Today’s optical fabrication and testing technologies are facing ever-increasing demands from industry and science. This is driven by tough requirements for cost and time reduction in production and R&D as well as by rapidly developing new application fields.

The optical elements become larger, thinner, segmented … or smaller. The optical profile is going up to freeform and discontinuous. The figure and finish error specifications are becoming tighter all through the Power Spectral Density curve. Our substrate material choice is enlarging with new ceramics, metal alloys or organic material. The wavelengths of interest are pushing towards EUV and x-rays on one hand or TeraHerz waves on the other hand, etc.

Speed and accuracy of metrology are more than ever as important as the manufacturing process itself and remain key contributor to the economic success of industrial production and new optical manufacturing methods. New techniques like deflectometry offer new perspectives and conventional instrument still see progress in quality, accuracy or on-the-field efficiency thanks to intelligent and user-friendly driving software.

The aim of this conference is to review with the community the latest developments achieved in optical fabrication, testing, and metrology. ;
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Conference 11873

Optical Fabrication, Testing, and Metrology VII

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  • Plenary Session I: Monday
  • Plenary Session II: Tuesday
  • From Design to Manufacturing and Alignment
  • Diffractive Structures
  • Metrology I
  • Metrology II
  • Poster Session
Information
In addition to the pre-recorded on-demand presentations available for the presentations listing below, this conference will also hold a live-stream broadcast of its presentations.

Pose your questions and join us for this unique opportunity for some interesting networking and discussion; plan to attend the conference live broadcast.
If you are unable to take advantage of the live session, pre-recorded on-demand presentations will remain available through the digital forum duration.

Monday, 13 September: 12:40 to 15:20 hrs CEST
Times for this live event are all Central European Summer Time, CEST (UTC+2:00 hours)

Detailed schedule is listed in each conference session below.
Link to join this live broadcast will be available to registered participants on this website on Monday, 13 September at 13:15 hrs CEST.
Plenary Session I: Monday
Livestream: 13 September 2021 • 09:00 - 11:00 CEST
11871-500
Author(s): Vladan Blahnik, Carl Zeiss AG (Germany)
On demand | Presented Live 13 September 2021
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The iconic photos of NASA's first space missions and Moon landings from the 1960s onwards were captured with ZEISS camera lenses mounted on Hasselblad cameras. They adorned the covers of many newspapers and magazines and appeared in color for the first time ever, as special issues. Meanwhile, NASA's scientists were evaluating the scientific images: the photogrammetric images taken while in orbit were combined to form a detailed lunar map, the panorama pans on the lunar surface were turned into a topographic map of the landing area, and the pictures with broadband achromatized UV lenses gave insights into the overall soil conditions on the Moon and the Earth. The talk will provide an overview of all the camera lenses developed by ZEISS for NASA. It will look at their technical specifications, describe the development work done for these lenses, and delve into the history of the partnership between NASA, Hasselblad, and ZEISS. Just like space travel, the launch of mainframe computers at that time also spurred on optical design. Other ZEISS products for photography, cinematography, aerial photogrammetry, and optical lithography also benefited from these developments.
11871-501
Freeform optics design (Plenary Presentation)
Author(s): Pablo Benitez, Univ. Politécnica de Madrid (Spain)
On demand | Presented Live 13 September 2021
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The higher flexibility of freeforms has opened the possibility to find better solutions than classical surfaces many optical problems, especially those whose specifications (either optical or geometrical) are far from rotational symmetry. For instance, short through distance multimedia projectors cannot be placed in front of the center of the projected image without blocking the spectators’ view, and this requires the projection to be done from one side. Offset rotational symmetric solutions are suboptimal, and a freeform projector can improve the image quality on the target area with the same number of surfaces or can match the quality with fewer optical surfaces 1. Similarly, many head-worn displays are located close to the eyes of the user to make the headset sleeker. In this case, some parts of the physical display are used at very high emitting angles and rotational symmetric cannot provide optimal solutions for this configuration. In nonimaging applications, low-beam headlamps of cars also need to produce an asymmetric pattern on the road to avoid blinding the incoming drivers. Freeforms permit to solve this design problem efficiently, and match aesthetic constraints. The continuous progress in the technology to produce and test freeforms, as occurred in the past with rotational aspherics, is pushing optical designers to consider more and more the use of freeforms in their designs. However, the also higher complexity of these surfaces introduces multiple challenges in their design since traditional design methods have been focused in rotational optics. These challenges go from finding the best mathematical description of the optical surfaces to the design algorithms themselves. We’ll review the main design techniques proposed to design freeforms and illustrating its use in specific examples for several applications.
Plenary Session II: Tuesday
Livestream: 14 September 2021 • 16:00 - 18:00 CEST
11871-600
Lens design through the ages (Plenary Presentation)
Author(s): John R. Rogers, Synopsys, Inc. (United States)
On demand | Presented Live 14 September 2021
11876-601
Author(s): Bernard C. Kress, Microsoft Corp. (United States)
On demand | Presented Live 14 September 2021
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For the past decade, optics and display hardware developments for mixed reality and smart glasses were merely a shot in the dark, providing enough display immersion and visual comfort for developers to build up apps, especially for the enterprise field. Today, as universal use cases for consumer emerge such as co-presence, digital twin and remote conferencing, new optical functionalities are required to enable such experiences. It is not only a race to smaller form factor and light weight devices for large field of view (FOV) and lower power, but the requirements are also on additional display and sensing features specifically tuned to implement such new universal use cases. Broad acceptance of wearable displays especially in the consumer field is contingent on enabling these new display and sensing requirements in small form factors and low power. This talk will focus on waveguide combiner technologies and how these architectures have evolved over the past years to address such new requirements
From Design to Manufacturing and Alignment
Livestream: 13 September 2021 • 12:40 - 13:15 CEST
In addition to the pre-recorded on-demand presentations available for the presentations listing below, this conference session will hold a live-stream broadcast of its presentations.
Times listed are Central European Summer Time, CEST (UTC+2:00 hours)

