SPANISH OPTICAL DESIGN MEETING
Friday 22 March 2019
University La Laguna
Santa Cruz de Tenerife - España
Abstracts
Freeform Optics for Virtual Reality
Juan C. Miñano 1,2, Pablo Benítez 1,2, Juan C. González 1, Pablo Zamora 2, Dejan Grabovičkić 2, Marina Buljan 2, Jesús López 2, Milena Nikolic 2, Eduardo Sánchez 2
1 - Universidad Politécnica de Madrid, Cedint
2 - Limbak, Spain and USAVirtual Reality requires novel displays and novel optical designs with extensive use of freeform surfaces to overcome multiple technological challenges: size, weight, increasing its resolution up to the human visual acuity, matching vergence and accommodation. At present commercial VR headsets are rather bulky and heavy, which may be not comfortable enough to use for long periods of time. The main reason for their high volume is the distance required between their lenses and the displays. Here we present novel advanced optical designs, named ThinEyes®, with a dramatically smaller display to eye distance, excelllent image quality and a large field of view.
Industrial Metrology Using Wavefront Technology
Sergio Bonaque Gonzalez
Wooptix S.L., TenerifeWavefront metrology is a key step in the manufacturing of high performance optical components and systems. We present a new wavefront sensor based in a deterministic approach for the propagation of light fields, able to recover the wavefront with the same resolution of the camera used from two intensity images recorded at two different planes substantially inside and outside of focus and in real time. Unlike curvature sensors, we calculate the photon displacement between both planes using geometrical optics approximations and the probability density function of photons. From the calculated displacements the slope of the incident wavefront is then obtained. We will explain the physical basis of this sensor, the optical design and show some applications.
Tolerance Budget and Manufacturing Issues in a
55X Immersion Microscope Objective
Marta de la Fuente and Andres CifuentesASE OPTICS Europe, Barcelona, Spain
Obtaining an excellent nominal optical design microscope objectives is challenging in itself; but the real difficulty comes in the tolerance budget definition. A 55x immersion objective for VIS – NIR is presented with nominal OPD less than lambda/10 over the FOV. The impact of the tolerance set in the as-built system quality is discussed. Different approaches to the tolerance simulation are evaluated including the combined effect of probability density functions for each tolerance type.
Optical Materials for Astronomy Applications
Juan Sanchez 1 and Ralf Jedamzik 2
1 - SCHOTT, Switzerland
2 - SCHOTT, Germany
For approximately 50 years SCHOTT has provided low thermal expansion glass ceramic ZERODUR® for astronomical mirror applications. Recently SCHOTT started the production of ZERODUR® for mirror blanks of the ESO ELT telescope and is expanding the processing capabilities. However, ZERODUR® is not the only material provided for astronomy applications. For many years SCHOTT has also successfully provided design and production of interference filters for space and ground based telescope applications. Other materials often used in astronomy applications are radiation resistant optical glasses and thin glass sheets for solar cell applications aboard space craft.
This presentation will give an overview on the current status of materials for astronomy applications.
SAFARI: a Far Infrared Spectrometer for SPICA Mission
David Arrazola 1, Marianela Fernández 2, Luis M. González 2, Tomás Belenguer 2
1 - ISDEFE, external technical assistant - 28040 - Madrid
2 - Instituto Nacional de Técnica Aeroespacial (INTA)
28850 Torrejón de Ardoz-Madrid
The SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is the next generation of space telescopes addressing the infrared Universe. SPICA will combine a large aperture (2.5m) with a deeply cooled telescope (4.5K) that will provide an optimum environment where instruments are limited only by the cosmic background itself. The main science objective is to analyze the galaxy evolution over cosmic time. A secondary scientific objective is to study line profiles at higher spectral resolution to discern the in-fall and outflow of matter from active galactic nuclei and star-forming galaxies.
