We theoretically and experimentally studied a novel class of vortex beams named open vortex beams (OVBs). Such beams are generated using Gaussian beams diffracted by partially blocked fork-shaped gratings (PB-FSGs).The analytical model of OVBs in the near field and far field is given by superpositions of Hypergeometric (HyG) modes. Unlike conventional integer and fractional vortex beams, the OVBs can have both an open ring structure and an integer topological charge (TC). The TC is decided by the circumference covered by the open ring. It is also quantitatively shown that a $π/2$ rotation of the open ring occurs in the propagation of an OVB due to the Gouy phase shift. Futhermore, we demonstrate experimental generation and detection of OVBs. Our experimental results are in very good agreement with the theory. We believe that the OVB can be the potential candidate for numerous applications, such as particle manipulation, quantum information and optical metrology.
Propagation of optical vortex beamlet (OVB) in turbulent atmospheric environment is studied theoretically by normalized models. Our simulation shows that optical vortex beamlet is superior to traditional Gaussian beam in terms of diffraction behavior of long haul propagation. Formation of vortex beam let is experimentally demonstrated by using a spatial light modulator (SLM), which achieve a power efficiency of more than 90% when the intrinsic loss in SLM is excluded.
We demonstrate theoretically that few-cycle vortex beam with subterawatt peak power can be generated by self-compression of mid-infrared femtosecond vortex beam using the thin-plate scheme. The 3 μm femtosecond vortex beam with input duration of 90 fs is compressed to 15.1 fs with the vortex characteristics preserved. The conversion efficiency is as high as 91.5% and the peak power reaches 0.18 TW. The generation of the high-peak-power few-cycle vortex beam is owing to the proper spatiotemporal match by this novel scheme, where the spectrum is broadened enough, the negative group velocity disp…
Reformulation of conventional beam definitions into their bidirectional versions and use of Hertz potentials make beam fields exact vector solutions to Maxwell's equations. This procedure is applied to higher-order elegant Laguerre-Gaussian beams of TM and TE polarization. Their vortex and anti-vortex co-axial compositions of equal and opposite topological charges are given in a closed analytic form. Polarization components of the composed beams are specified by their radial and azimuthal indices. The longitudinal components are common for beam compositions of both types, meanwhile their trans…
We study propagation of a pair of oppositely charged and mutually incoherent vortices in anisotropic nonlinear optical media. Mutual interactions retard the delocalization of the vortex core observed for isolated vortices.
Vortex beams are stable solutions of Maxwell's equations that carry phase singularities and orbital angular momentum, unique properties that give rise to many applications in the basic sciences, optical communications, and quantum technologies. Scalable integration and fabrication of vortex beam emitters will allow these applications to flourish and enable new applications not possible with traditional optics. Here we present a general framework to generate integrated vortex beam emitters using photonic inverse design. We experimentally demonstrate generation of vortex beams with angular momen…
Fractional vortex beams (FVBs) with non-integer topological charges attract much attention due to unique features of propagations, but there still exist different viewpoints on the change of their total vortex strength. Here we have experimentally demonstrated the distribution and number of vortices contained in FVBs at Fraunhofer diffraction region. We have verified that the jumps of total vortex strength for FVBs happens only when non-integer topological charge is before and after (but very close to) any even integer number, which originates from two different mechanisms for generation and m…
We consider the propagation of a tilted high order paraxial vortex-beam through a homogeneous anisotropic medium of a uniaxial crystal. We found that the initially circularly polarized beam bearing the l-order optical vortex splits into ordinary and extraordinary beams with a complex vortex structure. After a series of dislocation reactions the vortices gather together at the axis of the partial beam with the initial circular polarization shaping the l-order optical vortex. However, only l-1 vortices gather together on the axis of the partial beam with the orthogonal circular polarization. One…
Wavefront engineering is an important quantum technology. Here, we demonstrate the design and production of a robust C-shaped and orbital angular momentum (OAM) carrying beam in which the doughnut shaped structure contains an adjustable gap. We find that the presence of the vortex line in the core of the beam is crucial for the robustness of the C-shape against beam propagation. The topological charge of the vortex core controls mainly the size of the C, while its opening angle is controlled by the presence of vortex-anti-vortex loops. We demonstrate the generation and characterisation of C-sh…
We report a novel experimental scheme for single-pass second harmonic generation (SHG) of vector vortex beam in the blue. Using an ultrafast Ti:Sapphire laser of pulse width ~17 fs and a set of spiral phase plates in polarization based Mach-Zehnder interferometer (MZI) we have generated vector vortex beams of order as high as lp = 12 at an average power of 860 mW. Given the space-variant polarization of the vector vortex beam, and the dependence of nonlinear frequency conversion processes on the polarization of the interacting beams, using two contiguous bismuth borate crystals with optic axis…
Traditional fractional vortex beams are well-known "jump" beams: that is, their net topological charge jumps by unity as the effective topological charge of the source passes a half-integer value. Here, we propose an anomalous multi-ramp fractional vortex (AMRFV) beam. Unlike the traditional fractional vortex beams, an AMRFV beam can be designed to have arbitrary jumps in topological charge at any critical threshold of the source charge. We walk through some examples of AMRFV beams using simulations and present a clear interpretation of the multi-jump characteristic based on the evolution of p…
Using acoustooptic (AO) cells based on TeO2 crystal and silica glass, we have experimentally shown for the first time that the intensity profile and the phase structure of the vortex beam are preserved under AO Bragg diffraction. As a result, the vortex beam can be deflected due to AO diffraction, whereas the acoustooptically operated vortex beams can be efficiently used in such novel branches of optical technology as optical trapping and controlled addressing of the beams with different orbital angular momentums.
