Propagation Properties Of Beams Research Articles

Propagation properties of the electron circular vortex beam based on the butterfly catastrophe

Propagation properties of the electron circular vortex beam based on the butterfly catastrophe

Propagation properties of general model vortex higher-order Cosh-Gaussian laser beam through uniaxial crystal orthogonal to the optical axis

Propagation properties of general model vortex higher-order Cosh-Gaussian laser beam through uniaxial crystal orthogonal to the optical axis

Generation and propagation properties of Bessel-Gaussian beams with a rotationally symmetric power-exponent-phase vortex.

In this paper, the generation and propagation properties of Bessel-Gaussian (BG) rotationally symmetric power-exponent-phase vortex beam (RSPEPVBs) were demonstrated and discussed. The results showed that the BG-RSPEPVBs can be directly generated based on the spatial light modulator, of which the phase singularities were verified by the interference patterns with the plane wave. It can be found that the intensity distributions of the BG-RSPEPVBs, with different topological charges (TCs) and power orders, were fan-shaped and polycyclic, which possessed the characteristics of BG beams and RSPEPVBs, simultaneously. Thus, the propagation invariance of the BG-RSPEPVBs is better than that of Laguerre-Gaussian RSPEPVBs and RSPEPVBs. Moreover, the focusing spot of the BG-RSPEPVBs would evolve into a bright ring with the same ring radius at the focal plane, which is independent of the TC and more suitable for the applications of optical coupling, optical communication, optical trapping, and so on.

The Propagation Characteristics of Circular Airy Beams with Propagational Fractional-Order Optical Vortices

We investigate the propagation properties of circular Airy beams (CABs) with propagational fractional-order optical vortices (OVs). The superposition of the phase singularity and polarization singularity from a vortex vector beam (VVB) plays a significant role in creating a propagational fractional vortex beam. Propagational fractional vortex beams can be considered as a superposition of left and right circularly polarized vortex beams with different integer topological charges (TCs). We study the propagation characteristics of two kinds of propagational fractional vortex CABs, and the results show that both of the two kinds of beams can stably propagate in free space, and they exhibit an “abruptly auto-focusing” property and “self-healing” property during the propagation. The intensity distribution of the first kind of propagational fractional vortex CAB has an odd number of petals (2m + 1), while the second kind of beam has a crescent-shaped intensity distribution. The influence of turbulence on the beam propagation through atmosphere under different turbulence strengths is also numerically studied in this paper. A fractional vortex CAB with an initial radius r0 = 10 mm can retain its shape after propagating 20 m when the atmospheric refractive-index structure constant CN2=0.2×10−12m−2/3. Our results are expected to broaden the application of CABs.

Propagation properties of one-dimensional array vortex beams in a marine atmosphere

Propagation properties of one-dimensional array vortex beams in a marine atmosphere

Propagation of hollow higher-order cosh-Gaussian beam in human upper dermis

Optical detection, measurement, and treatment methods are widely used in the medical industry nowadays. The evolution of radiated beams, received power and beam size play vital roles while developing devices. The propagation properties of hollow higher-order cosh-Gaussian beam (HHOCGB) while propagating in human upper dermis tissue are derived analytically and analyzed numerically. The impact of the hollowness parameter, beam order, operating wavelength, and Gaussian beam waists on the beam’s intensity profile is examined. Received power and beam size variations are analyzed considering operating wavelength and Gaussian waist width. According to the results, as the beam propagates, its profile rapidly evolves into a shape with a circular Gaussian peak in the center and petals at the corner. Dark hollow regions are observed among the petals. Furthermore, the received power by HHOCGBs with a higher Gaussian waist width is more than those received by beams with a lower Gaussian waist width. However, at far field, operating at a lower wavelength prevents the increase of the beam spread. Thus, the obtained results will be significant in the bio-optical disease detection and treatment technology development.

Propagation properties of the Airy vortex beam in the linear potential

In this paper, the propagation properties of the Airy vortex beam (AVB) in the transverse linear potential are investigated analytically and numerically. The analytical expression describing the propagation of the AVB in the linear potential is derived. And it should be noted that the paths of the beam and the optical vortex (OV) are functions of the linear potential. Specifically, by setting a suitable linear potential, it becomes feasible to manipulate the beam and the OV along a predesigned trajectory without altering the peak intensity of the beam or compromising its inherent non-diffracting and self-healing properties. In addition, the off-axis position and the topological charge of the OV are found to have an effect on the position and the magnitude of the beam peak intensity in the linear potential.

Propagation Properties of Vortex Beams in a Helically Twisted Photonic Bandgap Fiber

We propose a helically twisted hollow-core photonic bandgap fiber (PBGF) for orbital angular momentum (OAM) generation. Results demonstrate that this fiber can effectively separate and transmit higher-order OAM modes while reducing crosstalk. The mode effective refractive index curves as a function of wavelength and the transmission characteristics of OAM are investigated in this letter. We show that this fiber has the potential to be used in OAM generators, light-controlling devices, and all-fiber optical communication applications.

