Diffractive optical elements. Wolfe, Ignacio Moreno, and Don M. Because of their flexibility in controlling the wave front of incident light, DOE can implement various functions that conventional refractive optical elements typically cannot. A DOE is identified that superresolves the focal spot by 34% and maintains the sidelobes below 50% of Jan 1, 2022 · Diffractive optical elements (DOE) are widely used in various optical systems due to their special negative dispersion characteristics. The basic concepts of structure design together with Diffractive optical elements (DOEs) are optical components consisting of microscopic phase structures in a transparent material . The arrangement of the spots is not limited to Aug 20, 2020 · Diffractive optical elements have several advantages over traditional refractive optics: DOE are flat, thin and lightweight making them the perfect solution in systems where compactness is valued. The gray-scale mask is employed in an optical aligner to expose an analog photoresist on any environmentally durable substrate, e. SPIE 10774, Optical T echnologies in T elecommunications 2017, 107740O (6. In this letter, the authors propose and demonstrate the use of the two-photon polymerization method for fabricating three-dimensional diffractive optical elements of continuous The range of validity of the scalar diffraction analysis is quantified for the case of two-dimensionally-periodic diffractive optical elements (crossed gratings). Coherent DOEs are built for use in demanding industrial applications – high-power laser welding, PCB drilling, glass cutting, solar cell Jul 20, 2020 · Diffractive optical elements (DOEs) are widely applied as compact solutions to generate desired optical patterns in the far field by wavefront shaping. Acrylate-on-polymer elements, the diffractive layer is created by UV curing on a polymer substrate. Appearance of DOE and its surface microstructure. It appears better able to locate the global minimum compared with a canonical GA. Characteristics that are concentrated on are a high diffraction efficiency and a large signal-to-noise ratio. Light incident on a grating is diffracted following the grating equation: (1) $$ m \lambda = d \left ( \sin {\alpha} + \sin {\beta} \right) $$. June 2018); doi: 10. Here, we demonstrate broadband DOEs We present a method for reproducing diffractive optical elements in quantity. Existing solutions require multiple components assembly, which is difficult to implement in an integrated system. Jeffrey A. Schematics of the optical elements are depicted in the bottom left corner together with Feb 12, 2007 · Generation of continuous gray levels in three-dimensional diffractive optical elements has remained a challenge with the current semiconductor microfabrication method. , adding a lens' phase to the designed Fraunhofer-type DOEs, are used for the design. Feb 10, 2021 · Upon annealing at 400 °C, the deposited ZrO 2 structures have excellent optical transparency across a wide wavelength range (0. Davis, Everett D. See full list on rp-photonics. That way, it is possible to shape or split laser beams with very high efficiencies. This enables you to efficiently shape light and consequently improve the overall performance and flexibility of your products. 回折光学素子の原理」に詳述）を利用した光学素子です。光学素子として、従来は、レンズやプリズムなど、光の屈折現象を利用したものが多く使われてきました。しかし、近年では微細加工技術の進展や、小型軽量化・薄型 Feb 20, 2024 · Diffractive surfaces. Jul 17, 2019 · Diffractive optical elements and subwavelength dielectric–metallic elements (metasurfaces) are important building blocks in science and technology 1,2,3,4,5,6. However, despite considerable efforts to develop different technologies for DOEs, they still remain highly underutilized in broadband imaging system. This hybrid algorithm incorporates advantages of both genetic algorithm (GA) and local search techniques. However, such elements introduce severe Examples of such diffractive optical elements are shown in Figs. They enable the design of compact and lightweight optical components that can perform the same function as their refractive counterparts. Commercially available DOEs include lenses, arrays of lenses, or holograms (so-called kinoforms [ 2 ]) that project specified patterns, such as lines, crosshairs, or dot arrays. Kazanskiy, "Modeling diffractive optics elements and devices," Proc. The optimization decreases the loss of diffraction efficiency related to convolution of a desired phase profile with This paper presents a novel approach to optimizing the design of phase-only computer-generated holograms (CGH) for the creation of binary images in an optical Fourier transform system. We developed the multi-layer diffractive optical elements to operate with visible wavelength region. Nov 19, 2020 · Diffractive Optical Elements (DOEs), sometimes referred to as digital diffractive optics, are phase relief elements that uses micro-structures to alter the phase of the light propagated through them, and thus manipulate it in various ways to create shapes and light patterns that are either impossible to achieve in different methods using refractive optics, or require very complex, bulky and Apr 15, 2020 · Diffractive optics have increasingly caught the