A novel intermediate connector (IC) was formed which was composed of aluminum (Al, 3 nm)/1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN). The 3-nm-thick Al in the IC is certified to efficiently generate intrinsic charge carriers, and the HAT-CN is proved to work as the holes injection layer (HIL) for the corresponding electroluminescent (EL) unit simultaneously. This simply IC comprehensively takes advantage of the features of the HAT-CN so as to stack two single EL units without introducing extra material. In addition to a significant enhancement in luminance and current efficiency, a current efficiency (CE) of 10.2 cd/A and a luminance of 2 042 cd/m² under the current density 20 mA/cm² of this tandem organic light emitting device (TOLED) are yielded, which are notably almost the sum of that of the two single-unit devices.

In this paper, a novel method is proposed to characterize the operation-waveband angular resolution of the soft X-ray grazing incidence telescope. According to the method, the first is to restore the “geometric image” by removing the aperture diffraction effect from the resolution testing target image measured at visible waveband. The second is to calculate the operation-waveband resolution testing target image by the convolution of “geometric image”, diffraction point spread function and surface scattering point spread function. Finally, the operation-waveband (4.47 nm) angular resolution of 9.72″ is calculated according to the operation-waveband resolution testing target image on axis. The method does not need to be performed in vacuum and to place the source away from the solar X-ray grazing incidence telescope, which greatly reduces the testing cost and improves the efficiency for the development of the soft X-ray grazing incidence telescope.

Accurate time transfer and synchronization between different network nodes is a key functional requirement in digital communication. Developments in optical fiber-based frequency dissemination techniques have improved optical frequency stability over time to much lower levels. In this work, we experimentally present the reference frequency transfer employing 850 nm vertical cavity surface emitting laser (VCSEL) over 100.3 m OM3 multimode fiber for synchronization of clocks on networked devices such as servers and racks/pod at different data center network nodes. A low-cost power-efficient multimode VCSEL with central wavelength at 844.26 nm is directly modulated with a 2 GHz reference frequency (RF) clock signal, and transferred over 100.3 m of OM3 multimode fiber. The single side band (SSB) phase noise of -104.62 dBc/Hz and −100.70 dBc/Hz is experimentally measured at back-to-back (B2B) and 100.3 m OM3 multimode fiber transmission respectively at a 1 kHz frequency offset. The jitter stability of 0.14 ps and 0.15 ps is experimentally achieved at B2B and 100.3 m fiber transmission, respectively. This work provides an alternative viable approach for the development of time keeping devices in high-speed short-reach optical communication systems.

In this work, the perovskite solar cells (PSCs) were fabricated with the bandgap-tunable (FA)_x(MA)_1-xPbI₃ absorber layers through a facile two-stage deposition route. The doping was realized by adding the formamidinium iodide (FAI) into a precursor MAI solution. Both the surface morphology and electrochemical impedance spectra (EIS) were conducted to evaluate the absorber layers or solar cells. After the optimization, the best PSC performance of 14.73% was achieved at a nominal FAI content of 12.5 at.%. The performance enhancement was attributed to both the enhancement of visible light harvesting and carrier transport capability. Besides, the stability of a PSC device based on the single MAPbI3 absorber layer was also investigated, and a power conversion efficiency (PCE) of 11.27% remained even after laying in vacuum for 10 days.

We experimentally compare the solar irradiance absolute radiometer (SIAR) measurement with the world radiometric reference (WRR) standard to improve the accuracy of instrument. The SIAR joined in the international pyrheliometer comparison (IPC) in 2000. The comparison results show that the calibration factors for SIAR to WRR are 0.999 220, 1.001 694, 0.998 334 and 0.997 439 in the 9th IPC, the 10th IPC, the 11th IPC and the 12th IPC, respectively. These results are added to the measurement uncertainty budget of SIAR. The repeatability of the SIAR-type absolute radiometers is also investigated. The relative error introduced by two SIAR-type absolute radiometers is within 0.25%.

