Design and Analysis of Flat-Top Beam Produced by Diffractive Optical Element

2015 ◽  
Vol 743 ◽  
pp. 800-807 ◽  
Author(s):  
S.Z. Nie ◽  
J. Yu ◽  
Y. Liu ◽  
Z.W. Fan
Keyword(s):  
Optical Element ◽  
Weighting Factor ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Empirical Constant ◽  
Modified Method ◽  
Input And Output ◽  
Diffractive Efficiency ◽  
The Relationship ◽  
Flat Top Beam

The modified Gerchberg-Saxton (G-S) methods of diffractive optical elements are presented for converting a Gaussian beam into a flat-top beam. The sample points of the input and output planes are discussed based on the sampling principle. The relationship between weighting factor, empirical constant, diffractive efficiency, and intensity uniformity is investigated. The simulation results of different modified methods are calculated when the incident beams are the same. The results show that the intensity uniformity of the output flat-top beam is the best when using the ST modified method.

scholarly journals A theoretical framework for general design of two-materials composed diffractive fresnel lens

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ming-Yen Lin ◽  
Chih-Hao Chuang ◽  
Tzu-An Chou ◽  
Chien-Yu Chen
Keyword(s):  
Optical Materials ◽  
Diffraction Theory ◽  
Fresnel Lens ◽  
Theoretical Framework ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
General Design ◽  
Diffractive Efficiency ◽  
The Relationship ◽  
Partial Dispersion

AbstractNear 100% of diffractive efficiency for diffractive optical elements (DOEs) is one of the most required optical performances in broadband imaging applications. Of all flat DOEs, none seems to interest researchers as much as Two-Materials Composed Diffractive Fresnel Lens (TM-DFL) among the most promising flat DOEs. An approach of the near 100% of diffractive efficiency for TM-DFL once developed to determine the design rules mainly takes the advantage of numerical computation by methods of mapping and fitting. Despite a curved line of near 100% of diffractive efficiency can be generated in the Abbe and partial dispersion diagram, it is not able to analytically elaborate the relationship between two optical materials that compose the TM-DFL. Here, we present a theoretical framework, based on the fundaments of Cauchy's equation, Abbe number, partial dispersion, and the diffraction theory of Fresnel lens, for obtaining a general design formalism, so to perform the perfect material matching between two different optical materials for achieving the near 100% of diffractive efficiency for TM-DFL in the broadband imaging applications.

scholarly journals Nanooptical elements for visual verification

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Goncharsky ◽  
Anton Goncharsky ◽  
Dmitry Melnik ◽  
Svyatoslav Durlevich
Keyword(s):  
Electron Beam ◽  
Electron Beam Lithography ◽  
Mass Production ◽  
Optical Element ◽  
Visual Image ◽  
Zero Order ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Standard Equipment ◽  
Diffractive Element

AbstractThis paper focuses on the development of flat diffractive optical elements (DOEs) for protecting banknotes, documents, plastic cards, and securities against counterfeiting. A DOE is a flat diffractive element whose microrelief, when illuminated by white light, forms a visual image consisting of several symbols (digits or letters), which move across the optical element when tilted. The images formed by these elements are asymmetric with respect to the zero order. To form these images, the microrelief of a DOE must itself be asymmetric. The microrelief has a depth of ~ 0.3 microns and is shaped with an accuracy of ~ 10–15 nm using electron-beam lithography. The DOEs developed in this work are securely protected against counterfeiting and can be replicated hundreds of millions of times using standard equipment meant for the mass production of relief holograms.

scholarly journals On a problem of the synthesis of binary nano-optical elements

2016 ◽  
pp. 415-424
Author(s):  
А.А. Гончарский ◽  
С.Ю. Серёжников
Keyword(s):  
Electron Beam ◽  
Augmented Reality ◽  
Electron Beam Lithography ◽  
Optical Element ◽  
Diffractive Optical Elements ◽  
Partial Loss ◽  
Optical Elements ◽  
Optical Images ◽  
Augmented Reality Technology ◽  
Security Label

В рамках широко распространенной технологии Augmented Reality обсуждается возможность контроля подлинности защитных оптических меток на основе бинарных нанооптических элементов. С помощью смартфона фотографируют изображение защитной метки. Полученное изображение интерпретируется как дифракционный оптический элемент. В приближении Френеля рассчитывают изображение, формируемое дифракционным оптическим элементом, которое используют для идентификации подлинности защитной метки. Защитная метка представляет собой фазовый оптический элемент, глубина микрорельефа которого не превышает 0.5 мкм. Нанооптические элементы изготавливаются с помощью электроннолучевой литографии. Разработанные нанооптические элементы устойчивы к частичному повреждению микрорельефа и могут быть использованы для идентификации банкнот, документов и др. This paper deals with optical security label identification technology as a part of augmented reality technology. Security labels are based on binary nanooptical elements and are photographed using a smartphone. Photographed images are interpreted as diffractive optical elements. Optical images formed by these diffractive elements are computed using the Fresnel approximation. These images are used to identify the security labels. A security label consists of a phase optical element whose microrelief height is of no more than 0.5 $\mu$m. Nanooptical elements are manufactured using electron-beam lithography. The optical security labels are resistant against microrelief damages and can withstand partial loss of an image. The optical elements developed can be used to protect and identify banknotes, documents, etc.