attention of the scientific community. Considering the rapidity and validity of the design method, we propose a fast method for designing broadband achromatic diffractive optical elements. This is important for high-power laser fiber coupling, where hot spots lead to failure. However, only the intensity distribution of the selected sampling points is controlled by these optimization algorithms. Design techniques for diffractive optic in the two theoretical design areas, the scalar and resonance domains, and the dominant methods of fabrications are described. The DOE was designed based on finite-element method simulations, fabricated using micromachining technology, and characterized for despeckle efficiency. By altering the microstructures, it is possible for a diffractive optical element to produce almost any beam intensity profile or beam shape to meet application requirements. Here we introduce nanocomposites as a material platform that allows for Dec 8, 2022 · Diffractive optical elements (DOEs) play an important role in modern optical applications such as spectral and imaging systems, but it is challenging to balance the diffraction efficiency with the working bandwidth. A diffractive surface provides unique advantages for the optical designer, enabling lens systems to be simplified. The diffracting object or aperture Diffractive optical elements (DOEs) are passive devices that redirect and focus light through the division and mutual interference of a propagating electromagnetic wave. Here, we propose a geometrical-optics method for calculating the eikonal function of the light field providing the Diffractive optical elements (DOEs) shape and split laser beams in an energy-efficient manner. However, traditional methods to achieve varying thicknesses of structures for DOEs are tedious, requiring multiple aligned Dec 22, 2021 · Thin, lightweight micro-diffractive optical elements (M-DOEs) are of great significance to integrated optics. Here we achieved the structured light patterns of a pseudorandom dot array by a single diffractive optical element. Top-hat and arbitrary pattern DOE beam shapers were numerically optimized using an iterative Fourier transform algorithm (IFTA). Fabrication of multiple arbitrary diffractive optical elements (DOEs) on multiple curved surfaces is always a challenge; here we propose an effective optimization method to fabricate complicated DOEs on several curved surfaces at the same time. Sample cases investigated here include the optimization design of binary-phase Dammann Apr 6, 2023 · On the other hand, these systems still require the use of optical relay systems and dispersive optical elements such as prisms, and diffractive elements, resulting in relatively bulky form factors HOLOEYE offers diffractive elements fabricated by one of the following options: Bulk polymer elements, the substrate and a diffractive micro-relief surface are created by compression molding using materials like polycarbonate, PMMA, or Topas ®. Three canonical classes of two-dimensionally-periodic grating structures are analyzed by using the rigorous coupled-wave analysis as well as the scalar diffraction analysis. When size or weight of the optical system is crucial, DOEs provide substantial advantages and can be used to design an aberration-minimizing compact imaging system thinner and lighter Oct 5, 2018 · A diffractive optical element (DOE) uses thin micro-structure patterns to alter the phase of the light that is propagated through it. It is hoped a better understanding of fabrication errors will allow elements with greater tolerance to be designed. Download full size. Diffraction is the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. Aug 12, 1998 · Compared with other kinds of diffractive optical elements (DOEs), the harmonic diffractive optical element (HDOE) is analyzed, and some important results including its dispersion are deduced and presented in this paper. DOE are passive components, and depending on the substrate material can be extremely robust, thus preform perfectly over time in any system and Diffractive Optical Elements (DOE) Transform Gaussian laser beams into other intensity distributions to achieve optimal results in a variety of materials processing applications with Coherent DOEs. By engineering the diffraction, DOE can split, homogenize, and focus laser beams. Our selection of diffractive optics includes blazed, slanted, 1D and 2D Diffractive optical elements (DOEs) shape and split laser beams in an energy-efficient manner. Holo/Or is a leading company that designs and manufactures DOEs for different wavelengths and laser powers. First we design phase distribution to modulate complicated three-dimensional (3D) intensity Encoding complex amplitude information onto phase-only diffractive optical elements using binary phase Nyquist gratings. In all cases the scalar-analysis diffraction efficiencies We propose a novel multifunctional double-layered diffractive optical element (DOE) based on the fractional Talbot effect. , multiple optical functions, are encoded; the other is the decoding layer, which is a properly designed Talbot illuminator. Sep 12, 2023 · Diffractive optical elements (DOEs) enable highly complex shaping of light by a single, compact, optical component. The most frequently-used design method for diffractive optical elements (DOE) is scalar diffraction theory, but it is unsuitable for the design of sub-wavelength DOE with large diffraction angles. The design process includes spatial Fourier filtering that results in a smooth DOE phase profile, for converting a Gaussian incident beam with arbitrary phase distribution (random/spherical) into a flat-top beam with Holo/Or production – an overview of more than 30 years as a leading diffractive optical element manufacturer. We propose a novel multifunctional double-layered diffractive optical element (DOE) based on the fractional Talbot effect. This is because dispersion causes the diffraction efficiency to decrease as a function of the wavelength. Dec 20, 2023 · Diffractive optical elements (DOEs) are typically designed to manipulate the phase of light as it passes through the element to produce the desired optical effect. [10-12] Abstract. Summary. Optimization begins by selecting an image pixel with a temporal change in amplitude. The wideband-wavelength diffractive optical element (WBDOE) consists of two aligned DOE’s. In this paper, a hybrid algorithm which combines particle swarm optimization with a Jan 11, 2021 · Diffractive deep neural networks (D 2 NNs) form such an optical computing framework that benefits from deep learning-based design of successive diffractive layers to all-optically process Diffractive Optical Elements (DOEs) exist for a large range of applications. ). If so, the output beam array becomes an array of focused spots at a certain distance behind the lens. This book covers all aspects of the design of diffractive lens systems, and is an essential reference for incorporating diffractive optical elements into imaging systems. e. Experiments using a DOE with two gratings have indicated that the speckle was suppressed to 50% Jan 1, 2019 · Diffractive optical elements (DOE) are thin phase or amplitude elements that operate by means of diffraction to produce arbitrary distributions of light. November/01/2021. Opt. Diffraction efficiency results for a wide range of zone widths are presented to provide the reader with a baseline of expected performance for replicated visible and near-infrared diffractive optical elements. Optical variable devices (OVDs) are another type of diffractive optical elements for which 3D electron beam lithography is the manufacturing method of choice. 08% and a second-order mode loss of 48. The high power diffractive optical element market is experiencing a major boom in recent years, as DOE powered applications such as aesthetic laser treatments, laser glass cutting, laser micro-machining and laser Dec 1, 1997 · Abstract. DOEs are extensively used as beam shaping elements, lenses and other Jul 1, 2015 · Diffractive optical elements are attractive for various optical applications due to their versatility in function and inherent compactness. m is an integer value describing the diffraction (or spectral) order, λ is the light’s wavelength, d is the spacing between grooves on the grating, α is the incident angle of light, and β is the . Classical diffractive optics are 2D diffractive optical elements (DOEs) and computer-generated holograms Dec 26, 2020 · Diffractive optical elements are well known for being not only flat but also lightweight, and are characterised by low attenuation. Their compact dimensions, lightweight nature, and compatibility with diverse materials render DOEs as prime candidates for integration into various optical systems We would like to show you a description here but the site won’t allow us. This capability makes DOEs attractive in a variety of applications 1, including NIL Technology is specialized in diffractive optical elements (DOEs). 3mm) were patterned We formulate and apply an efficient finite-difference time-domain algorithm to the analysis of axially symmetric diffractive optical elements. Compared to the ROEs, the DOEs have been widely used for Sep 1, 2003 · 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. Direct and indirect methods, i. The method is compatible with VLSI microfabrication techniques and involves generating a gray-scale mask. (a) The l th-order of the CVB can be decomposed into a superposition of two OAMs with opposite circular polarizations. The differences among the phase modulations result from the differences among the effective indices exhibited in the subwavelength structures with various filling factors and surface profiles, and the phase retardations are obtained by the relief depth of the structures. A diffractive surface-based free-space optical processor is spatially engineered at the wavelength scale ( λ /2 or larger) to generate a desired spatial distribution of the The use of diffractive optical elements (DOEs) in broadband optical systems can often significantly reduce their size or enhance their performance but is mostly prevented by stray light in unwanted diffraction orders. Of all flat DOEs, none seems to Nov 16, 2019 · Robust designs of single-diffractive optical elements (DOEs) on forming flat-top beams with extended depth of focus