Generation of Bessel beam arrays through Dammann gratings (original) (raw)
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Generation of nondiffracting Bessel beams by use of a spatial light modulator
Optics Letters, 2003
A laser beam with phase singularities is an interesting object to study in optics and may have important applications in guiding atoms and molecules. We explore the characteristics of a singularity in a nondiffracting Bessel beam experimentally by use of a programmable spatial light modulator with 64-level phase holograms. The diffraction efficiency with 64-level phase holograms is greatly improved in comparison with that obtained with a binary grating. The experiments show that the size and def lection angle of the beam can be controlled in real time. The observations are in agreement with scalar diffraction theory.
Digital generation of shape-invariant Bessel-like beams
Optics Express, 2015
Bessel beams have been extensive studied to date but are always created over a finite region inside the laboratory. Means to overcome this consider multi-element refractive designs to create beams that have a longitudinal dependent cone angle, thereby allowing for a far greater quasi non-diffracting propagation region. Here we outline a generalized approach for the creation of shape-invariant Bessel-like beams with a single phaseonly element, and demonstrate it experimentally with a phase-only spatial light modulator. Our experimental results are in excellent agreement with theory, suggesting an easy-to-implement approach for long range, shapeinvariant Bessel-like beams.
Generation of generalized spiraling Bessel beams of arbitrary order by curved fork-shaped holograms
Optical and Quantum Electronics, 2016
Generalized spiraling Bessel beams (GSBB) of arbitrary order are created by illuminating a curved fork-shaped hologram (CFH) by Laguerre-Gaussian beam (LGB). The analytical expressions of the diffracted wave field amplitudes and intensities are calculated and analyzed using the stationary phase method. The numerical results are given to understand the features of the GSBB by using CFH. Our finding provides the study of the LGB with null mode number n and azimuthal mode index l and the fundamental Gaussian beam through the considered optical system, which are as particular cases of the present investigation.
Efficient generation of Bessel beam arrays by means of an SLM
The European Physical Journal Special Topics, 2011
We use a Spatial Light Modulator (SLM) to produce arrays of Bessel beams by using multiple axicon phase-masks on the SLM. This approach utilises the whole of the SLM, rather than just a thin annular region (which is the case if the SLM is in the far-field of the generated Bessel beams). Using the whole SLM rather than just an annular region means that the required intensity on the SLM is an order of magnitude lower for a given power in the Bessel beams. Spreading the power over the whole SLM is important for high-power applications such as laser micromachining. We allow the axicons to overlap and interfere in the hologram, so the axial length of the Bessel beam core is maintained as we add more beams to the array. a
Diffractive optics for axial intensity shaping of Bessel beams
Journal of Optics
Bessel beams (BBs) appear to be immune to diffraction over finite propagation distances due to the conical nature of light propagation along the optical axis. This offers promising advantages in laser fabrication. However, BBs exhibit a significant intensity variation along the direction of propagation. We present a simple technique to engineer the axial intensity of the BBs over centimeter-long propagation distances without expansion of the incoming laser beam. This method uses two diffractive optical elements (DOEs), one converts the input Gaussian intensity profile to an intermediate intensity distribution, which illuminates the second DOE, a binary axicon. BBs of a desired axial intensity distribution over a few centimeters length can be generated.
Multilevel Spiral Axicon for High-Order Bessel–Gauss Beams Generation
Nanomaterials
This paper presents an efficient method to generate high-order Bessel–Gauss beams carrying orbital angular momentum (OAM) by using a thin and compact optical element such as a multilevel spiral axicon. This approach represents an excellent alternative for diffraction-free OAM beam generation instead of complex methods based on a doublet formed by a physical spiral phase plate and zero-order axicon, phase holograms loaded on spatial light modulators (SLMs), or the interferometric method. Here, we present the fabrication process for axicons with 16 and 32 levels, characterized by high mode conversion efficiency and good transmission for visible light (λ = 633 nm wavelength). The Bessel vortex states generated with the proposed diffractive optical elements (DOEs) can be exploited as a very useful resource for optical and quantum communication in free-space channels or in optical fibers.
Generation of V-point polarization singularity array by Dammann gratings
Applied Physics B, 2022
A liquid crystal Spatial Light Modulator (SLM) can be used in various ways to produce vector-vortices. Superposition of scalar vortices with orthogonal polarization is a common approach, while a more recent technique is to use dual-phase modulation. These approaches require modulation of at least two phase patterns with a SLM or multiple SLMs. In this paper, we propose a novel technique to produce vector-vortices by modulating orthogonal light components through a single phase pattern with a SLM. It does not require interferometric setups, and simplifies the generation of light beams with V-point polarization singularities. Because of compact and robustness of our experimental setup, it can be easily integrated to any device for applications of vector-vortices. The importance of optical vortices has grown significantly in recent years due to their unique properties, which have enabled a plethora of applications 1,2. Vortex beams are characterized by a helical-shaped wavefront which creates a phase singularity along their beam axis, resulting in a doughnut-shaped intensity profile. As-such, they are often referred to as doughnut beams. The optical field of a vortex beam can be expressed as,
High-quality vector vortex arrays by holographic and geometric phase control
Journal of Physics D: Applied Physics, 2020
Cylindrical vector vortex (CVV) beams are topical forms of structured light, and have been studied extensively as single beams, non-separable in two degrees of freedom: spatial mode and polarisation. Here we create arrays of CVV beams using a combination of dynamic phase controlled Dammann gratings and spin–orbit coupling through azimuthally varying geometric phase. We demonstrate control over the number, geometry and vectorness of the CVV arrays by simple adjustment of waveplates and computer generated holograms. To quantify the efficacy of our approach, we employ a recently proposed vector quality factor analysis, realising high quality vector beam arrays with purities in excess of 95%. Our approach is scalable in array size, robust (no interferometric beam combination) and allows for the on-demand creation of arbitrary vector beam arrays, crucial for applications that require multi-spot arrays, for example, in fast laser materials processing, multi-channel communication with spat...
Optics letters, 2004
Propagation-invariant vectorial Bessel beams with linearly polarized axial symmetry based on quantized Pancharatnam -Berry phase optical elements are described. The geometric phase is formed through the use of discrete computer-generated space-variant subwavelength dielectric gratings. We have verified the polarization properties of our elements for laser radiation at 10.6-mm wavelength and also demonstrated propagation-invariant, controlled rotation of a propeller-shaped intensity pattern through the simple rotation of a polarizer.