Design, fabrication, and evaluation of diffractive optical elements for generation of focused ring patterns
19 Feb 2015-Vol. 9449, pp 944902
TL;DR: In this paper, a toric Fresnel zone lens and composite elements were fabricated using electron beam direct writing for the generation of focused ring patterns, with the toric lens out-performing the other elements in several areas such as efficiency, focal depth, and ring thickness.
Abstract: Focused ring patterns are used for many applications like corneal surgery, micro drilling, optical trapping, etc. The generation of focused ring patterns in the earlier reported cases employed many refractive optical components with different functions. As a result the optics configurations of the ring pattern generation systems are bulkier. In diffractive optics, it is possible to alter a function of an element and also integrate multiple functions in a single element. In this paper, we present the design, fabrication and evaluation of single and composite diffractive optical elements for the generation of focused ring patterns. A diffractive toric Fresnel zone lens was designed for parallel beam illumination. This element is compared with other composite diffractive elements capable of generating focused ring patterns. The toric Fresnel zone lens and composite elements were fabricated using electron beam direct writing. The fabricated elements were found to exhibit interesting properties, with the toric lens out-performing the other elements in several areas such as efficiency, focal depth, and ring thickness.
Citations
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TL;DR: In this paper, a simple method for the generation of multi-contour plane curves based on vortex beam illumination of an optical element calculated using the Whittaker integral and parametric curve definition is proposed.
11 citations
Dissertation•
01 Jan 2019
TL;DR: In this paper, a propagador de espectro angular is used to imprime en el plano focal un patron de difraccion, and a metodo for propagación of this propagador is presented.
Abstract: En este trabajo se desarrollo un software que permite modificar la fase y la geometria de un elemento optico difractivo. Adicionalmente se desarrollo un propagador de espectro angular que imprime en el plano focal un patron de difraccion. Una vez formado el patron de difraccion se midio el “Full Width Half Maximun” para obtener la resolucion alcanzada. El propagador no supera la complejidad algoritmica 𝑂(𝑛2). El orden que se seguira es el siguiente: primero se realizara una analisis del estado del arte para observar como se han modificado los elementos opticos difractivos tanto en su fase como en su geometria, luego se procedera a revisar la literatura en cuanto a las alternativas de propagadores que se han implementado para el analisis del campo optico, se revisara la forma de medir el patron de difraccion formado en el plano focal de interes y se concluira con los parametros de fabricacion optimos para el elemento optico difractivo disenado. En la seccion 3 de este trabajo se plantean los objetivos de investigacion, en la seccion 4 se describe la importancia del software de simulacion y diseno desarrollado. En la seccion 5 se realiza un analisis del estado del arte de dos elementos opticos difractivos, la placa zonal de Fresnel y los Photon Sieve. En la seccion 6 se explica en el marco teorico como se construye una placa zonal de Fresnel y cuales son los criterios para su diseno. En esta misma seccion se da una explicacion de como construir un Photon Sieve o tamiz de fotones y sus factores importantes de diseno. Luego se presenta el metodo de propagacion del campo optico, el propagador del espectro angular y se da una breve discusion de porque se eligio este propagador. En la seccion 7 se presentan los materiales y metodos que seran utilizados para desarrollar el software de simulacion para el diseno de elementos opticos difractivos. En la seccion 8 se da una breve discusion y analisis de resultados. En la seccion 9 se describen los modulos que conforman el software, en la seccion 10 se presentan las conclusiones, en la seccion 11 se presentan trabajos futuros y en la ultima seccion la bibliografia.
2 citations
Cites background from "Design, fabrication, and evaluation..."
...En esta, cada espesor de zona viene dado por t = λ nr−1 , donde nr es el índice de refracción del material con el que se fabrica la placa[34]....
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TL;DR: In this paper, a binary Fresnel Zone Axilens (FZA) is designed for the infinite conjugate mode and the phase profile of a refractive axicon is combined with it to generate a composite Diffractive Optical Element (DOE).
Abstract: A binary Fresnel Zone Axilens (FZA) is designed for the infinite conjugate mode and the phase profile of a refractive axicon is combined with it to generate a composite Diffractive Optical Element (DOE). The FZA designed for two focal lengths generates a line focus along the propagation direction extending between the two focal planes. The ring pattern generated by the axicon is focused through this distance and the radius of the ring depends on the propagation distance. Hence, the radius of the focused ring pattern can be tuned, during the design process, within the two focal planes. The integration of the two functions was carried out by shifting the location of zones of FZA with respect to the phase profile of the refractive axicon resulting in a binary composite DOE. The FZAs and axicons were designed for different focal depth values and base angles respectively, in order to achieve different ring radii within the focal depth of each element. The elements were simulated using scalar diffraction formula and their focusing characteristics were analyzed. The DOEs were fabricated using electron beam direct writing and evaluated using a fiber coupled diode laser. The tunable ring patterns generated by the DOEs have prospective applications in microdrilling as well as microfabrication of circular diffractive and refractive optical elements.