12:40 hrs: Welcome and Introduction by the conference chairs

12:45 hrs 11873-1: Optical fabrication chain modeling (Invited Paper)

12:55 hrs 11873-2: Fabrication of free-form micro-optics: design assessment for manufacturability

13:05 hrs 11873-4: Overview of ELT mirrors manufacturing and metrology at Safran REOSC

For Sessions 2-4 timing please see the respective session listings..
11873-2
Author(s): Tamara Aderneuer, Oscar Fernández, Ctr. Suisse d'Electronique et de Microtechnique SA (Switzerland); Julio Chaves, Ruben Mohedano, Limbak (Spain); Rolando Ferrini, Ctr. Suisse d'Electronique et de Microtechnique SA (Switzerland)
On demand
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Free-form optics gain increased interest since they can overcome limitations of rotationally symmetric optical components. This results in better performance and compactness of optical designs. New technologies paved the way to fabricate such free-form micro-optical components and thus realize designs, which were not possible with conventional technologies. Nevertheless, there are still many research and development activities to push current limitations further. Especially for free-form optics designs containing many individual elements in combination with complexity of shape, many challenges remain to be solved. When free-form micro-optical designs contain thousands of individual microscale elements, it is far from trivial for designers to judge the manufacturability. Currently it requires several iteration cycles until a design is fabricated, for example, because manufacturers optimize their processes to minimize shape deviations from the nominal design and as designers adapt the designs to meet the manufacturing limitations. To decrease such time consuming and costly steps, we present design for manufacturing tools to decrease information gaps between designers and manufacturers, such that constraints can be considered at an early stage. The computer aided design (CAD) tools can analyze models containing several hundreds of single elements. We implement fabrication constraints from multiple state of the art micro-optical fabrication technologies such as laser micro-machining, two photon polymerization and ultra-precision micro-machining. This facilitates the choice of technology as well as identification of critical parts at the beginning of the design process. We put a focus on developing user-oriented tools, with little software expertise needed and clear visualization. With this approach we target to overcome present communication difficulties between experts from different fields. Furthermore, our tools are flexible for adaptions, such that new fabrication advances can be continuously updated.
Diffractive Structures
Livestream: 13 September 2021 • 13:15 - 13:40 CEST

