Low loss, wideband, and high extinction ratio TM polarizer based on subwavelength gratings.

We propose a low loss, wideband silicon transverse magnetic (TM) polarizer with high polarization extinction ratio and low reflection based on subwavelength grating. By arranging and optimizing a mutually perpendicular subwavelength grating with different duty cycles as the core and cladding, efficient waveguiding and radiation can be achieved for the TM and transverse electric (TE) injection, respectively. In simulation, the proposed TM polarizer has a footprint of 40µ×16.

Compact plasmon modulator based on the spatial control of carrier density in indium tin oxide.

To keep pace with the demands of semiconductor integration technology, a semiconductor device should offer a small footprint. Here, we demonstrate a compact electro-optic modulator by controlling the spatial distribution of carrier density in indium tin oxide (ITO). The proposed structure is mainly composed of a symmetrical metal electrode layer, calcium fluoride dielectric layer, and an ITO propagating layer.

Tunable bandpass microwave photonic filter with largely reconfigurable bandwidth and steep shape factor based on cascaded silicon nitride micro-ring resonators.

Bandpass microwave photonic filter (MPF) can be achieved based on the well-known phase to intensity conversion method by using phase modulation and single micro-ring resonator (MRR) notch filter. Since MRR could introduce residual phase in handling one optical sideband, the out-of-band radio frequency (RF) rejection ratio and the shape factor of the bandpass MPF are very limited. Here, by introducing another MRR to handle the other optical sideband, the residual phase can be greatly suppressed, thus the filter's performance can be greatly improved.

A multi-parameter tunable plasmon modulator.

Multi-parameter control of light is a key functionality to modulate optical signals in photonic integrated circuits for various applications. However, the traditional optical modulators can only control one or two properties of light at the same time. Herein, we propose a hybrid structure which can modulate the amplitude, wavelength and phase of surface plasmon polaritons (SPPs) simultaneously to overcome these limitations.

Broadly Effective ACE2 Decoy Proteins Protect Mice from Lethal SARS-CoV-2 Infection.

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have been causing increasingly serious drug resistance problem, development of broadly effective and hard-to-escape anti-SARS-CoV-2 agents is an urgent need. Here, we describe further development and characterization of two SARS-CoV-2 receptor decoy proteins, ACE2-Ig-95 and ACE2-Ig-105/106. We found that both proteins had potent and robust neutralization activities against diverse SARS-CoV-2 variants, including BQ.

Frequency-selectable microwave generation based on on-chip switchable spectral shaping and wavelength-to-time mapping.

We propose and experimentally demonstrate a scheme for the photonic generation of pulsed microwave signals with selectable frequency based on spectral shaping and wavelength-to-time mapping (WTTM) technique. The frequency selectivity is realized by channel switching on an integrated silicon-on-insulator (SOI) spectral shaping chip. The incident signal is spectrally shaped by the asymmetric Mach-Zehnder interferometer (MZI) in the selected channel, and an optical spectrum with uniform free spectral range (FSR) can be generated in a broad bandwidth up to dozens of nanometers, implying large microwave signal duration after WTTM if a pulse light source with matched bandwidth is available.

Achieving Fano resonance with an ultra-high slope rate by silicon nitride CROW embedded in a Mach-Zehnder interferometer.

Fano resonance with asymmetric line shape is very promising in many applications such as optical switching, sensing, slow light, laser. Fano resonances based on some integrated structures have been demonstrated on the silicon on insulator platform. However, the extinction ratios and slope rates of the most proposed integrated Fano resonances are relatively low, which limits their applications.

Low loss silicon nitride 1×4 microwave photonic beamforming chip.

In this paper, based on the low loss double strip silicon nitride platform, we designed and fabricated an ultra-low loss 1×4 microwave photonic beamforming chip, which contains a 1×4 beam splitter and four 5-bit optical delay lines. Each optical delay line can achieve 32 delay states varying from 0 ps to about 130 ps, which can support 21 different beamforming angles covers from -56.42° to 56.

Tunable microwave frequency comb generation using a SiN-MDR based actively mode-locked OEO.

Microwave frequency combs (MFCs) have important applications in communication and sensing owing to their characteristics of large number of comb lines, wide frequency range, and high precision of comb spacing. In many applications, MFCs are required to emit signals with tunable center frequency and variable comb spacing to accommodate different operating frequency bands and accuracies. Here, we demonstrate a tunable MFC by injecting a low-frequency electrical signal into a tunable optoelectronic oscillator (OEO).

Compact and broadband silicon mode-order converter using bricked subwavelength gratings.

A compact and broadband silicon mode-order converter (MOC) scheme by employing reciprocal mode evolution between asymmetric input/output taper and bricked subwavelength gratings (BSWG) is proposed. In the proposed MOC, a quasi-TE mode is generated in the BSWG region, which can be regarded as an effective bridge between the two TE modes to be converted. Flexible mode conversion can be realized by only choosing appropriate structure parameters for specific mode transitions between input/output modes and the quasi-TE mode.

Electrical Switching of the Off-Resonance Room-Temperature Valley Polarization in Monolayer MoS by a Double-Resonance Chiral Microstructure.

