A Systematic Molecular Dynamics Investigation on the Graphene Polymer Nanocomposites for Bulletproofing

In modern physics and fabrication technology,simulation of projectile and target collision is vital to improve design in some critical applications,like;bulletproofing and medical applications.Graphene,the most prominent member of two dimensional materials presents ultrahigh tensile strength and stiffness.Moreover,polydimethylsiloxane(PDMS)is one of the most important elastomeric materials with a high extensive application area,ranging from medical,fabric,and interface material.In this work we considered graphene/PDMS structures to explore the bullet resistance of resulting nanocomposites.To this aim,extensive molecular dynamic simulations were carried out to identify the penetration of bullet through the graphene and PDMS composite structures.In this paper,we simulate the impact of a diamond bullet with different velocities on the composites made of single-or bi-layer graphene placed in different positions of PDMS polymers.The underlying mechanism concerning how the PDMS improves the resistance of graphene against impact loading is discussed.We discuss that with the same content of graphene,placing the graphene in between the PDMS result in enhanced bullet resistance.This work comparatively examines the enhancement in design of polymer nanocomposites to improve their bulletproofing response and the obtained results may serve as valuable guide for future experimental and theoretical studies.

Advancements in nanofluidics:Unveiling the dynamics of nanoconfined water and its implications for emerging technologies

Over the past two decades,nanofluidics[1]has emerged as a pivotal field with profound implications across various disciplines,including fluid mechanics,condensed matter physics,engineering,materials science,and biomedicine.By confining and manipulating liquids,gases,ions,and other complex fluids at the nanoscale,nanofluidics enables unprecedented control over their behavior and properties.

xtraction of internal phase motions in femtosecond soliton molecules using an orbital-angular-momentum-resolved method

Internal motions in femtosecond soliton molecules provide insight into universal collective dynamics in various nonlinear systems.Here we introduce an orbital-angular-momentum(OAM)-resolved method that maps the relative phase motion within a femtosecond soliton molecule into the rotational movement of the interferometric beam profile of two optical vortices.By this means,long-term relative phase evolutions of doublet and triplet soliton molecules generated in an all-polarization-maintaining mode-locked Er-fiber laser are revealed.This simple and practical OAM-resolved method represents a promising way to directly visualize the complex phase dynamics in a diversity of multisoliton structures.

Feature size below 100 nm realized by UVLEDbased microscope projection photolithography

The demand for miniaturization and integration of optical elements has fostered the development of various micro-and nanofabrication technologies.In this work,we developed a low-cost UV-LED-based microscope projection photolithography system for rapid and high-resolution fabrication.This system can be easily implemented using off-the-shelf components.It allows for micro-and nanostructuring within seconds.By optimizing the process,a minimum feature size down to approximately 85 nm was successfully realized.In addition,investigations on fabrication of the same structures using both costly and economic microscope objectives were performed.Feature sizes below 100 nm can be stably achieved.The demonstrated approach extends the technology capabilities and may find applications in fields such as nanophotonics,biophotonics sensing and material science.

Two-channel, dual-beam-mode, wavelength-tunable femtosecond optical parametric oscillator

Optical vortices,which carry orbital angular momentum,offer special capabilities in a host of applications.A single-laser source with dual-beam-mode output may open up new research fields of nonlinear optics and quantum optics.We demonstrate a dual-channel scheme to generate femtosecond,dualwavelength,and dual-beam-mode tunable signals in the near infrared wavelength range.Dual-wavelength operation is derived by stimulating two adjacent periods of a periodically poled lithium niobate crystal.Pumped by an Yb-doped fiber laser with a Gaussian(lp?0)beam,two tunable signal emissions with different beam modes are observed simultaneously.Although one of the emissions can be tuned from1520 to 1613 nm with the Gaussian(ls?0)beam,the other is capable of producing a vortex spatial profile with different vortex orders(ls?0 to 2)tunable from 1490 to 1549 nm.The proposed system provides unprecedented freedom and will be an exciting platform for super-resolution imaging,nonlinear optics,multidimensional quantum entanglement,etc.

UV-LED projection photolithography for high-resolution functional photonic components

The advancement of micro-and nanostructuring techniques in optics is driven by the demand for continuous miniaturization and the high geometrical accuracy of photonic devices and integrated systems.Here,UV-LED projection photolithography is demonstrated as a simple and low-cost approach for rapid generation of two-dimensional optical micro-and nanostructures with high resolution and accuracy using standard optics only.The developed system enables the projection of structure patterns onto a substrate with 1000-fold demagnification.Photonic devices,e.g.,waveguides and microring resonators,on rigid or flexible substrates with varied geometrical complexity and overall structure dimensions from the nanometer to centimeter scale were successfully prepared.In particular,high-resolution gratings with feature sizes down to 150 nm and periods as small as 400 nm were realized for the first time by this approach.Waveguides made of doped laser active materials were fabricated,and their spontaneous emission was detected.The demonstrated superior performance of the developed approach may find wide applications in photonics,plasmonics,and optical materials science,among others.

Widely tunable,high-power,femtosecond noncollinear optical parametric oscillator in the visible spectral range

Ultrafast visible radiation is of great importance for many applications ranging from spectroscopy to metrology.Because some regions in the visible range are not covered by laser gain media,optical parametric oscillators offer an added value.Besides a high-power broadband laser source,the ability to rapidly tune the frequency of pulses with high-power spectral density offers an extra benefit for experiments such as multicolor spectroscopy or imaging.Here,we demonstrate a broadband,high-power,rapidly tunable femtosecond noncollinear optical parametric oscillator with a signal tuning range of 440–720 nm in the visible range.The oscillator is pumped by the third harmonic of an Yb-fiber laser at 345 nm with a repetition rate of 50.2 MHz.Moreover,the signal wavelength is tuned by changing the cavity length only,and output powers up to 452 m W and pulse durations down to 268 fs are achieved.This is,to the best of our knowledge,the first demonstration of a quickly tunable femtosecond optical parametric oscillator that covers nearly the entire visible spectral range with high output power.