In addition to the pre-recorded on-demand presentations available for the presentations listing below, this conference session will also hold a live-stream broadcast of its presentations.
Times listed are Central European Summer Time, CEST (UTC+2:00 hours)

13:15 hrs 11873-7: Usage of dry processes for the formation of diffractive structures on Ti and Ti/Si films

Break: 13:25 to 13:40 hrs

For Sessions 1, & 3-4 timing please see the respective session listings.
Metrology I
Livestream: 13 September 2021 • 13:40 - 14:40 CEST
In addition to the pre-recorded on-demand presentations available for the presentations listing below, this conference session will also hold a live-stream broadcast of its presentations.
Times listed are Central European Summer Time, CEST (UTC+2:00 hours)

13:40 hrs 11873-8: The modern way of refractive index measurement of optical glass at SCHOTT

13:50 hrs 11873-9: The interferometric test bench for the ELT M2 polishing and validation

14:00 hrs 11873-10: How to provide reliable metrology of online laser-induced damage on large fused silica optics using digital image correlation

14:10 hrs 11873-11: Flexible and fast measurement of large off-axis optics using a non-contact coordinate measuring machine

14:20 hrs 11873-12: Measurement of a highly freeform surface using a cylindrical null-screen
Break: 14:30 to14:40 hrs

For Sessions 1-2 & 4 timing please see the respective session listings.
11873-10
Author(s): Guillaume Hallo, Chloé Lacombe, Romain Parreault, Nadja Roquin, Thierry Donval, Laurent Lamaignère, Jérôme Néauport, CEA-Cesta (France); François Hild, Ecole normale supérieure Paris-Saclay (France)
On demand
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Final fused silica optics of high energy fusion class laser facilities are one of the components that limit the UV laser energy available for experiments. These final optics suffer from laser-induced damage. Some solutions are available to limit laser damage growth and to increase optics lifetime. However, to use them, it is necessary to be able to detect damage initiation as soon as possible, and to follow damage growth efficiently. An imaging system and a lighting source make the observation of laser damage sites possible after each laser shot without removing the optical components. Laser damage detection algorithms exist but they are not sufficiently efficient to provide reliable monitoring of damage growth over time because of small repositioning fluctuations of the optical system. An effective solution based on digital image correlation and brightness/contrast corrections is proposed to detect and follow laser damage sites as soon as they initiate in an automatic way. The effectiveness of the presented method is compared to the widely used method that is based on the analysis of local signal-to-noise ratio.
11873-11
Author(s): Rens Henselmans, Dutch United Instruments (Netherlands)
On demand
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Optical systems often employ off-axis optics to prevent obscuration or because of geometric constraints. Measuring these optics in conventional interferometric setups is challenging: for cases other than off-axis parabolas, a CGH has to be used and setup size grows with the off-axis distance. Measuring large convex surfaces is particularly difficult. Production methods for off-axis surfaces often introduce mid-spatial frequency errors, which are a function of their influence function (spot size) and the machining motion profile. The NMF600 S non-contact measurement machine by Dutch United Instruments (DUI) allows flexible and high-point density measurement of off-axis surfaces by measuring them as an on-axis freeform. It has a cylindrical coordinate measuring machine setup with an optical probe. A high-stability separate metrology system relates the probe position to the product position. This gives the versatility to measure all sorts of dimensions and surface shapes (flat, convex, concave, asphere to freeform with up to +/-2.5 mm departure from the best-fit asphere), the accuracy to capture the nanometer level height variations and the speed to gather the required high data density to characterize the mid-spatial content. The machine has a table diameter of 600 mm allowing for off-axis measurement of parts that fall within this diameter, and centred measurement as a freeform of all parts outside this diameter. The machine software performs all coordinate transformations automatically, such that the user only has to give the optical formula and the off-axis shift and tilt. This way surfaces can be setup in minutes. Example measurements of off-axis parabolas, a 550 mm rectangular asphere and an ellipsoid with 2.5 mm non-rotational symmetry will be shown. All measurement show nanometer level repeatability, high-point density and measurement times in the order of tens of minutes.
11873-12
Author(s): Oliver Huerta-Carranza, Manuel Campos-García, Daniel Aguirre-Aguirre, Univ. Nacional Autónoma de México (Mexico); Brenda Villalobos-Mendoza, Univ. de Monterrey (Mexico); Victor Ivan Moreno-Oliva, Univ. del Istmo (Mexico)
On demand
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We propose a method to design the null-screen on a cylindrical surface when the surface under test is a freeform, this implies that the surface is described by a complex analytical expression. Also, the method avoids overlapping objects in the image plane this assures the appropriate correlation between the object and the image points. The surface under study was designed using Zernike polynomials and it was built through a 3D printer and CNC machine. To retrieve the surface sagitta, in previous work, we obtained the best-fitting surface using a probabilistic algorithm. In this work, we propose to measure the slopes of the test surface in the x and y directions, and by integration, we calculated the sagitta of the test surface. We present a comparison between both methods to show which of them recovers the shape of the surface more accurately.
Metrology II
Livestream: 13 September 2021 • 14:40 - 15:20 CEST
In addition to the pre-recorded on-demand presentations available for the presentations listing below, this conference session will also hold a live-stream broadcast of its presentations.
Times listed are Central European Summer Time, CEST (UTC+2:00 hours)

