A two⁃port encapsulated low⁃contrast grating with suppressed zeroth order under normal incidence is described in this paper.Based on such grating configuration,the improved efficiency and spectral bandwidth of the fir...A two⁃port encapsulated low⁃contrast grating with suppressed zeroth order under normal incidence is described in this paper.Based on such grating configuration,the improved efficiency and spectral bandwidth of the first order for TE and TM polarizations with a designed period of 1860 nm can be obtained.On the one hand,some of the accurate grating parameters were numerically optimized utilizing a rigorous coupled⁃wave analysis;on the other hand,the inherent physical mechanism suppressing the zeroth order through an encapsulated fused⁃silica grating was adequately interpreted on account of a simplified modal method.Encapsulated grating with a cover layer cannot be simply considered as adding a coating on it.Compared with reported surface⁃relief grating,all parameters of encapsulated grating should be re⁃optimized and the optimized performances of encapsulated grating were greatly improved.Therefore,the encapsulated grating can be potentially applied in writing fiber Bragg gratings.展开更多
The extreme ultraviolet and soft x-ray sources are widely used in various domains. Suppressing higher order harmonics and improving spectral purity are significant. This paper describes a novel method of higher order ...The extreme ultraviolet and soft x-ray sources are widely used in various domains. Suppressing higher order harmonics and improving spectral purity are significant. This paper describes a novel method of higher order harmonics suppression with single order diffraction gratings in extreme ultraviolet and soft x-ray. The principle of harmonic suppression with single order diffraction grating is described, and an extreme ultraviolet and soft x-ray non-harmonics grating monochromator is designed based on the single order diffraction grating. The performance is simulated by an optical design software. The emergent beams of a monochromator with different gratings are measured by a transmission grating spectrometer. The results show that the single order diffraction grating can suppress higher order harmonics effectively, and it is expected to be widely used in synchrotron radiation, diagnostics of laser induced plasma, and astrophysics.展开更多
A single-order diffraction transmission grating named spectroscopic photon sieve(SPS)for soft x-ray region is proposed and demonstrated in this paper.The SPS consists of many circular pinholes located randomly,and can...A single-order diffraction transmission grating named spectroscopic photon sieve(SPS)for soft x-ray region is proposed and demonstrated in this paper.The SPS consists of many circular pinholes located randomly,and can realize both free-standing diffractions and the suppression of higher-order differations.In this paper,the basic concept,numerical simulations,and calibration results of a 1000-lines/mm SPS for soft x-ray synchrotron radiation are presented.As predicted by theoretical calculations,the calibration results of a 1000-lines/mm SPS verify that the higher-order diffractions can be significantly suppressed along the symmetry axis.With the current nanofabrication technique,the SPS can potentially have a higher line density,and can be widely used in synchrotron radiation,laser-induced plasma diagnostics,and astrophysics.展开更多
The acousto-optic modulator(AOM)plays an important role in heterodyne interferometric sensing,and it is always regarded as an ideal optical frequency shifter.In this paper,we compare the effects of its residual zero-o...The acousto-optic modulator(AOM)plays an important role in heterodyne interferometric sensing,and it is always regarded as an ideal optical frequency shifter.In this paper,we compare the effects of its residual zero-order diffraction in different AOM configurations.The theory shows that using double AOMs can effectively solve the same frequency crosstalk problem caused by zero-order perturbation without worsening the noise floor.The interferometer employs a photonics-assisted mmWave composed of two comb lines from an electro-optical frequency comb as the optical source,which results in the laser frequency noise cancellation in the difference.Experimentally,a dither with a peak-to-peak value of 0.15 ps in the single AOM configuration can be effectively suppressed to below the noise floor through double AOMs,which shows the potential to achieve high sensing accuracy.展开更多
The retroreflector based on a gradient metasurface can reflect electromagnetic(EM)waves to the source,and it is small in size and lightweight.However,even if the previous retroreflectors can be used for angle adaptati...The retroreflector based on a gradient metasurface can reflect electromagnetic(EM)waves to the source,and it is small in size and lightweight.However,even if the previous retroreflectors can be used for angle adaptation,the working efficiency declines sharply at large angles.In this paper,a retroreflector is designed based on a reconfigurable origami two-dimensional(2D)metagrating for efficient spin-locked retroreflection and for suppressing unwanted Floquet diffraction channels.After the retroreflection,the handedness of the wave remains consistent with the incident.By changing the folding state of the origami metagrating,the adaptive tangential momentum can be transferred to the incident wave,providing high-performance retroreflection over a continuous incidence angle range of 30°–45.8°(x-direction)and 30°–81°(y-direction).As proof of concept,an electric metagrating-based retroreflector is fabricated in the microwave frequency band,and the simulation and experimental results are consistent.This adaptive origami spin-locked metasurface has promising applications in spin-optics devices,communication systems,remote sensing,and radar cross-section(RCS)enhancement.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51578247).