We describe nonlinear Bessel vortex beams as localized and stationary solutions with embedded vorticity to the nonlinear Schrödinger equation with a dissipative term that accounts for the multi-photon absorption processes taking place at high enough powers in common optical media. In these beams, power and orbital angular momentum are permanently transferred to matter in the inner, nonlinear rings, at the same time that they are refueled by spiral inward currents of energy and angular momentum coming from the outer linear rings, acting as an intrinsic reservoir. Unlike vortex solitons and diss…
An optical vortex, produced at one point in an optical beam, would propagate through an optical system to another point where the vortex can be used for some purpose. However, asymmetrical optical elements in such a system can cause astigmatism or at least distroy the rotational symmetry of the beam, which may affect the propagation of the vortex in an undesirable way. While an optical vortex in a rotationally symmetric, stigmatic Gaussian beam retains its initial morphology for as far as it propagates, the morphology of an optical vortex in an asymmetric or astigmatic Gaussian beam changes. T…
Nonlinear Bessel beams in self-defocusing media are found to be the natural, non-diffracting background where vortex solitons can be nested, interact and survive for propagation distances that are one order of magnitude larger than in the usual Gaussian or super-Gaussian backgrounds. The dynamics of the vortex solitons approaches that in the ideal, uniform background, preventing vortex spiraling and decay, which eases vortex steering for applications.
We study the self-focusing dynamics and collapse of vortex Airy optical beams in a Kerr medium. The collapse is suppressed compared to a non- vortex Airy beam in a Kerr medium as a result of the existence of vortex fields. The locations of collapse depend sensitively on the initial power, vortex order, and modulation parameters. Unlike the collapses reported before for any beam, the collapse may occur in a position where the initial field is nearly zero while no collapse appears in the region where the initial field is mainly distributed. This study sheds light on how to control and manipulate…
Optical vortex beams have been under considerable attention recently due to their demonstrated potential for applications ranging from optical communication to particle trapping. Practical problems related to the dependence between their phase structure and the physical size have been addressed by introducing the concept of perfect optical vortex beams. Propagation of these structured beams through different levels of disturbances is critical for their uses. For the first time, we examine quantitatively the degradation of perfect optical vortex beams after their interaction with localized rand…
We demonstrate theoretically and experimentally coherence-induced polarization changes in generic and higher-order vector vortex beams with polarization singularity. The prominent depolarization on decreasing transverse correlation-width in focused partially coherent vector vortex beam provides a means to shape the intensity profile and the degree of polarization (DOP) while preserving the polarization distribution. The intensity variation and DOP-dip are found to be dependent on the polarization singularity index of the beam. Our results may provide an additional degree of freedom in the myri…
Numerical simulation is used to analyze statistical characteristics of vortex beams propagating in the atmosphere. The cumulative distribution function and the probability density function of intensity fluctuations are compared for Gaussian beams and vortex beams. It is shown that for propagation conditions in the turbulent atmosphere corresponding to weak fluctuations (Rytov parameter much smaller than unity), intensity fluctuations at the axis of the Gaussian beam have the lognormal distribution, whereas the probability density distribution of the radiation intensity fluctuations at the axis…
We show that a high-order Bessel beam propagating in a medium with nonlinear absorption is not completely absorbed, but survives in the form of a new propagation invariant vortex beam in which the beam energy and orbital angular momentum are permanently transferred to matter and at the same time refueled by spiral inward currents of energy and angular momentum. Unlike vortex solitons and dissipative vortex solitons, these vortex beams are not supported by specific dispersive nonlinearities (self-focusing or self-defocusing) and do not require gain. Propagation invariance in presence of multipl…