SAFARI instrument on SPICA is a high sensitivity grating-based spectrometer operating in the 34-230µm wavelength range. The scientific drivers lead to the implementation of two modes of operation. A first mode known as Low-Resolution (LR), or nominal mode (R~300). A second mode of operation, High-Resolution (HR), that implies to include a Martin-Puplett interferometer to achieve the required spectral resolution (R~2000-11000). There shall be three spatial pixels operating in parallel. SAFARI shall provide point source spectroscopy with diffraction-limited capability in four spectral bands and a field of view (FoV) on sky over 2’x2’.
The instrument includes a pick-off mirror (PoM) that is an optical interface with the SPICA telescope defined as an incoming beam of F/5.4 and 2.5 meters of entrance aperture. The optical system is all-reflective (with the exception of the wire grids and filters) and consists of three main modules; all of them are finite conjugate optical systems. The input optics module (IOM) is an unobscured reflective Offner relay system of magnification 1X. It has two principal functions: to generate an image of the telescope entrance pupil on the Offner relay secondary mirror and to reimage the telescope focal plane onto the output port of the IOM. The output port will be a slit-type FoV with two slits, one per mode of operation.
The next module, which includes the MP-FTS interferometer, is the Band & Mode Distributing Optics (BMDO). It splits the radiation band into the four different spectral bands by means of a set of dichroics, filters and collimating and focusing optics. The field image existing in the output of the BMDO constitutes the entrance to the Grating Module Optics (GM). Each Grating module receiving a beam F/5.4 at the focal plane of the BMDO, and as a slit-type extension FoV. Grating Modules provide spectral dispersion by means of linear and reflective diffraction gratings and the final image onto the detectors for each of the four spectral bands, with different numerical aperture for each one. These subsystems have a pupil image close to each grating location. The image sampling and the size of the detector elements are key drivers in this optical module design.
Optics in Cell Phones
Matt Novak
Optical Solutions Group, Synopsys Inc
Mobile devices are now part of the everyday lives of billions of people all over the world, delivering functional, secure and light weight communication capability. While optics for these devices has played an increasingly important role, the packaging requirements present unique challenges. In this work, we describe the design of a compact multi-element aspheric lens for mobile devices. Starting from an initial patent starting point design, we improve the lens using powerful optical design software optimization capabilities, including unique material substitution and tolerance desensitization algorithms. We describe the starting point, the design method and show the final results.
Extreme wide-angle lens design for land, underwater and both
Vladan Blahnik
Carl Zeiss AG, Oberkochen
Following the inspiration of ocean scientists and filmmakers like Jacques Cousteau professional equipment and dedicated underwater lenses were developed beginning in the 1960s. For many decades underwater imaging equipment mainly targeted for professional applications like documentary film, cinematography, industrial and military applications and was usually bulky and expensive. The digital era with small, high-performance image sensors opened a broad consumer market with water-proof point & shoot cameras and action cams. Recently also underwater drones with cameras for remote control entered the consumer market.
For underwater operation standard land lenses are usually combined with flat or dome ports. We show that for extreme wide angle lenses both setups suffer from severe aberrations. Underwater front converters can significantly improve image quality, however all these solutions are outperformed by optical designs optimized for water. Ideally water-proof cameras should capture excellent pictures in both environments land and underwater. The lens design of such an all-round compact wide-angle lens is challenging, requiring a simultaneous optimization with moveable lens groups for land and underwater configuration respectively.
An overview over different underwater applications like compact consumer cameras, cinematography or deep sea exploration is given, also discussing potential and limits of digital image corrections.
Design and Fabrication of Microstructured Polymer Optical Fibers
Joseba Zubia, E. Arrospide, G. Durana and M. A. Illarramendi
Universidad del País Vasco-Euskal Herriko Unibertsitatea
In this paper we will show a methodology for the design and fabrication of a wide range of microstructured polymer optical fibres (mPOFs). The fabrication of mPOFs can be summarized in four steps. The first step is the geometric design of the mPOF with the suitable propagation characteristics. This design includes the number, shape, location, symmetry and size of the holes at the cross section of the fiber. The second step is the drilling of the preform made according to the previous design. Third step is the stretching of the primary preform down to a thinner secondary preform or to a cane. Fourth step is the drawing of the primary or secondary preform. Afterwards the mPOF can be sleeved to modify their propagation characteristics. All steps of the process will be discussed in detail from the theoretical design to the fabrication and characterization.
