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Diffractive Elements
Published in Daniel Malacara-Hernández, Brian J. Thompson, Fundamentals and Basic Optical Instruments, 2017
Other beam shapers include the Laguerre–Gaussian beam, which has a phase singularity that propagates along its axis [86]. Work has also been done to convert a Gaussian-profile beam into a uniform-profile beam in a one-dimensional optical system as well as rotationally symmetric optical systems both for different fractional orders and different parameters of the beam [87]. Another important application is the pseudo-nondiffracting beam DE, characterized by an intensity distribution that is almost constant axially over a finite axial region and a long propagation distance along the optical axis [88] and the axicons. An axicon is an optical element that produces a constant light distribution over a long distance along the optical axis. A diffractive axicon with a discrete phase profile can be fabricated using lithographic fabrication techniques. Other elements can be fabricated with linear phase profiles [89].
Focusing Laser Light by Axicon and Zone Plate
Published in Victor V. Kotlyar, Sergey S. Stafeev, Anton G. Nalimov, Sharp Focusing of Laser Light, 2019
Victor V. Kotlyar, Sergey S. Stafeev, Anton G. Nalimov
A binary axicon is easier to manufacture compared to the conical axicon discussed in the previous section. The binary axicon can be manufactured by photolithography using a single binary amplitude mask composed of concentric bright and dark rings of equal width. Shown in Figure 1.6 is the radial profile of a binary microaxicon corresponding to the conical axicon in Figure 1.2.
Freeform axicon with azimuthal variation
Published in Journal of Modern Optics, 2020
Rafael G. González-Acuña, Julio C. Gutiérrez-Vega, Michelle C. Rocha
An axicon is an optical element that images an axial point into a line along the optical axis. The typical shape of an axicon is a cone with a flat input surface made of translucent material with a constant refraction index. J. H. McLeod was the first researcher to report the properties of glass cones in 1954 [1]. Beyond to the axial line, the axicon projects a divergent circular ring in the far-field that has been applied in a variety of situations [2,3]. From the wave optics point of view, an axicon is a device that transforms an incident collimated wave into a converging conical wave. This property has proved to be very useful in generating non-diffracting like Bessel beams, X-waves, and conical waves both in passive optical systems and active cavity resonators [4–6]. The axicon has useful applications for modern optical systems, for example, in high-resolution imaging, for increasing the depth of field, and for iris image acquisition systems [7–9].
The existence and evolution of fast-decaying Bessel modes in cylindrical hollow waveguides and in free space
Published in Journal of Modern Optics, 2019
G. Nyitray, A. Nagyváradi, M. Koniorczyk
Since the Hankel transform of an ideal Bessel beam yields which implies , hence the plane waves (k-vectors of the Bessel mode) propagating on a cone. The opening angle of the cone is often referred as an axicon angle.