Multifunctional mixed analog/digital signal processor based on integrated photonics

Photonic signal processing offers a versatile and promising toolkit for contemporary scenarios ranging from digital optical communication to analog microwave operation.Compared to its electronic counterpart,it eliminates inherent bandwidth limitations and meanwhile exhibits the potential to provide unparalleled scalability and flexibility,particularly through integrated photonics.However,by far the on-chip solutions for optical signal processing are often tailored to specific tasks,which lacks versatility across diverse applications.Here,we propose a streamlined chip-level signal processing architecture that integrates different active and passive building blocks in silicon-on-insulator(SOI)platform with a compact and efficient manner.Comprehensive and in-depth analyses for the architecture are conducted at levels of device,system,and application.Accompanied by appropriate configuring schemes,the photonic circuitry supports loading and processing both analog and digital signals simultaneously.Three distinct tasks are facilitated with one single chip across several mainstream fields,spanning optical computing,microwave photonics,and optical communications.Notably,it has demonstrated competitive performance in functions like image processing,spectrum filtering,and electro-optical bandwidth equalization.Boasting high universality and a compact form factor,the proposed architecture is poised to be instrumental for next-generation functional fusion systems.

Pd-catalyzed intermolecular Si–O formation via Si–C activation

The development of efficient Si–O bond formation reaction with 100% atom-economy, excellent functional group tolerance, and broad scope under mild conditions is highly desired due to the prevalence of silanol, silyl ether, and their derivatives in synthetic chemistry and materials science. Here, we have realized the Pd-catalyzed Si–O formation reaction via a Si–C activation approach with 100% atom-economy by employing silacyclobutanes(SCBs) and various hydroxy-containing substrates, including water,alcohols, phenols, and silanols. This protocol features a broad substrate scope, remarkable functional compatibility and mild conditions, providing a series of silanols, silyl ethers in high efficiency. Notably, this protocol could also be used for selective protection of hydroxy functionalities, and for the access of a class of novel polymers containing Si–O main chain. Preliminary mechanistic studies unveiled that this reaction underwent a Pd-catalyzed concerted ring-opening mechanism.

Versatile photonic molecule switch in multimode microresonators

Harnessing optical supermode interaction to construct artificial photonic molecules has uncovered a series of fundamental optical phenomena analogous to atomic physics.Previously,the distinct energy levels and interactions in such two-level systems were provided by coupled microresonators.The reconfigurability is limited,as they often require delicate external field stimuli or mechanically altering the geometric factors.These highly specific approaches also limit potential applications.Here,we propose a versatile on-chip photonic molecule in a multimode microring,utilizing a flexible regulation methodology to dynamically control the existence and interaction strength of spatial modes.The transition between single/multi-mode states enables the“switched-off/on”functionality of the photonic molecule,supporting wider generalized applications scenarios.In particular,“switched-on”state shows flexible and multidimensional mode splitting control in aspects of both coupling strength and phase difference,equivalent to the a.c.and d.c.Stark effect.“Switched-off”state allows for perfect low-loss single-mode transition(Qi~10 million)under an ultra-compact bend size(FSR~115 GHz)in a foundry-based silicon microring.It breaks the stereotyped image of the FSR-Q factor trade-off,enabling ultra-wideband and high-resolution millimeter-wave photonic operations.Our demonstration provides a flexible and portable solution for the integrated photonic molecule system,extending its research scope from fundamental physics to real-world applications such as nonlinear optical signal processing and sixth-generation wireless communication.

Highly reconfigurable silicon integrated microwave photonic filter towards next-generation wireless communication

Integrated microwave photonic filters(IMPFs)are capable of offering unparalleled performances in terms of superb spectral fineness,broadband,and more importantly,the reconfigurability,which encounter the trend of the next-generation wireless communication.However,to achieve high reconfigurability,previous works should adopt complicated system structures and modulation formats,which put great pressure on power consumption and controlment,and,therefore,impede the massive deployment of IMPF.Here,we propose a streamlined architecture for a wideband and highly reconfigurable IMPF on the silicon photonics platform.For various practical filter responses,to avoid complex auxiliary devices and bias drift problems,a phase-modulated flexible sideband cancellation method is employed based on the intensity-consistent single-stage-adjustable cascadedmicroring(ICSSA-CM).The IMPF exhibits an operation band extending to millimeter-wave(≥30 GHz),and other extraordinary performances including high spectral resolution of 220 MHz and large rejection ratio of 60 d B are obtained.Moreover,Gb/s-level RF wireless communications are demonstrated for the first time towards real-world scenarios.The proposed IMPF provides broadband flexible spectrum control capabilities,showing great potential in the next-generation wireless communication.

Thianthrene Radical Cation as a Transient SET Mediator:Photoinduced Thiocyanation and Selenocyanation of Arylthianthrenium Salts

Comprehensive Summary A novel transient SET mediator approach has been developed for the photoinduced radical-radical cross coupling reaction.Using the in-situ generated thianthrene radical cation as the transient SET mediator,the thiocyanation and selenocyanation of aryl thianthrenium salts have been realized under the mild conditions without the need for photocatalyst or single electron donor.In comparison with the photocatalyst enabled process,the protocol features mild conditions,simple manipulation,a broad substrate scope,excellent functional group and heterocycle tolerance.Due to the feasible accessibility of aryl thianthrenium salts,this method has also been applied in the efficient synthesis of a bioactive molecule,and the late-stage functionalization of complex arenes.