With the increasing demand for potential applications in almost all fields in modern optics, the generation of vortex beams has attracted significant interest. Based on a flat plate made of electro-optical crystals, we propose an electrically controlling method to generate vortex beams assisted by the Pockels effect. Compared with traditional methods, our method allows flexibly tuning the wavelength and topological charge of the generated optical vortex beams. We simulate the propagation of optical beams transmitted from the flat plate and investigate the orbital-angular-momentum(OAM)-mode spe…
Friedel's law states that the modulus of the Fourier transform of real functions is centrosymmetric, while the phase is antisymmetric. As a consequence of this, elastic scattering of plane wave photons or electrons within the first-order Born-approximation as well as Fraunhofer diffraction on any aperture, is bound to result in centrosymmetric diffraction patterns. Friedel's law, however, does not apply for vortex beams, and centrosymmetry in general is not present in their diffraction patterns. In this work we extend Friedel's law for vortex beams by showing that the diffraction patterns of v…
The work defines the general form of the Jones vector and establishes the Jones matrix for polarizers, wave plates, Faraday rotators, Q-plates, and spiral phase plates. We establish the generalized Jones calculus for vortex, vector, and vortex-vector beam transformations. Systematic formalism presents the theoretical arrangements in the manipulation of the phase and polarization of the structured lights. The eigenstates and the time-reversal behaviors of optical components and systems are discussed through matrix algebra. The generalized Jones calculus is then used in the characterization of S…
We demonstrate numerically and experimentally the generation of powerful supercontinuum vortices from femtosecond vortex beams by using multiple thin fused silica plates. The supercontinuum vortices are shown to preserve the vortex phase profile of the initial beam for spectral components ranging from 500 nm to 1200 nm. The transfer of the vortex phase profile results from the inhibition of multiple filamentation and the preservation of vortex ring with relatively uniform intensity distribution by means of the thin-plate scheme, where the supercontinuum is mainly generated from the self-phase …
A novel approach based on the two-channel moiré deflectometry has been used to measure both wave-front and transverse component of the Poynting vector of an optical vortex beam. Generated vortex beam by the q-plate, an inhomogeneous liquid crystal cell, has been analyzed with such technique. The measured topological charge of generated beams are in an excellent agreement with theoretical prediction.
We measure the far-field intensity of vortex beams going through nanoholes. The process is analyzed in terms of helicity and total angular momentum. It is seen that the total angular momentum is preserved in the process, and helicity is not. We compute the ratio between the two transmitted helicity components, $γ_{m,p}$. We observe that this ratio is highly dependent on the helicity ($p$) and the angular momentum ($m$) of the incident vortex beam in consideration. Due to the mirror symmetry of the nanoholes, we are able to relate the transmission properties of vortex beams with a certain helic…
A Highly flexible and efficient method of generating stable radially and Azimuthally polarized perfect optical vortex beams and all higher-order cylindrical vector vortex beams are proposed and demonstrated. The method is the most convenient implementation of the superposition of two orthogonally circularly polarized optical vortex beams of arbitrary integer topological charges. By simply controlling the relative amplitude and phase between vertical and horizontal polarization component of an input perfect vortex beam on a phase-sensitive Spatial Light Modulator (SLM) and using a common-path i…
We study, analytically and numerically, reflection and transmission of an arbitrarily polarized vortex beam on an interface separating two dielectric media and derive general expressions for linear and angular Goos-Hanchen and Imbert-Fedorov shifts. We predict a novel vortex-induced Goos-Hanchen shift, and also reveal direct connection between the spin-induced angular shifts and the vortex-induced linear shifts.
We report the fabrication of large-area phase masks on thin fused-silica substrates that are suitable for shaping multi-terawatt femtosecond laser beams. We apply these phase masks for the generation of intense femtosecond optical vortices. We further quantify distortions of the vortex beam patterns that result from several common types of mask defects.
