Optical Design and Active Optics Methods in Astronomy

Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are presented. The high accuracy and remarkable smoothness of surfaces generated by active optics methods also allow elaborating new optical design types with high aspheric and/or non-axisymmetric surfaces. Depending on the goal and performance requested for a deformable optical surface analytical investigations are carried out with one of the various facets of elasticity theory: small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, weakly conical shell theory. The resulting thickness distribution and associated bending force boundaries can be refined further with finite element analysis. Keywords: active optics, optical design, elasticity theory, astronomical optics, diffractive optics, X-ray optic

Meeting Report: Aging Research and Drug Discovery

Aging is the single largest risk factor for most chronic diseases, and thus possesses large socioeconomic interest to continuously aging societies. Consequently, the field of aging research is expanding alongside a growing focus from the industry and investors in aging research. This year's 8th Annual Aging Research and Drug Discovery ARDD) meeting was organized as a hybrid meeting from August 30th to September 3rd 2021 with more than 130 attendees participating on-site at the Ceremonial Hall at University of Copenhagen, Denmark, and 1800 engaging online. The conference comprised of presentations from 75 speakers focusing on new research in topics including mechanisms of aging and how these can be modulated as well as the use of AI and new standards of practices within aging research. This year, a longevity workshop was included to build stronger connections with the clinical community

Collider aspects of flavour physics at high Q

This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era of the LHC'', Geneva, Switzerland, November 2005 -- March 200

Active Optics in Astonomy - Modeling of freeform deformable substrates - FIREBall and MESSIER

International audienceActive optics techniques on large telescopes and astronomical instrumentations provide high imaging quality. For ground-based astronomy, the co-addition of adaptive optics again increases angular resolution up to provide diffraction-limited imaging at least in the infrared. Active and adaptive optics marked milestone progress in the detection of exoplanets, super-massive black holes, and large scale structure of galaxies. This paper is dedicated to highly deformable active optics that can generate non-axisymmetric aspheric surfaces-or freeform surfaces-by use of a minimum number of actuators: a single uniform load acts over the surface of a vase-form substrate whilst under reaction to its elliptical perimeter ring. Two such instruments are presented, 1) the FIREBall telescope and MOS where the freeform reflective diffraction grating is generated by replication of a deformable master grating, and 2) the MESSIER wide-field low-central-obstruction TMA telescope proposal where the freeform mirror is generated by stress figuring and elastic relaxation. Freeform surfaces were obtained by plane super-polishing. Preliminary analysis required use of the optics theory of 3rd-order aberrations and elasticity theory of thin elliptical plates. Final cross-optimizations were carried out with Zemax raytracing code and Nastran FEA elasticity code in order to determine geometry of the deformable substrates

Active Optics—Progress in Modeling of Tulip-like Variable Curvature Mirrors

We present new results obtained from the modeling of a tulip-like variable curvature mirror (VCM) in the case of a central force that reacts to its contour. From Nastran finite element analysis, we shows that 3-D optimizations, using non-linear static flexural option, with an appropriate solution sequence, provide an accurate tulip-like VCM thickness distribution. This allows us to take into account boundary conditions, including the thin outer collarette and its link to a rigid ring. Modeling with a quenched stainless steel chromium substrate provides diffraction-limited optical surfaces. Rayleigh’s quarter-wave criterion is performed over a zoom range from flat up to f/3.5 convexity over a 13 mm clear aperture and 10 daN central force. The optical testing results of a prototype tulip-like VCM elaborated from the previous analytic theory, show quasi-diffraction-limited figures for a zoom range up to f/5. The present modeling results should significantly help in the future construction of such VCMs with a zoom range extended up to f/3.5

Active Optics–Freeform Segment Mirror Replications from a Deformable Matrix

We present a new active optics method for making smooth aspheric, or freeform, mirrors by replication technique from an elastically deformable matrix. The mirror replicas provide an equivalent aberration correction to that of an off-axis segment of a Schmidt plate. The method describes geometry of a chromium stainless steel deformable matrix. Polished flat at rest, the matrix was used as submaster when in a bent state for single replications on a glass substrate. Two plane-aspheric segment mirror replicas are then used as a pair of correctors for a spectrograph telemeter. Located outside the Schmidt plate, in opposite diametric directions, the mirror replicas allow aberration compensation of the singlet convex-plane lens used both as collimator and camera-optics of a spectrograph where the beams are passed twice. The spectrograph design is a “white pupil mounting” for a Cassegrainian telescope. The detector focusing is controlled by fusion imaging from the two mirror replicas. Our results show that the He-Ne beams wave-front error performed by the spectrograph, with each of the two replica mirrors passed twice, compensates at least 93% of the required total aspheric sag. This provides satisfactory results for the telemeter focusing device, which then is quasi-diffraction-limited. A similar replication technique is proposed to obtain a pair of off-axis Schmidt plates for a unit magnification Schmidt-Offner “ideal imager”. Such a system is well suited for Laser Guide Star adaptive optics applications in modern astronomy

Active Optics–Freeform Segment Mirror Replications from a Deformable Matrix

We present a new active optics method for making smooth aspheric, or freeform, mirrors by replication technique from an elastically deformable matrix. The mirror replicas provide an equivalent aberration correction to that of an off-axis segment of a Schmidt plate. The method describes geometry of a chromium stainless steel deformable matrix. Polished flat at rest, the matrix was used as submaster when in a bent state for single replications on a glass substrate. Two plane-aspheric segment mirror replicas are then used as a pair of correctors for a spectrograph telemeter. Located outside the Schmidt plate, in opposite diametric directions, the mirror replicas allow aberration compensation of the singlet convex-plane lens used both as collimator and camera-optics of a spectrograph where the beams are passed twice. The spectrograph design is a “white pupil mounting” for a Cassegrainian telescope. The detector focusing is controlled by fusion imaging from the two mirror replicas. Our results show that the He-Ne beams wave-front error performed by the spectrograph, with each of the two replica mirrors passed twice, compensates at least 93% of the required total aspheric sag. This provides satisfactory results for the telemeter focusing device, which then is quasi-diffraction-limited. A similar replication technique is proposed to obtain a pair of off-axis Schmidt plates for a unit magnification Schmidt-Offner “ideal imager”. Such a system is well suited for Laser Guide Star adaptive optics applications in modern astronomy