Design and alignment of an all-spherical unobscured four-mirror image relay for an ultra-broadband sub-petawatt laser.

We describe the design and alignment of an unobscured reflective image relay for use in an ultra-broadband half-petawatt laser system in development at the University of Rochester's Laboratory for Laser Energetics. The design consists of four spherical mirrors in an unobscured configuration. We show the theoretical basis for such a four-mirror design using first-order optical matrix methods and nodal aberration theory. We also describe the process of aligning this design in a test bed and show the results of this alignment method. We were able to achieve a diffraction-limited nominal design. Upon aligning the design in our test bed, we were able to successfully align the design to achieve our target wavefront error of less than 0.3 waves peak to valley and 0.07 waves rms at the central laser-operating wavelength of 910 nm.

Gaussian curvature and stigmatic imaging relations for the design of an unobscured reflective relay.

We derive the relationship between Coddington's equations and the Gaussian curvature for a stigmatic reflective imaging system. This relationship allows parameterizing off-axis conic optical systems using traditional first-order optics by considering the effective curvature at the center of the off-axis sections. Specifically, we demonstrate parameterizing the system requirements of a 2× achromatic image relay for a terawatt laser system. This system required both collimation (far-field) and pupil imaging (near-field) simultaneously. Long working distances and specific spatial constraints limited the available layout options for the imaging components. By parameterizing these system requirements and packaging constraints, the final specifications could be quickly iterated, while allowing for flexibility in the layout of the system during a multi-year conceptual period.

[Equine dentistry: Survey on Swiss horse owners]. / Zahnbehandlungen beim Pferd: Umfrage bei Pferdebesitzern in der Schweiz.

INTRODUCTION: The interest in equine dentistry has significantly increased in the last 15 years. On the part of the veterinarians as well as of the horse owners there is a strong attention to the topic. The aim of the questionnaire was to investigate amongst horse owners what their level of information and preferences about dental treatment are and how they are implemented. The questionnaire was translated into the three national languages and included 20 questions about level and sources of information, frequency of treatments and the horse owner's stance over sedation of the animals. With a return rate of 45% (1'466 of 3'250 sent questionnaires) significant conclusions could be drawn. Horse owners showed a strong demand for clarification regarding tooth problems, the causes, consequences and methods of treatment. More than half of the owners considered themselves not well informed. The treating person was in 66.7% a veterinarian with a special education. Horse owners indicated that information circulated most frequently by word of mouth recommendations and they explicitly wished information from professional and reliable sources. The questionnaire provided a clear result about current equine dental treatments. We suggest that they should be performed by veterinarians only with a special education.

INTRODUCTION: Au cours des 15 dernières années, l'intérêt pour la médecine dentaire chez les chevaux a de nouveau beaucoup augmenté. Tant les vétérinaires que les propriétaires de chevaux accordent une grande importance à ce sujet. Le but de la présente enquête était de juger le niveau d'information et des préférences en matière de soins dentaires parmi les propriétaires en Suisse et comment elles se concrétisent. Le questionnaire a été rédigé dans les trois langues nationales et comportait 20 questions relatives au niveau et aux sources d'information des propriétaires ainsi qu'à la fréquence des soins dentaires et à la position des propriétaires face à la sédation de leur animal. Avec un taux de retour de 45% (1'466 sur 3'250 questionnaires envoyés), il a été possible de tirer des conclusions significatives. Les propriétaires de chevaux montrent un net besoin en matière d'explication concernant les problèmes dentaires, leurs causes, leurs conséquences et leurs méthodes de traitement. Plus de la moitié se considèrent comme insuffisamment informés. Chez 66.7%, le traitement est effectué par un vétérinaire spécialisé en soins dentaires. Les propriétaires déclarent que les informations leur sont le plus souvent fournies oralement et souhaitent clairement des informations de sources professionnelles et fiables. L'enquête a fourni des données claires sur les soins dentaires actuels chez le cheval. Il en résulte que nous recommandons que ces soins soient effectués principalement par des vétérinaires spécialisés sur ce domaine.