References
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TL;DR: The purpose of this paper is to show that when a lens-axicon combination is illuminated by a Gaussian beam, the transverse distribution of the focal ring is also aGaussian distribution.
Abstract: An axicon and a lens are combined to form an optical system producing a ring-shaped pattern. The purpose of this paper is to show that when a lens-axicon combination is illuminated by a Gaussian beam, the transverse distribution of the focal ring is also a Gaussian distribution. The typical width of this distribution was found to be, in the case of the lens-axicon combination, 1.65 times greater than the typical width of the Gaussian beam obtained by focusing the same beam using the lens alone. This focusing system is well suited for the drilling of good quality large diameter holes using a high power laser beam.
144 citations
"Design, fabrication, and evaluation..." refers background or methods in this paper
...Technically, this is similar to illumination of only a section of a lens of the optical configuration discussed in [3]....
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...For applications like optical trapping [1] and micro-drilling [3], it is not necessary to vary the diameter of the ring pattern during the application....
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...Focused ring patterns are useful in a variety of applications like optical trapping [1], corneal surgery [2], micro-drilling [3], etc....
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...The technique to generate focused ring patterns is similar to [3], and combines the functions of an axicon and a FZL....
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TL;DR: Noncontact cornea trephination was performed on human eye-bank eyes by using a Q-switched Er:YAG laser with a axicon-lens combination to demonstrate the possibility of replacing mechanical trephinations in corneal surgery.
Abstract: A new laser beam delivery system using axicon beam shaping has been designed to produce controllable surface ablation as well as trephination for the corneal surgery. Noncontact cornea trephination was performed on human eye-bank eyes by using a Q-switched Er:YAG laser with a axicon-lens combination. The results shows that the uniformity of the trephination along the ring depends on the radial symmetry of the beam. The histological results of the samples show that the damage zone of the laser cut is less than 10 mu m. This demonstrates the possibility of replacing mechanical trephination in corneal surgery. >
68 citations
"Design, fabrication, and evaluation..." refers background in this paper
...Focused ring patterns are useful in a variety of applications like optical trapping [1], corneal surgery [2], micro-drilling [3], etc....
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...However, in corneal surgery [2], it is necessary to generate a focused ring pattern and at the same time have the ability to vary the diameter of the ring pattern in the application plane....
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TL;DR: A novel multifunctional double-layered diffractive optical element based on the fractional Talbot effect that can perform each of the multiple optical functions one by one by shifting the encoding layer.
Abstract: We propose a novel multifunctional double-layered diffractive optical element (DOE) based on the fractional Talbot effect. This DOE consists of two layers: one is the encoding layer, in which multiple sub-DOEs, i.e., multiple optical functions, are encoded; the other is the decoding layer, which is a properly designed Talbot illuminator. This DOE can perform each of the multiple optical functions one by one by shifting the encoding layer. Experimental results demonstrate that this method is efficient. This device should be highly interesting for integrated optics, optical interconnection, secure optical storage, and dynamic optical fiber communications.
23 citations
"Design, fabrication, and evaluation..." refers background in this paper
...It is possible to convert these systems into simpler and lighter ones by replacing the optical components using single and multifunctional diffractive optical components [4]....
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TL;DR: In this paper, the spontaneous formation of identical microspheres (each with diameter 1.1 μm) in conventional single-beam optical tweezers with a usual TEM00 Gaussian beam coupled into a sample chamber having a standing wave geometry with a cover slip and glass slide was studied extensively.
Abstract: (Received 26 October 2011; revised manuscript received 24 January 2012; published 27 March 2012) Microparticle self assembly under the influence of optical forces produced by higher-order optical beams or by projection of a hologram into the trapping volume is well known. In this paper, we report the spontaneous formation of a ring of identical microspheres (each with diameter 1.1 μm) in conventional single-beam optical tweezers with a usual TEM00 Gaussian beam coupled into a sample chamber having a standing wave geometry with a cover slip and glass slide. The effects of different experimental parameters on the ring formation are studied extensively. The experimental observations are backed by theoretical simulations based on a plane wave decomposition of the forward- and backward-propagating Gaussian beams. The ring patterns are shown to be caused due to geometrical aberrations produced by focusing the Gaussian beam using a high-numerical-aperture microscope objective into stratified media. It is found that the thickness of the stratified media and the standing wave geometry itself play a critical role in the formation of stable ring structures. These structures could be used in the study of optical binding, as well as of biological interactions between cells in an optical trap.
23 citations
"Design, fabrication, and evaluation..." refers background in this paper
...For applications like optical trapping [1] and micro-drilling [3], it is not necessary to vary the diameter of the ring pattern during the application....
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...Focused ring patterns are useful in a variety of applications like optical trapping [1], corneal surgery [2], micro-drilling [3], etc....
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22 citations
"Design, fabrication, and evaluation..." refers background in this paper
...Toric lenses are refractive lenses in the shape of a donut, which generate a ring shaped intensity profile at their focal plane [10,11]....
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