14:40 hrs 11873-13: Optical functionality simulation based in traceable characterization of optical components

14:50 hrs 11873-14: A simple collimator design for measuring focal spots with high dynamical range

15:00 hrs 11873-15: Measurements of corneal topography using a compact null-screen corneal topographer with a mobile device

15:10 hrs 11873-16: Development of method for measuring a light energy distribution over foci for mould of diffractive component of bifocal intraocular lens

Please Note: for Sessions 1-3 timing please see the respective session listings.
11873-14
Author(s): Bruno J. Le Garrec, LASYEX s.r.o. (Czech Republic), Ecole Polytechnique (France); Mélanie Chabanis, Ecole Polytechnique (France); Flemming Tinker, Michael Uwakwe, Aperture Optical Sciences Inc. (United States)
On demand
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High intensity lasers in the 10-PW range require large optics (up to 600 mm diameter) with very high surface quality. In our case we have been facing troubles coming from very small wavefront defects at high spatial frequencies; defects that were not visible when checking with a Fizeau-type interferometer that was providing a PSD record. These very small defects were creating high-contrast Talbot fringes when propagating our laser beam. We decided to check carefully how the focal spot of our laser beam would be affected and this is the reason why we decided to build a collimator. Our collimator is a classical Newton-type telescope that can be used either off-axis with a useful diameter of 200 mm or on- axis with a low central occultation (< 12%) and a useful diameter of 410 mm. The on-axis parabola (diameter 412.8 mm-16.25 inches and focal length 2032 mm-80 inches ) was supplied by Edmund Optics. The beam comes from a collimated laser source (either at 532, 633 or 820 nm) and then focused through a 30-m pinhole by a microscope objective (x 20) in order to obtain a "clean" spatial distribution. In the collimated part, optical densities calibrated at the operating wavelength(s) are inserted in order to control the intensity in the focal spot. An operating range of 10 orders of magnitude is obtained with a source emitting 5 mW. The measurement is made in the focal plane of the component to be tested with a CCD camera mounted on x-y-z translation stages. In cooperation with Aperture Optical Sciences Inc., the collimator was tested with known components and results compared with other available systems. Finally we are able to identify and to measure periodic defects as low as /2500 and to connect them with their PSD value.
11873-15
Author(s): Manuel Campos-García, Luis Ángel Pantoja-Arredondo, Daniel Aguirre-Aguirre, Univ. Nacional Autónoma de México (Mexico); Victor Ivan Moreno-Oliva, Univ. del Istmo (Mexico); Oliver Huerta-Carrranza, Univ Nacional Autonoma de Mexico (Mexico); Victor de Emanuel Armongol-Cruz, Univ. Nacional Autónoma de México (Mexico)
On demand
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In this work, we use a null-screen corneal topographer with a semiradial spot pattern by using a mobile device’s camera to obtain images of the reflected pattern with the main aim of obtaining the corneal topography. First, we discuss how to integrate the system to calibrate it by testing a reference surface where we obtain optical parameters such as the radius of curvature and the conic constant, as well as elevation, sagittal curves, and meridional curvature maps with this method. Finally, we show some prelaminar measurements of the topography of some human corneas.
11873-16
Author(s): Victor P. Korolkov, Institute of Automation and Electrometry (Russian Federation); Polina Konoshenko, Novosibirsk State Technical Univ. (Russian Federation); Sergey L. Mikerin, Dmitrij A. Belousov, Anatoly I. Malyshev, Sergey K. Golubtsov, Institute of Automation and Electrometry (Russian Federation)