Propagation of a radially polarized Hermite-cos-Gaussian correlated Schell-model beam in oceanic turbulence

A new beam called radially polarized Hermite-cos-Gaussian correlated Schell-model (RPHCGSM) beam is proposed. The propagation formulae of an RPHcGSM beam in oceanic turbulence are derived, and the propagation properties of such beam are analyzed. The results show that the spectral density distribution of an RPHcGSM beam in free space can be modulated by γ as distance increases; the beamlets will overlap when an RPHcGSM beam propagating through oceanic turbulence, and the stronger oceanic turbulence can accelerate the speed of beamlets evolving into Gauss beam. Moreover, the degree of polarization can become regular distribution and degree of coherence can become Gaussian distribution due to the influence of oceanic turbulence.

Investigation on propagation properties of a new optical vortex beam: generalized Hermite-cosh-Gaussian beam

Investigation on propagation properties of a new optical vortex beam: generalized Hermite-cosh-Gaussian beam

Propagation properties of hollow rectangular quad-Airy beams

The hollow rectangular quad-Airy beam (HRQAB) is proposed in this paper based on the Fourier transform of the hollow flat-topped Gaussian beam with a cubic phase. The propagation characteristics of HRQAB are investigated in detail. Compared with common quad-Airy beam (QAB), the four focusing property and hollow rectangular profile of this beam are found. In the four-focusing plane, the positions and intensities of the four light spots could be controlled by the initial radius r0, the order of hollow Gaussian beam N, and the coefficient in the cubic phase α. After propagation some distance, a hollow rectangular shape is formed; the area of the hollow region increases significantly with the increase of r0; its intensity of the hollow rectangular light spot would become stronger for a larger α. Finally, the HRQAB is generated in experiment and its special properties are demonstrated.

Propagation properties of cosh-Airy beams in an inhomogeneous medium with Gaussian PT-symmetric potentials

Abstract We numerically investigate and statistically analyze the impact of medium parameters (modulation depth P, modulation factor ω, and gain/loss strength W 0) and beam parameters (truncation coefficient a and distribution factor χ 0) on the propagation characteristics of a cosh-Airy beam in the Gaussian parity-time (PT)-symmetric potential. It is demonstrated that the main lobe of a cosh-Airy beam is captured as a soliton, which varies periodically during propagation. The residual beam self-accelerates along a parabolic trajectory due to the self-healing property. With increment in P, the period of a trapped soliton decreases almost monotonically, while the peak power of a trapped soliton increases monotonically. With the increase in ω or decrease in the absolute value of W 0, the period and peak power of a trapped soliton decrease rapidly and then almost remain unchanged. Moreover, it is indicated that the period of a trapped soliton remains basically unchanged no matter a and χ 0 increase or decrease. The peak power of a trapped soliton increases with increment of a, but the peak power of a trapped soliton stays relatively constant irrespective of variation in χ 0.

Propagation properties of controllable anomalous hollow beams in strongly nonlocal nonlinear media

The evolution properties of controllable anomalous hollow beams (CAHBs) in strongly nonlocal nonlinear medium are studied theoretically and numerically. The CAHB has a circular light intensity distribution, but there is a solid light intensity peak in the center. By changing initial parameters, the central and peripheral light intensities can be adjusted, so the CAHB can represent many different types of beams. The CAHBs in strongly nonlocal media shows a very rich variety of propagation characteristics. The transmission evolution properties of CAHBs, such as the light intensity distribution, the beam width and the on-axis light intensity, are mainly studied. The results show that by choosing appropriate initial parameters, the light intensity pattern of CAHBs can remain unchanged and form solitons, but also change periodically. The beam width of CAHBs can be widened or compressed in two transverse directions at the same time, or widened in one direction and compressed in the other direction. Some typical transmission characteristics are illustrated by numerical simulation, and the role of various parameters in transmission evolution is analyzed.

Paraxial Propagation Properties of Symmetric Dual Pearcey Gaussian Beams in Free Space

AbstractIn this article, a new kind of symmetric dual Pearcey Gaussian beam (SDPGB) is introduced and their properties of auto‐focusing, self‐similarity, inversion, and self‐healing are discussed. The self‐similarity, the auto‐focusing, and the inversion properties of the propagating SDPGBs are turned out by analytical derivation and experimental observation. Additonally, a second‐order chirp factor for SDPGBs is introduced to investigate their secondary auto‐focusing and abrupt auto‐focusing properties in further detail. Finally, the effects of the obstacle diameter and the obstacle placement plane on the self‐healing of the SDPGBs are discussed.

