure with inverted band,and find distinct switchable features of the transmission spectra in the topological edge states by designing the double-electric modulation potentials.The transmission spectra exhibit the significant Fabry–Pérot resonances for the double-electric transport system.Furthermore,the transmission properties show rich behaviors when the Fermi energy lies in the different locations in the energy spectrum and the double-electric barrier regions.The opacity and transparency of the double-modulated barrier regions can be controlled by tuning the modulated potentials,Fermi energy and the length of modulated regions.This electrical switching behavior can be realized by tuning the voltages applied on the metal gates.The Fabry–Pérot resonances leads to oscillations in the transmission which can be observed in experimentally.This electric modulated-mechanism provides us a realistic way to switch the transmission in edge states which can be constructed in low-power information processing devices.