We originally demonstrate the vortex beams with patterns of closed polygons [namely polygonal vortex beams (PVBs)] generated by a quasi-frequency-degenerate (QFD) Yb:CALGO laser resonator with astigmatic transformation. The PVBs with peculiar patterns of triangular, square, and parallelogram shapes carrying large orbital angular momentums (OAMs) are theoretically investigated and experimentally obtained in the vicinity of the SU(2) degenerate states of laser resonator. The PVBs in QFD states are compared with the vortex beams with patterns of isolated spots arrays located on the triangle-, squ…
We present the experimental generation and analysis of both the intensity and phase of an optical vortex beam originating from a superposition of Airy-vortex beams. A new theoretical proposal is accessible to generate an array of Airy-vortex beams (AiVBs) from a superposition of N identical AiBs symmetrically located with respect to the propagation axis, where each beam is superimposed with OV and are characterized by the same topological charge l. Additionally, a single experimental apparatus enables both the optical generation and reconstruction of computer-generated holograms implemented on…
Electron vortex beams hold great promise for development in transmission electron microscopy, but have yet to be widely adopted. This is partly due to the complex set of interactions that occur between a beam carrying orbital angular momentum (OAM) and a sample. Herein, the system is simplified to focus on the interaction between geometrical symmetries, OAM and topology. We present multiple simulations, alongside experimental data to study the behaviour of a variety of electron vortex beams after interacting with apertures of different symmetries, and investigate the effect on their OAM and vo…
Vortex beams with orbital angular momentum has been attracting tremendous attention due to their considerable applications ranging from optical tweezers to quantum information processing. Metalens, an ultra-compact and multifunctional device, provide a desired platform for designing vortex beams. A spin-dependent metalens can boost the freedom to further satisfy practical applications. By combining geometric phase and propagation phase, we propose and demonstrate an approach to design a spin-dependent metalens generating dual-focused vortex beams along longitudinal or transverse direction, i.e…
We presented a new method for measuring the squares of the amplitudes and phases of partial vortex-beams in a complex beam array in real time. The method is based on measuring the high-order intensity moments and analyzing the solutions of a system of linear equations. Calibration measurements have shown that the measurement error at least for an array of 10-15 beams does not exceed 4%. When measuring beams with different fractional topological charge of optical vortices, we revealed a sharp decrease in the OAM for small deviations of the topological charge from the integer order which is asso…
We consider theoretically and experimentally the precession of the optical vortex in a singular beam propagating nearly perpendicular to the crystal optical axis, the beam and the crystal axis rotating with different angular velocities. The precession is a result of different scales along the major axes in a uniaxial crystal. Also we analyze the properties of the optical reducer consisting of two rotating crystals and a wave retarder between them permitting us to control the form of the vortex trajectory.
We present a simple and efficient method to generate any cylindrical vector vortex (CVV) beams based on two cascaded metasurfaces. The metasurface works as a space-variant Panchratnam-Berry phase element and can produce any desirable vortex phase and vector polarization. The first metasurface is used to switch the sign of topological charges associated with vortex, and the second metasurface is applied to manipulate the local polarization. This method allows us to simultaneously manipulate polarization and phase of the CVV beams.