文摘A two⁃port encapsulated low⁃contrast grating with suppressed zeroth order under normal incidence is described in this paper.Based on such grating configuration,the improved efficiency and spectral bandwidth of the first order for TE and TM polarizations with a designed period of 1860 nm can be obtained.On the one hand,some of the accurate grating parameters were numerically optimized utilizing a rigorous coupled⁃wave analysis;on the other hand,the inherent physical mechanism suppressing the zeroth order through an encapsulated fused⁃silica grating was adequately interpreted on account of a simplified modal method.Encapsulated grating with a cover layer cannot be simply considered as adding a coating on it.Compared with reported surface⁃relief grating,all parameters of encapsulated grating should be re⁃optimized and the optimized performances of encapsulated grating were greatly improved.Therefore,the encapsulated grating can be potentially applied in writing fiber Bragg gratings.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0206004)the National Natural Science Foundation of China(Grant No.11375160)the National Science Instruments Major Project of China(Grant No.2012YQ130125)
文摘The extreme ultraviolet and soft x-ray sources are widely used in various domains. Suppressing higher order harmonics and improving spectral purity are significant. This paper describes a novel method of higher order harmonics suppression with single order diffraction gratings in extreme ultraviolet and soft x-ray. The principle of harmonic suppression with single order diffraction grating is described, and an extreme ultraviolet and soft x-ray non-harmonics grating monochromator is designed based on the single order diffraction grating. The performance is simulated by an optical design software. The emergent beams of a monochromator with different gratings are measured by a transmission grating spectrometer. The results show that the single order diffraction grating can suppress higher order harmonics effectively, and it is expected to be widely used in synchrotron radiation, diagnostics of laser induced plasma, and astrophysics.
基金Project supported by the National Natural Science Foundation for Young Scientists of China(Grant No.11805179).
文摘A single-order diffraction transmission grating named spectroscopic photon sieve(SPS)for soft x-ray region is proposed and demonstrated in this paper.The SPS consists of many circular pinholes located randomly,and can realize both free-standing diffractions and the suppression of higher-order differations.In this paper,the basic concept,numerical simulations,and calibration results of a 1000-lines/mm SPS for soft x-ray synchrotron radiation are presented.As predicted by theoretical calculations,the calibration results of a 1000-lines/mm SPS verify that the higher-order diffractions can be significantly suppressed along the symmetry axis.With the current nanofabrication technique,the SPS can potentially have a higher line density,and can be widely used in synchrotron radiation,laser-induced plasma diagnostics,and astrophysics.
基金supported by the National Natural Science Foundation of China(Nos.62071055 and 62135014)the BUPT Excellent Ph.D.Students Foundation(No.CX2022212)。
文摘The acousto-optic modulator(AOM)plays an important role in heterodyne interferometric sensing,and it is always regarded as an ideal optical frequency shifter.In this paper,we compare the effects of its residual zero-order diffraction in different AOM configurations.The theory shows that using double AOMs can effectively solve the same frequency crosstalk problem caused by zero-order perturbation without worsening the noise floor.The interferometer employs a photonics-assisted mmWave composed of two comb lines from an electro-optical frequency comb as the optical source,which results in the laser frequency noise cancellation in the difference.Experimentally,a dither with a peak-to-peak value of 0.15 ps in the single AOM configuration can be effectively suppressed to below the noise floor through double AOMs,which shows the potential to achieve high sensing accuracy.
基金supported by the National Natural Science Foundation of China(Nos.61971437,61971341,and 61971435)the National Key Research and Development Program of China(No.2022YFB3806200)。
文摘The retroreflector based on a gradient metasurface can reflect electromagnetic(EM)waves to the source,and it is small in size and lightweight.However,even if the previous retroreflectors can be used for angle adaptation,the working efficiency declines sharply at large angles.In this paper,a retroreflector is designed based on a reconfigurable origami two-dimensional(2D)metagrating for efficient spin-locked retroreflection and for suppressing unwanted Floquet diffraction channels.After the retroreflection,the handedness of the wave remains consistent with the incident.By changing the folding state of the origami metagrating,the adaptive tangential momentum can be transferred to the incident wave,providing high-performance retroreflection over a continuous incidence angle range of 30°–45.8°(x-direction)and 30°–81°(y-direction).As proof of concept,an electric metagrating-based retroreflector is fabricated in the microwave frequency band,and the simulation and experimental results are consistent.This adaptive origami spin-locked metasurface has promising applications in spin-optics devices,communication systems,remote sensing,and radar cross-section(RCS)enhancement.