On demand
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Bifocal diffractive-refractive intraocular lenses (BDRIOL) are used in ophthalmology to replace natural lenses that are clouded by cataracts. In Russia, the REPER company developed a BDRIOL manufacture technology on the base of a liquid photopolymer frontal polymerization placed between two transparent fused silica moulds. One of them has a spherical shape, the other has a flat surface with a diffractive optical element (DOE). In our BDRIOL design the diffractive structure depth changes so that the energy distribution over the foci weakly depends on the pupil diameter. Zeroth and first orders efficiencies should almost the same. Measurement of this distribution is complicated due to the diffractive profile depth corresponds to the operation of a polymer lens in the eye and is significantly greater than required for working in air. We have proposed to use temporal planarization of the diffractive mould to measure energy distribution over foci. The diffractive structure is filled with a material that provides approximately the same module of refractive index difference with fused silica as between the polymer and vitreous body of the eye. This difference is adjusted by the temperature and time selection at the photoresist baking. The sign inversion of the refractive index difference in comparison with the operating conditions in human eye changes the DOE focus to positive. The paper discussed specific photoresist treatment, refractive index measurement and preliminary results of the developed method.
Poster Session
11873-17
Author(s): Angela Soria-Garcia, Univ. Complutense de Madrid (Spain); Javier Fantova, Alejandro San Blas, CEIT-IK4, Basque Research and Technology Alliance, Univ. de Navarra (Spain); Jesus del Hoyo, Luis Miguel Sanchez-Brea, Javier Alda, Univ. Complutense de Madrid (Spain); Ainara Rodríguez, Santiago M. Olaizola, CEIT-IK4, Basque Research and Technology Alliance, Univ. de Navarra (Spain)
On demand
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Diffractive Optical Elements (DOEs) are amplitude and/or phase masks that can be applied to light beams to modify their phase and/or intensity distribution. They are applied in holography, beam shaping, generation of exotic beams (Hermite-Gauss, Gauss-Bessel, vortex beams, etc.), atomic physics, etc. They can be implemented using spatial light modulators or micro-structured materials. Femtosecond laser writing is a very promising technique for fabricating photonic and micro-optics devices in metallic and dielectric materials. Compared to other methods, it has many advantages like a reduction of the amount of energy required to fabricate devices, and the absence of pollutant chemicals, becoming one of the most environmentally friendly fabrication techniques. One technique for implementing amplitude modulation DOEs is using dielectric samples covered with a metal thin film (~100-300 nm). Then, the metallic film is selectively removed by laser ablation. This allows the engraving of a binary amplitude mask, where the remaining metallic coating reflects the electric field while the exposed dielectric area supports its transmission. Hence, these masks may work in both transmission and reflection. Although laser processing of DOEs has been successfully proved, some challenges still remain and should be addressed to optimize their behaviour. One of the problems treated in this contribution is the effect of damage on the dielectric substrate under the metallic coating. This happens since the energy used to remove the metallic layer can also affect the dielectric sample. Another issue related to the ablation process is the different ablation strategies to engrave a given spatial distribution. Here, the laser is driven to process a matrix of points, or it can work in raster mode across the sample. We will analyze these two effects to properly understand the limitations of the technique and to find some useful strategies to overcome them when engraving DOEs through laser ablation.