Enhancing and expanding the manipulated range of room-temperature valley polarization at off-resonance wavelength is extremely crucial to developing various functional valleytronic devices. Although these have been realized through the double-resonance strategy or twist-angle engineering, the demand for electrical control over the concepts remains elusive. Here, we fabricate a gate-tunable double-resonance chiral microstructure using a molybdenum disulfides (MoS) monolayer.

Photonic generation of broadband linearly chirped microwave waveform based on a low-loss silicon on-chip spectral shaper.

A silicon on-chip spectral shaper based on a Sagnac loop incorporating a chirped multi-mode waveguide Bragg grating (WBG) for linearly chirped microwave waveform generation is fabricated and demonstrated. The transmission spectrum of the spectral shaper displays low insertion loss characteristic due to the application of edge coupling taper and multi-mode waveguide based grating. An up-chirped microwave waveform with bandwidth as large as 44 GHz is generated by mapping the spectrum profile of the spectral shaper to the temporal domain through a dispersion fiber.

Parity-time symmetric tunable OEO based on dual-wavelength and cascaded PS-FBGs in a single-loop.

The ability to achieve low phase noise single-mode oscillation within an optoelectronic oscillator (OEO) is of fundamental importance. In the frequency-tunable OEO, the wide microwave photonic filter (MPF) bandwidth is detrimental to select single-mode among the large number of cavity modes, thus leading to low signal quality and spectral purity. Stable single-mode oscillation can be achieved in a large time delay OEO system by harnessing the mechanism from parity-time (PT) symmetry.

Broadband and compact polarization beam splitter in LNOI hetero-anisotropic metamaterials.

In this paper, theoretical modeling and numerical simulations of a high-performance polarization beam splitter (PBS) based on hetero-anisotropic metamaterials are proposed on the lithium-niobate-on-insulator (LNOI) platform. The hetero-anisotropic metamaterials constructed by sub-wavelength gratings (SWGs) can be regarded as effective anisotropy medium, which exhibits strong birefringence without breaking the geometrical symmetry, contributing to the formation of PBS. Rather than the principle of PBS based on beat-length difference of transverse electric (TE) polarization and transverse magnetic (TM) polarization, the device can realize polarization beam splitting in single beat length, and the footprint of the proposed PBS can be reduced to 8 µm × 160 µm (with S-bend).

Tunable asymmetric transmission across stretchable chiral metamaterial.

A stretchable chiral metamaterial with L-shaped and T-shaped Au patterns (SCMM-LT) is proposed to generate asymmetric transmission (AT) for circularly polarized waves on the polydimethylsiloxane substrate in the mid-infrared region. The peak value of AT can reach 50.02% at the resonance wavelength of 19.

The nuclear gene rpl18 regulates erythroid maturation via JAK2-STAT3 signaling in zebrafish model of Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a rare, inherited bone marrow failure syndrome, characterized by red blood cell aplasia, developmental abnormalities, and enhanced risk of malignancy. However, the underlying pathogenesis of DBA is yet to be understood. Recently, mutations in the gene encoding ribosomal protein (RP) L18 were identified in DBA patients.

One-step efficient generation of dual-function conditional knockout and geno-tagging alleles in zebrafish.

CRISPR/Cas systems are widely used to knock out genes by inducing indel mutations, which are prone to genetic compensation. Complex genome modifications such as knockin (KI) might bypass compensation, though difficult to practice due to low efficiency. Moreover, no 'two-in-one' KI strategy combining conditional knockout (CKO) with fluorescent gene-labeling or further allele-labeling has been reported.

Giant enhancement of tunable asymmetric transmission for circularly polarized waves in a double-layer graphene chiral metasurface.

In this letter, we propose a structure based on double-layer graphene-based planar chiral metasurface with a J-shaped pattern to generate asymmetric transmission for circularly polarized waves in the mid-infrared region. Asymmetric transmission of the double-layer structure can reach to 16.64%, which is much larger than that of the monolayer.

Tunable multifunctional reflection polarizer based on a graphene metasurface.

Herein, we present a tunable multifunctional reflection polarizer, based on a graphene metasurface, which is composed of an array of cross double-ellipse graphene patches. A dual band of linear-to-linear (LTL) polarization conversions is achieved due to the superimposition of the two reflection components with a near 0° or 180° phase difference, in the mid-infrared region. By carefully choosing the parameters, linear-to-circular polarization conversion and broadband of LTL polarization conversion (about 0.

Graphene surface plasmon off-axis superlens based on tilted one-dimensional Si/SiO gratings.

Graphene surface plasmon (GSP) superlenses, induced from the negative refraction, have recently been demonstrated in various two-dimensional photonic crystal systems. However, inplane GSP superlenses have never been reported in a one-dimensional (1D) photonic crystal system. Here, we propose a graphene-Si/SiO system, by transferring a graphene sheet on the tilted 1D subwavelength silicon/silica gratings.

Electrochemical detection of glutathione based on Hg(2+)-mediated strand displacement reaction strategy.

Glutathione (GSH) plays an important role in numerous cellular functions, and the abnormal GSH expression is closely related with many dangerous human diseases. In this work, we have proposed a simple but sensitive electrochemical method for quantitative detection of GSH based on an Hg(2+)-mediated strand displacement reaction. Owing to the specific binding of Hg(2+) with T-T mismatches, helper DNA can bind to 3' terminal of probe DNA 1 and initiate the displacement of probe DNA 2 immobilized on an electrode surface.