scholarly journals Modified Method of Increasing of Reconstruction Quality of Diffractive Optical Elements Displayed with LC SLM

2015 ◽  
Vol 73 ◽  
pp. 287-294
Author(s):  
V.V. Krasnov ◽  
P.A. Cheremkhin ◽  
I. Yu. Erkin ◽  
N.N. Evtikhiev ◽  
R.S. Starikov ◽  
...  
Keyword(s):  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Modified Method ◽  
Reconstruction Quality

Laser Power Characterization Method for Fabrication of Centrosymmetric CR-DOEs Mask

2008 ◽  
Vol 53-54 ◽  
pp. 337-342
Author(s):  
Duo Shu Wang ◽  
Chong Tai Luo ◽  
Tao Chen ◽  
Yu Qing Xiong ◽  
Hong Kai Liu ◽  
...  
Keyword(s):  
Laser Power ◽  
Low Cost ◽  
Chromatic Aberration ◽  
Diffractive Optical Elements ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Optical Elements ◽  
Short Period ◽  
Diffractive Efficiency ◽  
Mask Fabrication

With high diffractive efficiency, Continuous Relief Diffractive Optical Elements (CR-DOE) can be used to eliminate chromatic aberration, partial aberration and simplify optical system. The technology for CR-DOE with Laser Direct Writing method has advantages of simple process, short period and low cost. The paper studied on the characterization method of laser power for the technology. The principle of mask fabrication of CR-DOE by Laser Direct Writing is described in the paper. The relations between microstructure depth and laser power, exposing position radius and laser power were studied. The results showed that microstructure depth changes in direct ratio to laser power and laser power should change in direct to exposing position radius while several same depth microstructures were fabricated at different radius. At the end, the paper gave the charactering method and also fabricated the mask of a kind of centrosymmetric continuous relief diffractive focus lens with the method.

scholarly journals An approach to realisation of a Radial Phase mask using 3-D printing in transparent PLA

2017 ◽  
Vol 16 (1) ◽  
pp. 22-29
Author(s):  
Simran Agarwal ◽  
Romuald Jolivot ◽  
Waleed S. Mohammed
Keyword(s):  
Iterative Algorithm ◽  
Processing Time ◽  
Optical Element ◽  
Beam Shaping ◽  
Beam Profile ◽  
Phase Mask ◽  
Experimental Setup ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Radial Phase

In the recent years, many different techniques and algorithms have been devised to design diffractive optical elements (DOE’s) for the purpose of beam shaping. This paper demonstrates an approach to realise a 3-D printed radial phase mask to be used in beam shaping to achieve a beam profile closer to the flattop. An iterative algorithm approach is employed to simulate the phase masks in greyscale and subsequently into STL format. These 3-D printed masks are used as an optical element and characterised using an experimental setup. The images of the light after the characterisation are examined and compared with the simulated results. Therefore, this method reduces the complexity as 3-D printing the masks eliminates the need for fabrication, processing time and number of components necessary to obtain a flattop beam profile.

scholarly journals Computer synthesis of diffractive optical elements for forming 3D images

2017 ◽  
pp. 11-19
Author(s):  
С.Р. Дурлевич
Keyword(s):  
Optical Element ◽  
Diffractive Optical Element ◽  
Diffractive Optical Elements ◽  
Optimal Parameters ◽  
Optical Elements ◽  
Standard Equipment ◽  
3D Images ◽  
Security Feature ◽  
Diffractive Element ◽  
Visual Security

Предложен метод расчета и синтеза микрорельефа дифракционного оптического элемента, формирующего новый визуальный защитный признак - эффект смены одного 3D-изображения на другое 3D-изображение при повороте дифракционного оптического элемента на 90 градусов. Разработаны эффективные алгоритмы расчета микрорельефа дифракционного оптического элемента. Методами математического моделирования определены оптимальные параметры дифракционного оптического элемента. С помощью электронно-лучевой технологии изготовлены образцы оптических защитных элементов, формирующих визуальный эффект смены 3D-изображений при освещении оптического элемента белым светом. Разработанные оптические элементы могут тиражироваться с помощью стандартного оборудования, используемого для изготовления защитных голограмм. Новый защитный признак легко контролируется визуально, надежно защищен от подделки и предназначен для защиты банкнот, документов, идентификационных карт и др. A method is proposed to compute and synthesize the microrelief of a diffractive optical element to produce a new visual security feature: alternation of two 3D color images when the diffractive element is rotated by 90 degrees. Effective algorithms for computing the micro-relief of an optical element are developed. Optimal parameters of the diffractive optical element are determined using methods of mathematical modeling. Sample optical security elements that produce 3D to 3D visual switch effect when illuminated by white light were manufactured using the electron-beam lithography. The optical elements developed can be replicated using a standard equipment employed for manufacturing security holograms. The new optical security feature is easy to control visually, safely protected against counterfeit, and designed to protect banknotes, documents, ID cards, etc.