11873-20
Author(s): Oliver Huerta-Carranza, Manuel Campos-García, Daniel Aguirre-Aguirre, Univ. Nacional Autónoma de México (Mexico); Brenda Villalobos-Mendoza, Univ. de Monterrey (Mexico); Víctor Iván Moreno-Oliva, Univ. del Istmo (Mexico)
On demand
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We use the null-screen method to evaluate in a qualitative and quantitative way the shape of a parabolic trough solar collector. When a parabolic trough solar collector is fabricated can occur that the manufacturing errors are large. In some cases, when using the null screen method, the objects in the image plane are overlapped. This problem is solved adequately by placing the CMOS sensor and LCD null-screen in off-axis positions. Also, we propose to display a suitable null-screen on the LCD screen. In the first evaluation the null screen is composed of few object points, in the next evaluation, we change the distribution of objects that compose the null screen with the aim of increasing the measurement points. Finally, the data corresponding to each evaluation is merged in only one set of evaluation data to calculate the surface sagitta from slope measurements of the test surface in the x and y directions.
11873-21
Author(s): Victor Ivan Moreno-Oliva, Jose Angel Desales-Dominguez, Edwin Román-Hernández, Univ. del Istmo (Mexico); Manuel Campos-García, Univ. Nacional Autónoma de México (Mexico)
On demand
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In this work, we analyze the advantages and limitations of the systems of low speeds of frames per second (fps) for the estimation of the vibrations measurements in systems where optical techniques are used. The acquisition systems with low fps are interesting because they are not expensive. In this way, the aim of this work is to compute the limit speed to obtain good resolutions in data collection. Laser triangulation technique is implemented to determine the natural frequency of vibration of a system using a cantilever beam, as a standard example. The results are compared, with a commercial accelerometer.
Conference Chair
Safran Reosc (France)
Conference Chair
Univ. of Deusto (Spain)
Conference Chair
SUSS MicroOptics SA (Switzerland)
Program Committee
Berliner Glas KGaA Herbert Kubatz GmbH & Co. (Germany)
Program Committee
Xinbin Cheng
Tongji Univ. (China)
Program Committee
Optimax Systems, Inc. (United States)
Program Committee
Doric Lenses Inc. (Canada)
Program Committee
OST Ostschweizer Fachhochschule (Switzerland)
Program Committee
Pierre Gloesener
AMOS Ltd. (Belgium)
Program Committee
Philippe Godefroy
Winlight System S.A. (France)
Program Committee
Glyndwr Innovations Ltd. (United Kingdom)
Program Committee
Photon Engineering LLC (United States)
Program Committee
Savimex (France)
Program Committee
Rafael Advanced Defense Systems Ltd. (Israel)
Program Committee
asphericon GmbH (Germany)
Program Committee
Thales Angénieux S.A. (France)
Program Committee
Commissariat à l'Énergie Atomique (France)
Program Committee
Manfred Prantl
Alicona Imaging GmbH (Austria)
Program Committee
Fraunhofer-Institut für Angewandte Optik und Feinmechanik IOF (Germany)
Program Committee
Arkadiusz Swat
CRW Telesystem-Mesko Sp. z o.o. (Poland)
Program Committee
Jos. Schneider Optische Werke GmbH (Germany)
Program Committee
Alexander Yascovich
Space Research Institute (Russian Federation)