We report on experimental demonstration of high power, ultrafast, high repetition rate vortex beam source tunable in the near-IR wavelength range. Based on single-pass optical parametric generation of Yb-fiber laser of vortex order lp=1 in a 50 mm long MgO doped periodically poled LiNbO3 crystal, the source produces signal beam in vortex profile of order ls=1 across 1433-1553 nm. Additionally, the source produces broadband idler radiation tunable across 3379-4132 nm in the Gaussian beam profile. We observed that the vortex profile of the pump beam is always transferred to the signal beam due t…
Discretized vortex-producing lenses programmed on low performance spatial light modulators have been used for the generation of optical vortices. However, the description of these vortices has been supported only by numerical simulations. In this work, a general analytical treatment (any topological charge - any discretization levels) for the propagation of a Gaussian beam through a discretized vortex-producing lens is presented. The resulting field could be expressed as a sum of Kummer beams with different amplitudes and topological charges focalized at different planes, whose characteristics…
Model equations for describing and efficiently computing the radiation profiles of tightly spherically-focused higher-order electromagnetic beams of vortex nature are derived stemming from a vectorial analysis with the complex-source-point method. This solution, termed as a high-order quasi-Gaussian (qG) vortex beam, exactly satisfies the vector Helmholtz and Maxwell's equations. It is characterized by a nonzero integer degree and order (n,m), respectively, an arbitrary waist w0, a diffraction convergence length known as the Rayleigh range zR, and an azimuthal phase dependency in the form of a…
Perfect vortex beams are the orbital angular momentum (OAM)-carrying beams with fixed annular intensities, which provide a better source of OAM than traditional Laguerre- Gaussian beams. However, ordinary schemes to obtain the perfect vortex beams are usually bulky and unstable. We demonstrate here a novel generation scheme by designing planar Pancharatnam-Berry (PB) phase elements to replace all the elements required. Different from the conventional approaches based on reflective or refractive elements, PB phase elements can dramatically reduce the occupying volume of system. Moreover, the PB…
We have derived the corresponding equations and found their solutions both for nonparaxial and paraxial beams. The paraxial solutions we have presented in the form of the generalized Hermite-Gaussian beams propagating perpendicular to the optical axis of a uniaxial crystal. We have also constructed the generalized Laguerre-Gaussian beams at the z=0 plane and analyzed their evolution in a homogeneous isotropic medium. Comparing it with the evolution of the standard Laguerre-Gaussian beams with and in the crystal we have revealed that the additional elliptic deformation of the extraordinary beam…
In this work a method for generating a long-range optical pulling force is presented which is realized by utilizing a vortex beam and a device designed based on transformation optics through conformal mapping. The device works by transforming an input perfect vortex beam into an almost non-paraxial plane wave, and generates a pulling force by maximizing the forward momentum of the beam. A three-dimensional full-wave analysis of the device is performed and the optical force is computed by the Maxwell stress tensor method. The simulation results show a very good agreement with the theoretical ca…
We detect the vortex evolution from the increase of the fractional phase step by interfering two beams of opposite but equal fractional step increment.The interference pattern generated shows evidence of the birth of an additional single extra charge as the fractional phase step increase extends above a half-integer value
We have theoretically predicted the gigantic spikes of the orbital angular momentum caused by the conversion processes of the centered optical vortex in the circularly polarized components of the elliptic vortex beam propagating perpendicular to the crystal optical axis. We have experimentally observed the conversion process inside the subwave deviations of the crystal length. We have found that the total orbital angular momentum of the wave beam is conserved.
To exploit the full potential of the transverse spatial structure of light using the Laguerre-Gaussian basis, it is necessary to control the azimuthal and radial components of the photons. Vortex phase elements are commonly used to generate these modes of light, offering precise control over the azimuthal index but neglect the radially dependent amplitude term which defines their associated corresponding transverse profile. Here we experimentally demonstrate the generation of high purity Laguerre-Gaussian beams with a single step on-axis transformation implemented with a dielectric phase-ampli…
The analytical solution for the propagation of the laser beam with optical vortex through the system of lenses is presented. The optical vortex is introduced into the laser beam (described as Gaussian beam) by spiral phase plate. The solution is general as it holds for the optical vortex of any integer topological charge, the off-axis position of the spiral phase plate and any number of lenses. Some intriguing conclusions are discussed. The higher order vortices are unstable and split under small phase or amplitude disturbance. Nevertheless, we have shown that off-axis higher order vortices ar…
One of the challenges for every optical system is preserving the quality of the used beam, which may be significantly reduced, due to the low condition of used optical elements or their misalignment. There are plenty of methods focused on the correction of the final beam, depending on the used entire optical system. The problem of efficient beam evaluation is just as important. So far, most of the measurements, are based on visual inspection, which is not always enough, especially when the high quality of the beam is required. Novel approaches use structured light to increase beam sensitivity …