scholarly journals 3D printable diffractive optical elements by liquid immersion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Reut Orange-Kedem ◽  
Elias Nehme ◽  
Lucien E. Weiss ◽  
Boris Ferdman ◽  
Onit Alalouf ◽  
...  
Keyword(s):  
Incident Light ◽  
Scale Up ◽  
Optical Element ◽  
Diffractive Optical Elements ◽  
Relevant Feature ◽  
Experimental Conditions ◽  
Optical Elements ◽  
Point Spread ◽  
Spread Function ◽  
Liquid Immersion

AbstractDiffractive optical elements (DOEs) are used to shape the wavefront of incident light. This can be used to generate practically any pattern of interest, albeit with varying efficiency. A fundamental challenge associated with DOEs comes from the nanoscale-precision requirements for their fabrication. Here we demonstrate a method to controllably scale up the relevant feature dimensions of a device from tens-of-nanometers to tens-of-microns by immersing the DOEs in a near-index-matched solution. This makes it possible to utilize modern 3D-printing technologies for fabrication, thereby significantly simplifying the production of DOEs and decreasing costs by orders of magnitude, without hindering performance. We demonstrate the tunability of our design for varying experimental conditions, and the suitability of this approach to ultrasensitive applications by localizing the 3D positions of single molecules in cells using our microscale fabricated optical element to modify the point-spread-function (PSF) of a microscope.

scholarly journals Neural-network based approach to optimize THz computer generated holograms

2021 ◽  
Vol 13 (4) ◽  
pp. 88
Author(s):  
Mateusz Surma ◽  
Mateusz Kaluza ◽  
Patrycja Czerwińska ◽  
Paweł Komorowski ◽  
Agnieszka Siemion
Keyword(s):  
Neural Network ◽  
Optical Element ◽  
Computational Design ◽  
Additive Manufacture ◽  
Diffractive Optical Elements ◽  
Terahertz Waves ◽  
Neural Network Approach ◽  
Optical Elements ◽  
Industrial Sectors ◽  
Terahertz Technology

Terahertz (THz) optics often encounters the problem of small f number values (elements have relatively small diameters comparing to focal lengths). The need to redirect the THz beam out of the optical axis or form particular intensity distributions resulted in the application of iterative holographic methods to design THz diffractive elements. Elements working on-axis do not encounter significant improvement while using iterative holographic methods, however, for more complicated distributions the difference becomes meaningful. Here, we propose a totally different approach to design THz holograms, utilizing a neural network based algorithm, suitable also for complicated distributions. Full Text: PDF ReferencesY. Tao, A. Fitzgerald and V. Wallace, "Non-Contact, Non-Destructive Testing in Various Industrial Sectors with Terahertz Technology", Sensors, 20(3), 712 (2020). CrossRef J. O'Hara, S. Ekin, W. Choi and I. Song, "A Perspective on Terahertz Next-Generation Wireless Communications", Technologies, 7(2), 43 (2019). CrossRef L. Yu et al., "The medical application of terahertz technology in non-invasive detection of cells and tissues: opportunities and challenges", RSC Advances, 9(17), 9354 (2019). CrossRef A. Siemion, "The Magic of Optics—An Overview of Recent Advanced Terahertz Diffractive Optical Elements", Sensors, 21(1), 100 (2020). CrossRef A. Siemion, "Terahertz Diffractive Optics—Smart Control over Radiation", J. Infrared Millim. Terahertz Waves, 40(5), 477 (2019). CrossRef M. Surma, I. Ducin, P. Zagrajek and A. Siemion, "Sub-Terahertz Computer Generated Hologram with Two Image Planes", Appl. Sci., 9(4), 659 (2019). CrossRef S. Banerji and B.Sensale-Rodriguez, "A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements", Sci. Rep., 9(1), 5801 (2019). CrossRef J. Sun and F. Hu, "Three-dimensional printing technologies for terahertz applications: A review", Int. J. RF. Microw. C. E., 30(1) (2020). CrossRef E. Castro-Camus, M. Koch and A. I. Hernandez-Serrano, "Additive manufacture of photonic components for the terahertz band", J. Appl. Phys., 127(21), 210901 (2020). CrossRef https://community.wolfram.com/groups/-/m/t/2028026?p_%20479%20p_auth=blBtLb5d DirectLink P. Komorowski, et al., "Three-focal-spot terahertz diffractive optical element-iterative design and neural network approach", Opt. Express, 29(7), 11243-11253 (2021) CrossRef M. Sypek, "Light propagation in the Fresnel region. New numerical approach", Opt. Commun., 116(1-3), 43 (1995). CrossRef

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