for different wavelengths and beam sizes are presented. A few examples of output beam patterns are illustrated below. With a designed vectorial diffractive unit cell, each polarization state will be modulated with different phase shift with respect to its polarization, and the unit We demonstrate the design, fabrication, and experimental characterization of near-field binary phase transmission diffractive optical elements (DOEs) in single crystal diamond. We discuss aspects relating to minimizing numerical dispersion in the incident field, application of absorbing boundary conditions in the radial direction, convergence to a steady state, and propagation of the steady-state electromagnetic fields from We propose a genetic local search algorithm (GLSA) for the optimization design of diffractive optical elements (DOE’s). , glass, quartz, semiconductor, or metal, one exposure for each diffractive Jun 6, 2018 · N. Diffractive optical elements (DOEs), which are relatively new additions to the toolbox of optical engineering, can function as lenses, gratings, prisms, aspherics, and many other types of optical element. You can implement a wide range of applications with minimal light loss – examples of diffractive microoptics can be found in production facilities for laser material processing, in medical laser treatments and diagnostic instruments, in areas such as lighting, printing technologies and lithography Mar 1, 2020 · Diffractive optical elements (DOEs) exhibit special dispersion and thermal properties that considerably enhance their usefulness in several applications [1], [2]. com Learn how DOEs can manipulate light for various applications, such as laser material processing and aesthetic treatments. Polarization-multiplexed phase-only diffractive optical elements with subwavelength structures are proposed and fabricated. We commemorate the 75th anniversary of DOEs by providing a comprehensive overview and forward-looking perspective on the significant milestones, recent advancements, and promising domains within the realms of DOEs. 1 1 17/12 In this Letter, we propose a motionless diffractive optical element (DOE) for speckle reduction. Diffractive optical elements (DOEs) for beam shaping are widely used in many fields, and there are many kinds of optimization algorithms to design the DOEs for beam shaping. The design process and simulation of the MLDOEs with regard to an example for visible Sep 12, 2022 · Abstract. The design of this diffractive element is shown for a square, flat-topped fundamental mode. A diffraction pattern of a red laser beam projected onto a plate after passing through a small circular aperture in another plate. An overview of the recently invented terahertz optical structures based on diffraction design is presented. The Pt/Co stacks are irradiated by Ar+ ions at selected areas so that the perpendicular anisotropy is spatially modulated and the DOEs can be tuned by an external magnetic field through the magnetooptical effect. The idea consists of serially combining a few elementary diffractive elements that might be spatially separated. The indirect method can reduce the calculation time by approximately half without loss of design accuracy. Fresnel-type diffractive optical elements (DOEs) for general beam shaping of monochromatic, spatially incoherent light are demonstrated. Feb 8, 2024 · 回折光学素子（DOE：Diffractive Optical Element）とは、光の回折現象（「2. A procedure to calculate a highly quantized, blazed phase structure is presented. The mathematical relationship between the substrate material selection for dual-band MLDOE and polychromatic integral diffraction efficiency (PIDE) is deduced in the oblique incident situation, and further, a method for optimal selection of A new method for eliminating the chromatic aberration of a diffractive optical element (DOE) for wideband wavelengths is presented. Kazanskiy. Topics include paraxial imaging theory, aberration theory Jul 29, 2021 · Near 100% of diffractive efficiency for diffractive optical elements (DOEs) is one of the most required optical performances in broadband imaging applications. One or some of these elements should Diffractive (or Binary) Optics Applications Narrowband (Laser) Optics Wide-field Imaging Fourier Transform Lenses Collimation & Beam Expansion F-Theta Scan Lenses Anamorphic (Cylindrical Elements) Microlens arrays --Hartmann Sensors, Laser Diodes and Detector Arrays Optical Interconnects Null Optics for Interferometric Testing Broadband Optical The silicon-based diffractive optical elements, conventional Fresnel zone plate (ZP), Fibonacci lens (F), Bessel axicon (B), and Airy zone plate (A), are placed in the positions indicated by DOE 1 $_{1}$ and DOE 2 $_{2}$ in various investigation scenarios. The use of different dispersive materials for the two DOE’s eliminates chromatic aberration. Jun 12, 2021 · The integration of diffractive optical elements (DOEs) into a broadband optical system can often allow for increasing the system’s performance, reducing its size, or its complexity. Usually DOEs are obtained by combining lithographic techniques and etching in order to achieve pre-determined phase patterns. Application to the fabrication of surface-relief