The Adaptive Optics facility for the future EST
Luz Maria Montoya Martinez
Instituto de Astrofisica de Canarias
The European Solar Telescope (EST) will be the largest solar telescope ever built in Europe
. It will have unique adaptive optics capabilities which allows measurement of the properties of the solar magnetic field with great accuracy and high spatial resolution. The Multi-Conjugate Adaptive Optics (MCAO) system features one ground DM and 4 high altitude DM’s, and combines a narrow field high order wavefront sensor, providing the information to correct the ground layer, and a wide field lower order sensor to control the higher altitude mirrors. End to end simulations have enabled defined and optimized WFS and DMs parameters such as WFS asterism, number and height of DMs, field of the subaperture WFS. On the other hand simulations have afore some issues intrinsic to the Solar AO. Although some MCAO system features have been tested on sky, in order to validate the results obtained with simulations, a test bench is being designed in the headquarters of the IAC. This demonstrator will provide the experience to face the challenge of the future EST MCAO.
Poster Abstracts
Shoulder-surfing prevention on multilayered light-field displays
David Carmona-Ballester1, Juan M. Trujillo Sevilla2, Sabato Ceruso2, Oscar Casanova-González2
(1) Universidad de La Laguna
(2) Wooptix S.L.
In this work we present a novel application in the field of shoulder-surfing prevention by using a light-field display consisting of a multilayered structure of LC screens. By controlling the directionally displayed content, we can discriminate between authorized and unauthorized observers. Optimizations regarding different parameters were assessed, i.e, number of unauthorized/authorized observers, quality and complexity of the contents, and physical limitations. Tests were made in simulations and a real model implementation.
Fluorescence Intensity Ratio and Whispering Gallery Mode techniques
in optical temperature sensors - Comparative study
F. Paz-Buclatin1, S. Ríos1, IR. Martín,1,2
(1) Departamento de Física, Universidad de La Laguna
(2) Instituto Universitario de Materiales y Nanotecnología (IMN), Universidad de La Laguna
The thermal sensing capabilities of different morphologies (microsphere, fiber, and bulk glass) of an Er3+ doped oxyfluoride glass were characterized in order to determine the most suitable material to be developed as a temperature sensor. For the microsphere and fiber, the displacements of the Whispering Gallery Mode (WGM) peaks were calibrated with pump power and temperature using a confocal microluminiscence setup. WGM are resonances of a wave field inside a cavity due to the successive total internal reflections on its curved surfaces. The resonance condition depends on the dimension and refraction index of the cavity, which in turn are dependent on the temperature through the thermal expansion coefficient and thermo-optic coefficient, respectively. On the other hand, Fluorescence Intensity Ratio (FIR) technique was used to calibrate the temperature of the bulk glass placed inside a tubular oven. This technique consists of analyzing the fluorescence intensity of thermally coupled energy levels wherein a thermal redistribution of population occurs as the temperature of the material varies. In order to compare the sensor performance of each sample, the relative sensitivity and temperature uncertainty were determined. A relative sensitivity of 9.9 x 10-5 K-1 was obtained for the microsphere and the fiber and 1.0 x 10-2 K-1 for the bulk glass, a value two orders of magnitude greater than that of the microresonators. On the other hand, the microsphere and fiber presented temperature uncertainties for the 670 nm emission band an order of magnitude lower than that of the bulk glass: 0.11 K, 0.37 K, and 1.8 K respectively. The results of this study facilitate the selection of the morphology of an optically active material and the corresponding sensing method to be employed in the development of an optical temperature sensor.
