Quasi-anti-parity–time-symmetric single-resonator micro-optical gyroscope with Kerr nonlinearity

Parity–time(PT) and quasi-anti-parity–time(quasi-APT) symmetric optical gyroscopes have been proposed recently which enhance Sagnac frequency splitting. However, the operation of gyroscopes at the exceptional point(EP) is challenging due to strict fabrication requirements and experimental uncertainties. We propose a new quasi-APT-symmetric micro-optical gyroscope which can be operated at the EP by easily shifting the Kerr nonlinearity. A single resonator is used as the core sensitive component of the quasi-APT-symmetric optical gyroscope to reduce the size, overcome the strict structural requirements and detect small rotation rates. Moreover, the proposed scheme also has an easy readout method for the frequency splitting. As a result, the device achieves a frequency splitting 10~5 times higher than that of a classical resonant optical gyroscope with the Earth's rotation. This proposal paves the way for a new and valuable method for the engineering of micro-optical gyroscopes.

Optical frequency comb significantly spanned to broadband by an optomechanical resonance

An optical frequency comb,as a spectrum made of discrete and equally spaced spectral lines,is a light source with essential applications in modern technology.Cavity optomechanical systems were found to be a feasible candidate for realizing an on-chip frequency comb with low repetition rate.However,it was difficult to increase the comb line numbers of this type of frequency combs because the mechanical oscillation amplitude of such a system,which determines the frequency comb bandwidth,cannot quickly increase with pump laser power.Here,we develop a new approach to generate a broadband optomechanical frequency comb by employing a different mechanism to enhance the mechanical oscillation.Two pump tones with their frequency difference matching the mechanical frequency will drive the system into a self-organized nonlinear resonance and thus tremendously transfer the energy to the mechanical resonator.As a result,more than 10,000 or even more comb lines become available under the pump laser power of the order of milliwatts.A unique feature of the self-organized resonance is the mechanical frequency locking so that,within a certain range of the frequency difference between two drive tones,the distance between comb teeth can be locked by the two drive tones and becomes independent of any change of pump power.This property guarantees a stable repetition rate of the generated frequency comb.

Engineering an enthesis-like graft for rotator cuff repair:An approach to fabricate highly biomimetic scaffold capable of zone-specifically releasing stem cell differentiation inducers

Rotator cuff(RC)attaches to humerus across a triphasic yet continuous tissue zones(bone-fibrocartilage-tendon),termed“enthesis”.Regrettably,rapid and functional enthesis regeneration is challenging after RC tear.The existing grafts bioengineered for RC repair are insufficient,as they were engineered by a scaffold that did not mimic normal enthesis in morphology,composition,and tensile property,meanwhile cannot simultaneously stimulate the formation of bone-fibrocartilage-tendon tissues.Herein,an optimized decellularization approach based on a vacuum aspiration device(VAD)was developed to fabricate a book-shaped decellularized enthesis matrix(O-BDEM).Then,three recombinant growth factors(CBP-GFs)capable of binding collagen were synthesized by fusing a collagen-binding peptide(CBP)into the N-terminal of BMP-2,TGF-β3,or GDF-7,and zone-specifically tethered to the collagen of O-BDEM to fabricate a novel scaffold(CBP-GFs/O-BDEM)satisfying the above-mentioned requirements.After ensuring the low immunogenicity of CBP-GFs/O-BDEM by a novel single-cell mass cytometry in a mouse model,we interleaved urine-derived stem cell-sheets into this CBP-GFs/O-BDEM to bioengineer an enthesis-like graft.Its high-performance on regenerating enthesis was determined in a canine model.These findings indicate this CBP-GFs/O-BDEM may be an excellent scaffold for constructing enthesis-like graft to patch large/massive RC tears,and provide breakthroughs in fabricating graded interfacial tissue.