We propose a label-free refractive index sensor based on hybrid plasmonic resonator which consists of silver split-ring resonator and photonic waveguide. The finite difference time domain evaluation of the design exhibit strong field confinement at the center of the ring and introduces tunable and sensitive notches in the transmission spectrum. The planar tunable architecture which performs well over the range of micro fluid detection, holds the promise of developing multi-analyte label-free biosensors and compactness towards a complete on-chip integrated sensing system. The performance of the proposed refractive index sensor is evaluated by placing different analytes such as saline water and ethanol at the center of the hybrid plasmonic ring which exhibits sensitivity of 847.50 nm·RIU⁻¹ with a figure of merit of 563.25 RIU⁻¹.

A bandwidth-reconfigurable filter is necessary to meet the need of growing communication capacity and signal coverage frequency range. The stimulated Brillouin scattering (SBS) gain spectrum as a filter passband is used to extract desired microwave signals. Due to the fact that the passband is formed by mapping the Brillouin gain spectrum, bandwidth reconfigurability can be implemented by changing Brillouin gain linewidth. In this paper, a scheme using a 5-lines optical comb acting as a Brillouin pump is experimentally demonstrated. The spectrum of the 5-lines optical comb is extended by a binary phase shift keying (BPSK) pulse modulated signal. Experiments have shown that the 3-dB and 20-dB bandwidths of the filter are 196 MHz and 257 MHz, respectively, and its 20-dB shape factor is 1.31. The passband ripple is ~3.5 dBm with stop-band rejection of 20 dBm under 15 dBm optical pump power.

Epitaxial growths of the GaAs/AlGaAs-based 940 nm infrared light emitting diodes (LEDs) with dual junctions were carried out by using metalorganic chemical vapor deposition (MOCVD) with different doping concentrations and Al contents in Al_xGa_1-x As compound. And their optoelectric properties show that the optimal design for tunneling region corresponds to P⁺⁺ layer with hole concentration up to 1×10²⁰ cm⁻³, N⁺⁺ layer electron concentration up to 5×10¹⁹ cm⁻³ and constituent Al_0.2Ga_0.8As in the tunneling junction region. The optimized dual-junction LED has a forward bias of 2.93 V at an injection current of 50 mA, and its output power is 24.5 mW, which is 104% larger than that of the single junction (12 mW). Furthermore, the optimized device keeps the same spectral characteristics without introducing excessive voltage droop.

Based on the principle of Fabry-Perot (F-P) interference, a new type of optical fiber curvature sensor is presented, which is fabricated by single-mode fiber (SMF), ceramic tube and double-cladding fiber (DCF). And the curvature sensing properties are analyzed, and the double-peak method is used to demodulate the cavity length. The experimental results show that the F-P interference spectrum shifts toward long wavelengths with increasing the curvature. And the sensors are placed in different positions on the cantilever to get their different curvature sensitivities. Smaller initial cavity length gives greater sensor sensitivity. The best curvature sensitivity is achieved as 2 554.53 pm/m^-1 in 0.71—1.18 m^-1. By demodulating the length of the F-P cavity, the cavity length of sensor 4 is changed by 0.08 mm. Therefore, the sensor has some potential for measure the small displacement.

Visual tracking is a challenging problem in computer vision. Recently, correlation filter-based trackers have shown to provide excellent tracking performance. Inspired by a sample consensus approach proposed for foreground detection, which classifies a given pixel as foreground or background based on its similarity to recently observed samples, we present a template consensus tracker based on the kernelized correlation filter (KCF). Instead of keeping only one target appearance model in the KCF, we make a feature pool to keep several target appearance models in our method and predict the new target position by searching for the location of the maximal value of the response maps. Both quantitative and qualitative evaluations are performed on the CVPR2013 tracking benchmark dataset. The results show that our proposed method improves the original KCF tracker by 8.17% in the success plot and 8.11% in the precision plot.