The traditional remote sensing mainly detects the ground vertically to obtain the 2D information but it is hard to get adequate parameters for the quantitative remote sensing to invert land features. The multi-angle o...The traditional remote sensing mainly detects the ground vertically to obtain the 2D information but it is hard to get adequate parameters for the quantitative remote sensing to invert land features. The multi-angle observation can get more detailed and reliable 3D structural parameters of targets, so it makes the quantitative remote sensing applicable. During the process of reflecting, scattering and transmitting the electromagnetic wave, minerals and rocks could reveal the polarized features related to the nature of themselves. Therefore, it has become a new approach of quantitative remote sensing to detect multi-angle polarized information of minerals and rocks. In respect that the polarized reflectance always goes with the bidirectional one, we can obtain the 3D spatial distribution of targets by a polarized means together with detecting its bi-directional reflectance. From the perspective of multi-angle polarized remote sensing mechanism, the quantitative relationship between multi-angle polarized reflectance and the BRDF is studied in this paper. And it is testified that the bi-directional reflectance, polarized reflectance of 45° and the mean value of polarized reflectance are equal to that of the corresponding azimuth angle, zenith angle, detection angle and detection channels in 27t space by experiment.展开更多
An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflec...An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately.展开更多
A high-contrast grating（HCG） focusing reflector providing phase front control of reflected light and high reflectivity is proposed and fabricated.Basic design rules to engineer this category of structures are given ...A high-contrast grating（HCG） focusing reflector providing phase front control of reflected light and high reflectivity is proposed and fabricated.Basic design rules to engineer this category of structures are given in detail.A 1550 nm TM polarized incident light of 11.86 mm in focal length and 0.8320 in reflectivity is obtained in experiment.The wavelength dependence of the fabricated HCGs from 1530 nm to 1580 nm is also tested.The test results show that the focal length is in the range of 11.81-12 mm,which is close to the designed focal length of 15 mm.The reflectivity is almost above 0.56 within a bandwidth of 50 nm.At a distance of 11.86 mm,the light is focused to a round spot with the highest concentration,which is much smaller than the size of the incident beam.The FWHM of the reflected light beam decreases to 120 nm,and the intensity increases to 1.18.展开更多
We theoretically study the differential conductance of a graphene/graphene superconductor junction, where the valley polarization of Dirac electrons is considered in the nonsuperconducting region. It is shown that the...We theoretically study the differential conductance of a graphene/graphene superconductor junction, where the valley polarization of Dirac electrons is considered in the nonsuperconducting region. It is shown that the subgap conductance will increase monotonically with the valley-polarization strength when the chemical potential μ is near the Dirac point μ≤ 3？（？ is the superconducting gap）, whereas it will decrease monotonically when μ is far away from the Dirac point, μ≥ 5？.The former case is induced by the specular Andreev reflection while the retro-reflection accounts for the later result. Our findings may shed light on the control of conductance of a graphene superconductor junction by valley polarization.展开更多
基金Project KZCX3-S W-338-1 supported by Science and Technology Innovation Foundation of Chinese Academy of Science and 49771057 supported by theNational Natural Science Foundation of China
文摘The traditional remote sensing mainly detects the ground vertically to obtain the 2D information but it is hard to get adequate parameters for the quantitative remote sensing to invert land features. The multi-angle observation can get more detailed and reliable 3D structural parameters of targets, so it makes the quantitative remote sensing applicable. During the process of reflecting, scattering and transmitting the electromagnetic wave, minerals and rocks could reveal the polarized features related to the nature of themselves. Therefore, it has become a new approach of quantitative remote sensing to detect multi-angle polarized information of minerals and rocks. In respect that the polarized reflectance always goes with the bidirectional one, we can obtain the 3D spatial distribution of targets by a polarized means together with detecting its bi-directional reflectance. From the perspective of multi-angle polarized remote sensing mechanism, the quantitative relationship between multi-angle polarized reflectance and the BRDF is studied in this paper. And it is testified that the bi-directional reflectance, polarized reflectance of 45° and the mean value of polarized reflectance are equal to that of the corresponding azimuth angle, zenith angle, detection angle and detection channels in 27t space by experiment.
文摘An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61274044,61574019 and 61020106007)the National Basic Research Program of China(Grant No.2010CB327600)+4 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20130005130001)the Natural Science Foundation of Beijing,China(Grant No.4132069)the Key International Science and Technology Cooperation Project of China(Grant No.2011RR000100)the 111 Project of China(Grant No.B07005)the Program for Changjiang Scholars and Innovative Research Team in Universities of China(Grant No.IRT0609)
文摘A high-contrast grating（HCG） focusing reflector providing phase front control of reflected light and high reflectivity is proposed and fabricated.Basic design rules to engineer this category of structures are given in detail.A 1550 nm TM polarized incident light of 11.86 mm in focal length and 0.8320 in reflectivity is obtained in experiment.The wavelength dependence of the fabricated HCGs from 1530 nm to 1580 nm is also tested.The test results show that the focal length is in the range of 11.81-12 mm,which is close to the designed focal length of 15 mm.The reflectivity is almost above 0.56 within a bandwidth of 50 nm.At a distance of 11.86 mm,the light is focused to a round spot with the highest concentration,which is much smaller than the size of the incident beam.The FWHM of the reflected light beam decreases to 120 nm,and the intensity increases to 1.18.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274059 and 11074233)
文摘We theoretically study the differential conductance of a graphene/graphene superconductor junction, where the valley polarization of Dirac electrons is considered in the nonsuperconducting region. It is shown that the subgap conductance will increase monotonically with the valley-polarization strength when the chemical potential μ is near the Dirac point μ≤ 3？（？ is the superconducting gap）, whereas it will decrease monotonically when μ is far away from the Dirac point, μ≥ 5？.The former case is induced by the specular Andreev reflection while the retro-reflection accounts for the later result. Our findings may shed light on the control of conductance of a graphene superconductor junction by valley polarization.
