The cavity ring-down （CRD） technique is adopted for simultaneously measuring s- and p-polarization reflectivity of highly reflective coatings without employing any polarization optics. As the s- and p-polarized ligh...The cavity ring-down （CRD） technique is adopted for simultaneously measuring s- and p-polarization reflectivity of highly reflective coatings without employing any polarization optics. As the s- and p-polarized light trapped in the ring-down cavity decay independently, with a randomly polarized light source the ring-down signal recorded by a photodetector presents a double-exponential waveform consisting of ring-down signals of both s- and p-polarized light. The s- and p-polarization reflectivity values of a test mirror are therefore simultaneously determined by fitting the recorded ring-down signal with a double-exponential function. The determined s- and p-polarization reflectivity of 30° and 45° angle of incidence mirrors are in good agreement with the reflectivity values measured with the conventional CRD technique employing a polarizer for polarization control.展开更多
Photon nanosieves,as amplitude-type metasurfaces,have been demonstrated usually in a transmission mode for optical super-focusing,display,and holography,but the sieves with subwavelength size constrain optical transmi...Photon nanosieves,as amplitude-type metasurfaces,have been demonstrated usually in a transmission mode for optical super-focusing,display,and holography,but the sieves with subwavelength size constrain optical transmission,thus leading to low efficiency.Here,we report reflective photon nanosieves that consist of metallic meta-mirrors sitting on a trans-parent quartz substrate.Upon illumination,these meta-mirrors offer the reflectance of〜50%,which is higher than the transmission of visible light through diameter-identical nanoholes.Benefiting from this configuration,a meta-mirror-based reflective hologram has been demonstrated with good consistence between theoretical and experimental results over the broadband spectrum from 500 nm to 650 nm,meanwhile exhibiting total efficiency of〜7%.Additionally,if an additional high-reflectance layer is employed below these meta-mirrors,the efficiency can be enhanced further for optical anti-counterfeiting.展开更多
Distributed Bragg reflectors (DBRs) are essential components for the development of optoelectronic devices.In this paper, we first report the use of the nanoporous GaN (NP-GaN) DBR as a template for regrowth of InGaN-...Distributed Bragg reflectors (DBRs) are essential components for the development of optoelectronic devices.In this paper, we first report the use of the nanoporous GaN (NP-GaN) DBR as a template for regrowth of InGaN-based light-emitting diodes (LEDs). The wafer-scale NP-GaN DBR, which is fabricated by electrochemical etching in a neutral solution, has a smooth surface, high reflectivity (>99.5%), and wide spectral stop band width (>70 nm). The chemical composition of the regrown LED thin film is similar to that of the reference LED, but the photoluminescence (PL) lifetime, PL intensity, and electroluminescence intensity of the LED with the DBR are enhanced several times compared to those of the reference LED. The intensity enhancement is attributed to the light reflection effect of the NP-GaN DBR and improved crystalline quality as a result of the etching scheme, whereas the enhancement of PL lifetime is attributable to the latter.展开更多
Shaped charge jet formation process is studied under the conditions of different background lights by means of high speed frame photography. In order to shoot true jet appearance, the glass tube in which jet moves is...Shaped charge jet formation process is studied under the conditions of different background lights by means of high speed frame photography. In order to shoot true jet appearance, the glass tube in which jet moves is vacuumized. The experiment results show that observing jet appearance with the double reflecting mirrors system is feasible as long as the vacuum of the glass tube can meet the requirement of experiment.展开更多
文摘The cavity ring-down （CRD） technique is adopted for simultaneously measuring s- and p-polarization reflectivity of highly reflective coatings without employing any polarization optics. As the s- and p-polarized light trapped in the ring-down cavity decay independently, with a randomly polarized light source the ring-down signal recorded by a photodetector presents a double-exponential waveform consisting of ring-down signals of both s- and p-polarized light. The s- and p-polarization reflectivity values of a test mirror are therefore simultaneously determined by fitting the recorded ring-down signal with a double-exponential function. The determined s- and p-polarization reflectivity of 30° and 45° angle of incidence mirrors are in good agreement with the reflectivity values measured with the conventional CRD technique employing a polarizer for polarization control.
基金supported by the National Natural Science Foundation of China (Nos. 12134013 and 61875181)USTC Research Funds of the Double First-Class Initiative (No. YD2030002003)+2 种基金Fundamental Research Funds for the Central Universities in ChinaCAS Poineer Hundred Talents Program the A*STAR IRG grant A2083c0058,CRF grantthe Centre for Micro and Nanoscale Research and Fabrication, University of Science and Technology of China for the support
文摘Photon nanosieves,as amplitude-type metasurfaces,have been demonstrated usually in a transmission mode for optical super-focusing,display,and holography,but the sieves with subwavelength size constrain optical transmission,thus leading to low efficiency.Here,we report reflective photon nanosieves that consist of metallic meta-mirrors sitting on a trans-parent quartz substrate.Upon illumination,these meta-mirrors offer the reflectance of〜50%,which is higher than the transmission of visible light through diameter-identical nanoholes.Benefiting from this configuration,a meta-mirror-based reflective hologram has been demonstrated with good consistence between theoretical and experimental results over the broadband spectrum from 500 nm to 650 nm,meanwhile exhibiting total efficiency of〜7%.Additionally,if an additional high-reflectance layer is employed below these meta-mirrors,the efficiency can be enhanced further for optical anti-counterfeiting.
基金National Natural Science Foundation of China (NSFC) (61376069,11775134)Key Research and Development Plan of Shandong Province,China (2018GGX102024,2018GGX102014)
文摘Distributed Bragg reflectors (DBRs) are essential components for the development of optoelectronic devices.In this paper, we first report the use of the nanoporous GaN (NP-GaN) DBR as a template for regrowth of InGaN-based light-emitting diodes (LEDs). The wafer-scale NP-GaN DBR, which is fabricated by electrochemical etching in a neutral solution, has a smooth surface, high reflectivity (>99.5%), and wide spectral stop band width (>70 nm). The chemical composition of the regrown LED thin film is similar to that of the reference LED, but the photoluminescence (PL) lifetime, PL intensity, and electroluminescence intensity of the LED with the DBR are enhanced several times compared to those of the reference LED. The intensity enhancement is attributed to the light reflection effect of the NP-GaN DBR and improved crystalline quality as a result of the etching scheme, whereas the enhancement of PL lifetime is attributable to the latter.
文摘Shaped charge jet formation process is studied under the conditions of different background lights by means of high speed frame photography. In order to shoot true jet appearance, the glass tube in which jet moves is vacuumized. The experiment results show that observing jet appearance with the double reflecting mirrors system is feasible as long as the vacuum of the glass tube can meet the requirement of experiment.
