We investigate the phenomenon of coherent perfect absorption in a high-order system with three passive resonators coupled to a super-surface to form this three-state coherent perfect absorber. The effective parity tim...We investigate the phenomenon of coherent perfect absorption in a high-order system with three passive resonators coupled to a super-surface to form this three-state coherent perfect absorber. The effective parity time (PT) symmetry in the passive system has received much attention, and in this open three-state PT symmetric system, the incident wave is used as the effective gain instead of balancing the material gain and loss. We analyze the variation of coherent perfect absorption of this system with the coupling coefficient of the system by simulation.展开更多
In this article,we investigate the phenomenon of coherent perfect absorption(CPA)with bulk Dirac semimetal(BDS)thin film.CPA of BDS appears at the frequency of 43.89 THz with 0°phase modulation of two coherent in...In this article,we investigate the phenomenon of coherent perfect absorption(CPA)with bulk Dirac semimetal(BDS)thin film.CPA of BDS appears at the frequency of 43.89 THz with 0°phase modulation of two coherent input lights.Meanwhile,it shows that CPA can be realized under oblique incidence circumstances for both TM and TE polarizations.Moreover,the frequency of CPA can be adjusted by altering the thickness of BDS thin film,and the dynamic regulation of CPA can be realized by changing the Fermi energy.Finally,the peak coherent absorption frequency can be controlled by changing the degeneracy factor.展开更多
Vision,microscopy,imaging,optical data projection and storage all depend on focusing of light.Dynamic focusing is conventionally achieved with mechanically reconfigurable lenses,spatial light modulators or microfluidi...Vision,microscopy,imaging,optical data projection and storage all depend on focusing of light.Dynamic focusing is conventionally achieved with mechanically reconfigurable lenses,spatial light modulators or microfluidics.Here we demonstrate that dynamic control of focusing can be achieved through coherent interaction of optical waves on a thin beam splitter.We use a nanostructured plasmonic metasurface of subwavelength thickness as the beam splitter,allowing operation in the regimes of coherent absorption and coherent transparency.Focusing of light resulting from illumination of the plasmonic metasurface with a Fresnel zone pattern is controlled by another patterned beam projected on the same metasurface.By altering the control pattern,its phase,or its intensity,we switch the lens function on and off,and alter the focal spot’s depth,diameter and intensity.Switching occurs as fast as the control beam is modulated and therefore tens of gigahertz modulation bandwidth is possible with electro-optical modulators,which is orders of magnitude faster than conventional dynamic focusing technologies.展开更多
In general relativity,a gravitational“white hole”is a hypothetical region of space that cannot be entered from outside.It is the reverse of a“black hole”from which light and information cannot escape.We report an ...In general relativity,a gravitational“white hole”is a hypothetical region of space that cannot be entered from outside.It is the reverse of a“black hole”from which light and information cannot escape.We report an optical device exhibiting intriguing similarities to these objects.It will either totally absorb(optical black hole)or totally reject(optical white hole)light of any wavelength,depending on its polarization.The device’s functionality is based on the formation of a standing wave from the wavefront of spatially coherent incident radiation.Interaction of the standing wave with a thin absorber enables coherent perfect absorption and transmission,whereas polarization sensitivity arises from the geometrical phase of the interfering beams.We provide experimental proof-of-principle demonstrations and show that the device operates as a black and white hole for orthogonal polarizations of the incident light.From a remote point,it will look similar to a gravitational black or white hole depending on the polarization of light.In principle,the optical black and white hole device can operate as a deterministic absorber or rejector throughout the entire electromagnetic spectrum.Broadband absorbers and rejectors can be useful for energy harvesting,detection,stealth technologies,and redistribution of light.展开更多
文摘We investigate the phenomenon of coherent perfect absorption in a high-order system with three passive resonators coupled to a super-surface to form this three-state coherent perfect absorber. The effective parity time (PT) symmetry in the passive system has received much attention, and in this open three-state PT symmetric system, the incident wave is used as the effective gain instead of balancing the material gain and loss. We analyze the variation of coherent perfect absorption of this system with the coupling coefficient of the system by simulation.
基金supported by the National Natural Science Foundation of China(Nos.61875133 and 11874269)the Science and Technology Project of Shenzhen(Nos.JCYJ20190808143801672,JCYJ20190808150803580,JCYJ20180305125036005,JCYJ20180305124842330,and JCYJ20180305125443569)the Natural Science Foundation of Guangdong(No.2018A030313198)。
文摘In this article,we investigate the phenomenon of coherent perfect absorption(CPA)with bulk Dirac semimetal(BDS)thin film.CPA of BDS appears at the frequency of 43.89 THz with 0°phase modulation of two coherent input lights.Meanwhile,it shows that CPA can be realized under oblique incidence circumstances for both TM and TE polarizations.Moreover,the frequency of CPA can be adjusted by altering the thickness of BDS thin film,and the dynamic regulation of CPA can be realized by changing the Fermi energy.Finally,the peak coherent absorption frequency can be controlled by changing the degeneracy factor.
基金supported by the University of Southampton Enterprise Fund,the UK's Engineering and Physical Sciences Research Council(grant EP/M009122/1)the MOE Singapore(grant MOE2011-T3-1-005)。
文摘Vision,microscopy,imaging,optical data projection and storage all depend on focusing of light.Dynamic focusing is conventionally achieved with mechanically reconfigurable lenses,spatial light modulators or microfluidics.Here we demonstrate that dynamic control of focusing can be achieved through coherent interaction of optical waves on a thin beam splitter.We use a nanostructured plasmonic metasurface of subwavelength thickness as the beam splitter,allowing operation in the regimes of coherent absorption and coherent transparency.Focusing of light resulting from illumination of the plasmonic metasurface with a Fresnel zone pattern is controlled by another patterned beam projected on the same metasurface.By altering the control pattern,its phase,or its intensity,we switch the lens function on and off,and alter the focal spot’s depth,diameter and intensity.Switching occurs as fast as the control beam is modulated and therefore tens of gigahertz modulation bandwidth is possible with electro-optical modulators,which is orders of magnitude faster than conventional dynamic focusing technologies.
基金supported by the Zepler Institute Stimulus Fund,UK’s Engineering and Physical Sciences Research Council(Grant Nos.EP/M009122/1 and EP/T02643X/1)the Singapore National Research Foundation(Grant No.NRF2021-QEP2-01-P01).
文摘In general relativity,a gravitational“white hole”is a hypothetical region of space that cannot be entered from outside.It is the reverse of a“black hole”from which light and information cannot escape.We report an optical device exhibiting intriguing similarities to these objects.It will either totally absorb(optical black hole)or totally reject(optical white hole)light of any wavelength,depending on its polarization.The device’s functionality is based on the formation of a standing wave from the wavefront of spatially coherent incident radiation.Interaction of the standing wave with a thin absorber enables coherent perfect absorption and transmission,whereas polarization sensitivity arises from the geometrical phase of the interfering beams.We provide experimental proof-of-principle demonstrations and show that the device operates as a black and white hole for orthogonal polarizations of the incident light.From a remote point,it will look similar to a gravitational black or white hole depending on the polarization of light.In principle,the optical black and white hole device can operate as a deterministic absorber or rejector throughout the entire electromagnetic spectrum.Broadband absorbers and rejectors can be useful for energy harvesting,detection,stealth technologies,and redistribution of light.