Optical Design of the Illumination and Imaging Trains of Suffice Microscope
A. Marzoa1, R. Bola1,2, D. Treptow1, E. Martín-Badosa1,2 and M. Montes-Usategui1,2
(1) Departament de Fisica Aplicada, Universitat de Barcelona
(2) Institut de Nanociència i Nanotecnologia, BarcelonaWe present the design of the illumination and imaging trains of the SUFFICE (Super-Fast and Flexible Digital Confocal Microscope) microscope: a new type of confocal microscope specially designed for a new microscopy technique based on acousto-optic deflectors (AOD) under protected technology.
This new method is based on the injection of complex acoustic signals computed with acousto-holographic algorithms to the AOD using and arbitrary wave generator (AWG). This procedure, in combination with virtual pinholing, permits the generation of structured illumination patterns for fluorescence microscopy applications with confocal filtering, resulting in a very flexible instrument.
The optical design procedure is described, taking into account the requirements, restrictions and specifications needed for the application. A ZEMAX® simulation is carried out, leading to a diffraction-limited system compatible with commercial inverted microscopes, facilitating the building of the set-up in the laboratory. Finally, results obtained with the new apparatus are shown, pointing out the main advantages of the system.
Refractive index characterization in biological tissue through optical sensing
Kevin Soler-Carracedo1, Fernando Lahoz1, Inocencio R. Martín1,Virginia Mesa-Infante1, Tomás González-Hernández1, Germán Cuesto1, Ángel Acebes1, Jorge Gil-Rostra2, Francisco Yubero2, Agustín R. Gonzalez-Elipe2
(1) Universidad de La Laguna, Santa Cruz de Tenerife, Spain
(2) Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla), Sevilla, SpainIn this paper, we present a new technique that allows mapping the refractive index of an organic tissue as a method to characterize its density. Here, mice brain slices stained against Tyrosine Hidroxylase (TH) enzyme and revealed with a Cy2 immunofluorescent secondary antibody were introduced in a Fabry-Perot (FP) microcavity, acting as a photonic structure. This cavity is formed by two parallel fused silica plates covered with dichroic Bragg Reflectors (BR) with a separation of 60 microns. The BRs were obtained by a multilayer deposition of Nb2O5/SiO2 thin films. They were designed to reach high reflection in the green region, while showing great transparency in the blue or in the infrared (IR) spectral, facilitating the use of organic dyes that tent to show green emission.
Using Nanotechnology to Obtain Optical Nanocomposites with Pre-Designed Properties
Pablo A. Postigo
Group of Nanophotonic Devices
Instituto de Micro y Nanotecnología (Centro Nacional de Microelectrónica)
Madrid, Spain
The combination of nanotechnology with optics can produce new materials with new predefined optical properties. The use of materials in nanometric sizes favors the integration of them in a new nanocomposite, and the different optical properties allows the obtention of an optical nanocomposite with mixed or even new optical properties. The combination of nanomaterials can be in an ordered manner, as a photonic crystal, or in more random way. It is possible to calculate the optical properties of the nanocomposite using different methods, depending on the complexity of the nanocomposite. The fabrication of the nanocomposite can be performed also with different techniques depending on the type (nanowires, nanopillars, nanolayers) and size (mm, cm, m) of the optical nanocomposite needed . As an example, we show the fabrication of new optical nanocomposites for confocal fluorescent microscopy with new optical properties to enhance the intensity and to remove the background light. The techniques shown can be used also for the fabrication of optical nanocomposites for optical sensors in satellites or specific parts of telescopes.
The 4 meter New Robotic Telescope
M. Torres and A. Oria
On behalf of the NRT collaboration
We present an overview of a project to build a 4 meter diameter telescope (New Robotic Telescope: NRT) with fully robotic operation. The telescope will be sited on the Observatory of Roque de los Muchachos (ORM) in the island of La Palma (Spain). The project is currently in a conceptual phase design and when it enters into operation in five years time, NRT will be the largest robotic telescope in the world. This, in conjuction with an extremely fast response (< 30 s) and a versatile and flexible instrumentation in the optical and near infrared ranges will make NRT a world leading facility in the area of time domain astrophysics. In this contribution, we present the status of the project and focus on some of the technical challenges in optics, mechanics and electronics associated with the special operation of the telescope.