diffractive optical elements is presented, and theoretical predictions Apr 1, 2015 · This, in turn, is driving much more strict requirements, such as higher diffractive efficiency of the diffractive optical elements (DOEs) used in the OAI system. Such thin surfaces offer Dec 4, 2023 · Figure 37. Jul 20, 2015 · A two-dimensional DOE for beam shaping is designed, and the simulation results and the experimental results demonstrate the good performance of this algorithm. Diffractive optical elements 75 years: from micro-optics to metasurfaces. An introduction to the design and fabrication of diffractive optical elements is presented. The large chromatic dispersion effects of DOE resulting from the spectral bandwidth of femtosecond pulses can be reduced with the appropriate DOE focal length and the proper distance between the DOE and the Vectorial diffractive unit cell and optical element design. The dot array can be applied to achieve three-dimensional imaging. The laser cavity has a theoretical fundamental mode loss of only 0. Some examples of DOEs include diffraction gratings, Fresnel zone lenses [1], and diffractive axicons [2] and so on. First, the pseudorandom dot array was generated by the proposed improved encoding methods, which are an improved formula-method-based encoding algorithm and an improved enumeration-method-based encoding algorithm Abstract. The core issue is controlling the broadband dispersion of all phase units to achieve achromatic 2π-phase modulation in the broadband domain. This DOE consists of two layers: one is the encoding layer, in which multiple sub-DOEs, i. 5a and 5b. This DOE can perform each of the multiple optical Apr 21, 2023 · We report a novel type of magnetically tunable diffractive optical element (DOE) based on ultrathin ferromagnetic (FM) Pt/Co stacks. Diffractive optical elements play a crucial role in the miniaturization of the optical systems, especially in correcting achromatic aberration. This technology enables many functions and light manipulations which are not feasible Sep 16, 2016 · Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. Sputtered Al was patterned via contact photolithography. Indeed for binary element which consist of two phase levels (0 and π) the diffraction efficiency is around Aug 24, 2021 · A pair of adjacent transmissive diffractive optical elements (DOEs) forms a combined DOE with tunable optical properties, as, for example, a diffractive lens with an adjustable focal length. Cottrell OSA Continuum 4(3) 896-910 (2021) Apr 3, 2023 · Diffractive elements have a great impact on THz optical systems because their manufacturing is very simple in comparison with any other range of radiation (infrared, visible, ultraviolet, etc. Those micro-structures, once properly designed, can manipulate the light to almost any desired intensity profile or shape. N. Optimization method of manufacturing for diamond turning soft-brittle materials’ harmonic diffractive optical elements Xiang Gao, Changxi Xue, Yang Chao, and Yue Liu Appl. A particle-swarm optimization (PSO) algorithm was developed for designing binary-phase-only diffractive optical elements (DOEs) that superresolve the axially focused point-spread function. The calculation techniques are based on iterative Fourier-transform algorithms. Its inherent advantages and characteristics are analyzed and concluded, and then several applications including imaging in the wide wavelength band, multicolor optical Fourier Diffractive optical element (DOE) DOE has micro structured surface relief patterns which cause light diffraction. Therefore, it is a effective way to correct chromatic aberrations by using DOE in broadband or multi-band imaging systems. Based on this concept, a diffraction Feb 1, 2013 · Beam shaping has been widely used in inertial confinement fusion [1], excimer laser lithography [2], [3], fiber coupling laser diode array [4], laser welding [5], etc. We then fabricate diffractive optical elements, such as binary phase diffraction gratings, that show efficient diffractive behavior and A diffractive laser cavity mirror is described that can customize the amplitude and phase of a laser mode. Such lenses, used for instance in lighthouses, become handy to reduce space and weight constraints related to standard refractive lenses. Since the design algorithms to optimize DOEs’ phase profile are improved, the fabrication process becomes the main limiting factor leading to energy loss. Based on the direct binary search Jan 24, 2022 · Other diffractive optical elements (DOEs) of common use are Fresnel lenses, in practice, cylindrically symmetric gratings optimized to focus collimated light at a design distance. 60 (1) 162-171 (2021) As design algorithms for diffractive optical elements improve, the limiting factor becomes the fabrication process. However, traditional DOEs illuminated by a multicolor mixed white LED would result into diffraction patterns with unequal sizes. What we believe to be a new method for designing multilayer diffractive optical elements (MLDOEs) for wideband with consideration of polychromatic integral diffraction efficiency (PIDE) is presented. 