A method to generate the optical vortex beam with arbitrary superposition of different orders of orbital angular momentum (OAM) on a photonic chip is proposed. The distributed Fourier holographic gratings are proposed to convert the propagating wave in waveguides to a vortex beam in the free space, and the components of different OAMs can be controlled by the amplitude and phases of on-chip incident light based on the principle of Fourier transformation. As an example, we studied a typical device composed of nine Fourier holographic gratings on fan-shaped waveguides. By scalar diffraction calc…
An absorptive Rayleigh dielectric sphere in a non-diffracting non-paraxial fractional Bessel vortex beam experiences a spin torque. The axial and transverse radiation spin torque components are evaluated in the dipole approximation using the radiative correction of the electric field. Particular emphasis is given on the polarization as well as changing the topological charge and the beam's half-cone angle. When the beam order is zero, the axial spin torque component vanishes. However, when the beam order becomes a real positive number, the vortex beam induces left-handed (negative) axial spin …
A new method to generate and control the amplitude and phase distributions of a optical vortex beam is proposed. By introducing a holographic grating on top of the dielectric waveguide, the free space vortex beam and the in-plane guiding wave can be converted to each other. This microscale holographic grating is very robust against the variation of geometry parameters. The designed vortex beam generator can produce the target beam with a fidelity up to 0.93, and the working bandwidth is about 175 nm with the fidelity larger than 0.80. In addition, a multiple generator composed of two holograph…
In recent years, optical vortex beams possessing orbital angular momentum have caught much attention due to their potential for high capacity optical communications. This capability arises from the unbounded topological charges of orbital angular momentum (OAM) that provides infinite freedoms for encoding information. The two most common approaches for generating vortex beams are through fork diffraction gratings and spiral phase plates. While realization of conventional spiral phase plate requires complicated 3D fabrication, the emerging field of metasurfaces has provided a planar and facile …
Spatial characteristics of diffracted beams produced by the "fork" holograms from incident circular Lauerre-Gaussian modes are studied theoretically. The complex amplitude distribution of a diffracted beam is described by models of the Kummer beam or of the hypergeometric-Gaussian beam. Physically, in most cases its structure is formed under the influence of the divergent spherical wave originating from the discontinuity in the beam spatial profile or its derivatives caused by the hologram's groove bifurcation. Presence of this wave is manifested by the ripple structure in the near-field diffr…
It was recently realized that the polarization bases of the plane-wave modes in the integral representation of a light beam need to be determined by a degree of freedom arising from the divergence-free Maxwell's equation. This is a frequently introduced real unit vector in the literature, called Stratton vector. The polarization bases so determined are singular at the momentum that is parallel to the Stratton vector. Here we show that the polarization singularity of vector vortex beams given by the integral representation comes from the singularity of the polarization bases in association with…
In this paper we show a method for creating multiple independent quasi-perfect vector vortex beams with real-time programmable radii, topological charges, polarization orders and position in 3 dimensions, using a device based on a phase-only liquid crystal on silicon display. We achieved the simultaneous generation of up to 7 independent beams, with topological charges from -3 to 3, and found great agreement between the simulated and the measured phases and polarization structures. Additionally, we used the same scheme for enhancing the depth of focus of a single beam, resulting in a "tube" be…
We have experimentally investigated the evolution properties of multiramp fractional vortex beams (MFVBs) in free space, by using a fundamental Gaussian beam reflecting from a phase-modulated spatial light modulator. The issue about the total vortex strength of such MFVBs is systematically addressed, and our result reveals the dependence of the total vortex strength depends on both the non-integer topological charge $α$ and the multiramp number $m$ contained in initial multiramp phase structures. In the near-field region, vortices contained in MFVBs are unstable and it is hard to effectively c…
We experimentally demonstrated a high-order optical vortex pulsed laser based on a mode selective all-fiber fused coupler composed of a single-mode fiber (SMF) and a few-mode fiber (FMF). The fused SMF-FMF coupler inserted in the cavity not only acts as mode converter from LP01 mode to LP11 or LP21 modes with a broadband width over 100 nm, but also directly delivers femtosecond vortex pulses out of the mode locked cavity. To the best of our knowledge, this is the first report on the generation of high-order pulse vortex beams in mode-locked fiber laser. The generated 140 femtosecond vortex bea…
A vector wave analysis of nondiffracting beams propagating along a birefringent chiral crystal for the case of tensor character both of the optical activity and linear birefringence is presented, fields of eigen modes satisfying vector wave equation. We have written characteristic equations and found propagation constants and amplitude parameters of eigen modes. We have shown that the field of eigen modes is non-uniformly polarized in the beam cross-section. We have revealed that even a purely chiral crystal without a linear birefringent can generate optical vortices in an initially vortex-fre…
We use phase-shifting digital holography to measure the amplitude and phase of twisted light. In our experiment, a spatial light modulator generates the studied vortex beams in addition to a co-propagating reference beam with a controllable relative phase. We show complex field measurements for single and superposition Laguerre Gaussian (LG) modes, demonstrate full modal decompositions into LG and orbital angular momentum (OAM) power spectral bases, provide error analysis and demonstrate high insensitivity to detector misalignment to show the robustness of the technique. This enables rapid det…