Adult tiger beetles Cicindela gemmata modify their foraging strategy in different hunting contexts

Predator–prey interaction has long been an interesting item in the research of animal behaviors.Given that live prey can damage their predators,predators must trade foraging efficiency for safety while hunting,but the extent of this trade-off is not yet clear.Tiger beetles display diversity in their diets and hunting strategies,and hence,they become an ideal system to address how self-security affects foraging efficiency.We addressed this question in captive adult tiger beetles Cicindela gemmata.By offering several types of arthropod and plant foods,we confirmed that C.gemmata is carnivorous.We found that C.gemmata hunt by either ambushing or chasing their prey,and that they switch between strategies based on differences in the number of prey,the prey status and encounter rate,and the number of predators.Ambushing success increased with the number of prey but decreased with prey encounter rate.Chasing success decreased as prey body size and encounter rate increased.Foraging Cicindela gemmata often gave up an attack when it was nonfatal.This active giving up of hunting may be a consequence of a trade-off between foraging efficiency and self-security.Therefore,it is an adaptive response to the risk of injury when hunting for larger live prey.

Genetic Approaches for Sex Determination of Chinese Female with Male Pseudohermaphroditism

Male pseudohermaphroditism is a rare disorders of sex development(DSD)that is manifested by a female-like appearance or incompletely differentiated external genitalia in an individual with a Y chromosome.In this paper,we report our investigation of the case of a 33-year-old Chinese female who was diagnosed with a malignant mixed germ-cell tumor of the ovary.To confirm the sex of the female,we utilized genetic approaches to detect amelogenin and Y-STR loci.Y chromosome microdeletion was performed to identify existing deletions in the AZF regions and SRY.Chromosome karyotyping and whole-exome sequencing(WES)were then applied to reveal the deletion of sex chromosome segments and pathogenic variations in DNA sequences.Using DNA-STR genotyping,we detected both AMEL-X and AMEL-Y fragments.We also found haplotype Y-STR loci and detected all alleles.Furthermore,no microdeletion was detected in the AZF regions and SRY.The chromosome karyotyping was 46,XY.WES revealed a transversion mutation of 58T→C in the androgen receptor exon 1,which could be the pathogenic variant in this case of abnormal sexual development.Sex determination in forensic DNA typing is based on the amelogenin system.It is important that forensic biologists should master various genetic approaches to overcome the issue of gender ambiguity caused by DSDs.

Deep learning in holography and coherent imaging

Recent advances in deep learning have given rise to a new paradigm of holographic image reconstruction and phase recovery techniques with real-time performance.Through data-driven approaches,these emerging techniques have overcome some of the challenges associated with existing holographic image reconstruction methods while also minimizing the hardware requirements of holography.These recent advances open up a myriad of new opportunities for the use of coherent imaging systems in biomedical and engineering research and related applications.

A deep learning-enabled portable imaging flow cytometer for cost-effective, highthroughput, and label-free analysis of natural water samples

We report a deep learning-enabled field-portable and cost-effective imaging flow cytometer that automatically captures phase-contrast color images of the contents of a continuously flowing water sample at a throughput of 100 mL/h.The device is based on partially coherent lens-free holographic microscopy and acquires the diffraction patterns of flowing micro-objects inside a microfluidic channel.These holographic diffraction patterns are reconstructed in real time using a deep learning-based phase-recovery and image-reconstruction method to produce a color image of each micro-object without the use of external labeling.Motion blur is eliminated by simultaneously illuminating the sample with red,green,and blue light-emitting diodes that are pulsed.Operated by a laptop computer,this portable device measures 15.5 cm×15 cm×12.5 cm,weighs 1 kg,and compared to standard imaging flow cytometers,it provides extreme reductions of cost,size and weight while also providing a high volumetric throughput over a large object size range.We demonstrated the capabilities of this device by measuring ocean samples at the Los Angeles coastline and obtaining images of its micro-and nanoplankton composition.Furthermore,we measured the concentration of a potentially toxic alga(Pseudo-nitzschia)in six public beaches in Los Angeles and achieved good agreement with measurements conducted by the California Department of Public Health.The cost-effectiveness,compactness,and simplicity of this computational platform might lead to the creation of a network of imaging flow cytometers for largescale and continuous monitoring of the ocean microbiome,including its plankton composition.

Bright-field holography:cross-modality deep learning enables snapshot 3D imaging with bright-field contrast using a single hologram

Digital holographic microscopy enables the 3D reconstruction of volumetric samples from a single-snapshot hologram.However,unlike a conventional bright-field microscopy image,the quality of holographic reconstructions is compromised by interference fringes as a result of twin images and out-of-plane objects.Here,we demonstrate that cross-modality deep learning using a generative adversarial network(GAN)can endow holographic images of a sample volume with bright-field microscopy contrast,combining the volumetric imaging capability of holography with the speckle-and artifact-free image contrast of incoherent bright-field microscopy.We illustrate the performance of this“bright-field holography”method through the snapshot imaging of bioaerosols distributed in 3D,matching the artifact-free image contrast and axial sectioning performance of a high-NA bright-field microscope.This data-driven deep-learning-based imaging method bridges the contrast gap between coherent and incoherent imaging,and enables the snapshot 3D imaging of objects with bright-field contrast from a single hologram,benefiting from the wave-propagation framework of holography.

Para-selective borylation of monosubstituted benzenes using a transient mediator

Herein,we conceptualized a transient mediator approach that has the capability of para-selective C–H functionalization of monosubstituted aromatics.This approach is enabled by in situ generation of a versatile sulfonium salt via highly electrophilic phenoxathiine or thianthrene dication intermediate which can be readily generated from its sulfoxide with trifluoromethanesulfonic anhydride.Preliminary mechanistic study implied that the remarkable para selectivity might be related to the incredible electrophilicity of thianthrene dication intermediate.The versatility of this approach was demonstrated via paraborylation of various monosubstituted simple aromatics combining the sulfonium salt formation with further photocatalyzed transformation.