Propagation Characteristics of Circular Airy Vortex Beams in a Uniaxial Crystal along the Optical Axis

Circular airy vortex beams (CAVBs) have attracted much attention due to their “abruptly autofocusing” effect, phase singularity, and their potential applications in optical micromanipulation, communication, etc. In this paper, we numerically investigated the propagation properties of circular airy beams (CABs) imposed with different optical vortices (OVs) along the optical axis of a uniaxial crystal for the first time. Like other common beams, a left-hand circular polarized (LHCP) CAVB, propagating along the optical axis in a uniaxial crystal, can excite a right-hand circular polarized (RHCP) component superimposed with an on-axis vortex of topological charge (TC) number of 2. When the incident beam is an LHCP CAB imposed with an on-axis vortex of TC number of l = 1, both of the two components have an axisymmetric intensity distribution during propagation and form hollow beams near the focal plane because of the phase singularity. The phase pattern shows that the LHCP component carries an on-axis vortex of TC number of l = 1, while the RHCP component carries an on-axis vortex of TC number of l = 3. With a larger TC number (l = 3), the RHCP component has a larger hollow region in the focal plane compared to the LHCP component. We also studied cases of CABs imposed with one and two off-axis OVs. The off-axis OV makes the CAVB’s profile remain asymmetric throughout the propagation. As the propagation distance increases, the off-axis OVs move near the center of the beam and overlap, resulting in a special intensity and phase distribution near the focal plane.

Complex and phase screen methods for studying arbitrary genuine Schell-model partially coherent pulses in nonlinear media.

Partially coherent pulses, especially those with non-Gaussian correlated functions, have rarely been explored in nonlinear media because of the demanding procedure of the widely used coherent-mode representation method. This study develops temporal analogues of the complex screen and phase screen methods, which were recently introduced for the spatial counterpart of a partially coherent beam. These methods were employed to study the beam propagation properties of partially coherent pulses, and the obtained results show that they both are highly precise, convenient, and powerful. We believe that these protocols can effectively provide useful insight into the behavior of many coherence-related phenomena in nonlinear media.

Propagation of sine beam in uniaxial crystal orthogonal to optical axis

AbstractThis study analyzes propagation properties of sine beam in uniaxial crystal orthogonal to optical axis. Huygens‐Fresnel integral is solved to find the received field. Influence of source beam parameters, crystal refractive index settings, and propagation distance is analyzed in detail. Our results yield that intensity concentrates on minimum and maximum of x‐axis at middle and longer propagation distances. Although, sinusoidal waveform is conserved at close distance. We hope that these results will be used in optical tracking applications.

A quantitative method for in situ pump-beam metrology in 4D ultrafast electron microscopy

We report a method for measuring spot size and focusing conditions of the femtosecond (fs) excitation laser in situ at the specimen location in 4D ultrafast electron microscopy (UEM). The method makes use of threshold laser ablation behaviors of thin amorphous carbon membranes. For Gaussian beam profiles and for ablation threshold fluence values, we analytically derive expressions describing the relationship between ablated hole size and the actual laser spot size. Using these expressions, we developed experimental procedures for characterizing the shape and spot size of the pump beam at the specimen. We demonstrate the viability of the approach for incident excitation wavelengths of 343 nm and 515 nm, thus illustrating the applicability of the method to a range of optical wavelengths without modification. Further, we show that by measuring ablated hole size as a function of focusing condition, a full metrological characterization of the Gaussian beam propagation properties can be performed. Finally, we find good agreement for spot sizes determined with this method and with those determined by extrapolation from measurements taken outside the microscope column. Overall, this method is a simple, cost-effective means for accurate and precise determination of key pump-beam parameters in situ at the specimen location in UEM experiments.

Propagation properties of finite Airy beams on curved surfaces.

Airy beams have provided exciting inspiration in the field of optical communication, particle manipulation, and imaging. We investigate the propagation properties of the exponential truncation Airy beams (ETABs) on constant Gaussian curvature surfaces (CGCSs) in this paper. The analytical expression of the electric field of ETABs propagating on the CGCSs is derived. It shows that the equivalent periodical accelerations of the trajectories of ETABs on the curved surface are always larger than the constant one on the flat surface because the CGCSs have a strong focusing ability. For the same reason, the non-diffraction propagation of ETABs is found when the focusing ability of the CGCSs is strong enough. Moreover, we investigate the self-healing length of ETABs on CGCSs and explore that the ability of self-healing is related to the geometry of CGCSs besides the width of the block and the size of the beam. The self-healing length gets larger with the increase of radius of CGCSs and finally consists with that on the flat surface. These propagation characteristics are different from those in the flat space and are useful for the future applications of ETABs in particle manipulation on waveguides, light-sheet fluorescence microscopy, curved nanophotonics, and so on.

Propagation Properties of Multi-Hyperbolic Sine-Correlated Beams in Oceanic Turbulence

As a new partially coherent beam, the propagation properties of the multi-hyperbolic sine-correlated (MHSC) beams in turbulent atmospheres have been studied. But as another important medium, the propagation properties of MHSC beams in oceanic turbulence. This paper has studied these questions in detail. The analytical formulas of spectral density and degree of coherence for the propagation are derived and the numerical simulations are represented. It is found that the intensity patterns of MHSC beams will evolve from dark-hollow profiles into Gaussian profiles caused by oceanic turbulence and will degenerate more rapidly with stronger oceanic turbulence. In addition, the coherence region becomes larger with decreasing in the dissipation rate of turbulence kinetic energy in unit mass liquid or increasing in the relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. We also find that the degree of coherence of MHSC beams with a higher-order N will decrease more slowly than those of hyperbolic sine-correlated (HSC) beams.