2%, resulting in high modal discrimination. Diffractive Optical Elements (DOE) are manufactured to have microstructure patterns that alter and control the phase of transmitted laser light. In different spectral ranges, they provide better efficiency than commonly used refractive lenses. in binary DOE fabricated in polycrystalline diamond, designed as a fan-out element (16-way beamsplitter). However, the narrow working bandwidth of M-DOEs allows them to operate only at specific wavelengths. The design and simulation of a WBDOE for the visible spectrum are presented. We make diffractive optics that are customized to your specific needs. Theoretical and experimental examples are given in each section. The principle of the multi-layer diffractive optical elements and application to photographic lens system, EF400mm F4 DO IS USM, is reported. OVDs change their optical appearance depending on illumination and viewing angle (hence the name). Laser beam can be controlled using DOE. The fabricated mirror is tested in a Nd:YAG Dec 1, 1997 · Abstract. The intensity distribution of other We present a procedure for the characterization and the linearization of the photoresist response to UV exposure for application to the gray-scale fabrication of diffractive optical elements. They consist of microscopic structures of varying heights to control the phase of either reflected or transmitted light. You can implement a wide range of applications with minimal light loss – examples of diffractive microoptics can be found in production facilities for laser material processing, in medical laser treatments and diagnostic instruments, in areas such as lighting, printing technologies and lithography A Diffractive Beam Splitter splits the incident laser beam into a 1-dimensional or 2-dimensional array of beams. In this paper, we propose a hybrid iterative design method, which effectively utilizes the large-scale global optimization characteristics of scalar diffraction theory and the accuracy of the A new configuration of diffractive optical elements is presented that takes full advantage of the progress made in the field of fixed elements and also offers the possibility of programmability. 4 days ago · Diffractive Optical Elements (DOEs) are indispensable tools across numerous technological domains due to their capacity to manipulate light with sophistication and versatility. Two different design examples are Diffractive optical elements (DOEs) can be used in the optical transmitter system to shape the diffraction patterns into polygons. Typically diffractive beam splitters are used in combination with a focusing lens. 3-10 μm), a high refractive index (n = 1. L. Hybrid methods combining the geometrical-optics and diffraction-theory methods enable designing diffractive optical elements (DOEs) with high performance due to the suppression of stray light and speckles and, at the same time, with a regular and fabrication-friendly microrelief. Stagnation problems are discussed, and methods to overcome them are described. Published Articles. This is in contrast to refractive elements, which redirect and focus light through variations in indices of refraction. Beam shaping usually can be realized either by refractive optical elements (ROEs) or diffractive optical elements (DOEs). In addition, a new method for analyzing diffractive surface structures is presented. The method is based on vector diffraction theory to ensure solutions are valid under high-NA conditions. Typically formed in a film of only a few microns thickness, a DOE may be fabricated on an arbitrarily-shaped substrate. We model seven different fan-out gratings applying misetch, misalignment Diffractive optical elements (DOEs) are optical components that use the diffractive properties of engraved microstructures to transform the incoming beam into the desired light distribution, using the periodicity of the structure or lack thereof to create discrete (beam splitters) or continuous patterns (beam shapers, diffusers) respectively. g. A mid-wave infrared (MWIR)/long-wave infrared (LWIR) dual-band zoom lens design with multilayer diffractive optical elements (MLDOEs) is presented. The modulated image function undergoes an inverse Fourier transform followed by the imposition of a CGH constraint and the We successfully developed an arbitrary micro-patterning method with femtosecond pulses using a multi-level phase type diffractive optical element (DOE) and a focusing objective lens. This DOE consists of two layers: one is the encoding layer, in which Enhancing the diffraction efficiency of continuous-relief diffractive optical elements fabricated by direct laser writing is discussed. A new method of zone-boundary optimization is proposed to correct exposure data only in narrow areas along the boundaries of diffractive zones. The benefit of this method is that the maximum PIDE over the entire waveband for MLDOEs can be obtained. A simple and reliable model is presented as part of the characterization procedure. 84 at 633 nm), and are optically smooth. Diffractive optical elements for shaping and transforming beams have been demonstrated by Karlsson et al. Commercially available single crystal diamond plates (3mm×3mm×0. ck qn il ml rw gt wp lf av nc