Metal−Organic Framework-Based Ultrafast Logic Gates for High-Security Optical Encryption

Optical logic gates call for materials with giant optical nonlinearity to break the current performance bottleneck.Metal–organic frameworks(MOFs)provide an intriguing route to achieve superior optical nonlinearity benefitting from structural diversity and design flexibility.However,the potential of MOFs for optoelectronics has been largely overlooked and their applications in optical logic have not been exploited.Here,through temporally manipulating the nonlinear optical absorption process in porphyrin-based MOFs,we have successfully developed AND and XOR logic gates with an ultrafast speed approaching 1 THz and an on–off ratio above 90%.On this basis,all-optical information encryption is further demonstrated using transmittance as primary codes,which shows vast prospects in avoiding the disclosure of security information.To the best of our knowledge,this is the first exploration of MOFs for applications in ultrafast optical logic devices and information encryption.

Impacts of inter-satellite links on the ECOM model performance for BDS-3 MEO satellites

Inter-satellite link(ISL)plays an essential role in current and future Global Navigation Satellite System(GNSS).In this study,we investigate the impact of ISL observations on precise orbit determination for BeiDou-3 Navigation Satellite System(BDS-3)Medium Earth Orbit(MEO)satellites based on different Extended CODE Orbit Models(ECOM).Thanks to the better observation geometry of the Ka-band ISL data compared to the L-band data for BDS-3 MEO satellites,the ISL solution substantially reduces Orbit Boundary Discontinuity(OBD)errors,except for C30,which suffers from unstable Ka-band hardware delay.From the external quality analysis,ISL significantly enhances the reliability of the orbit of MEO satellites manufactured by the China Academy of Space Technology(CAST).The standard deviation(STD)of the satellite laser ranging(SLR)residuals is approximately 2.5 cm,and the root mean square(RMS)is reduced by 10–23%compared to L-band solutions.Besides,the Sun-elongation angle dependent systematic error in SLR residuals nearly vanishes based on the reduced 5-parameter ECOM(ECOM1)or extended 7-parameter ECOM(ECOM2)with ISL data.This is because the ISL reduces the correlation between state parameters and solar radiation pressure(SRP)parameters as well as those among SRP parameters,leading to a more accurate estimation of both orbit and SRP perturbations,particularly those along B direction.This confirms that the deficiency of the SRP models for BDS-3 CAST satellites can be compensated by using better observation geometry from ISL data.On the other hand,for the satellite manufactured by Shanghai Engineering Center for Microsatellites(SECM),the ISL allows for a more accurate estimation of the Bc_(1)parameter in the ECOM1 model.This only reduces linear systematic error,possibly because the impact generated by the satellite bus cannot be entirely absorbed by the B-direction parameters.