We report on the first experimental demonstration of higher-order Laguerre-Gauss (LG(p)(ℓ)) mode generation and interferometry using a method scalable to the requirements of gravitational wave (GW) ...detection. GW detectors which use higher-order LG(p)(ℓ) modes will be less susceptible to mirror thermal noise, which is expected to limit the sensitivity of all currently planned terrestrial detectors. We used a diffractive optic and a mode-cleaner cavity to convert a fundamental LG(0)(0) Gaussian beam into an LG(3)(3) mode with a purity of 98%. The ratio between the power of the LG(0)(0) mode of our laser and the power of the LG(3)(3) transmitted by the cavity was 36%. By measuring the transmission of our setup using the LG(0)(0), we inferred that the conversion efficiency specific to the LG(3)(3) mode was 49%. We illuminated a Michelson interferometer with the LG(3)(3) beam and achieved a visibility of 97%.
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Advanced Virgo is a major upgrade of the Virgo gravitational-wave detector, aiming to increase its sensitivity by an order of magnitude. Among the main modifications of the instrument, the size of ...the laser beam inside the central area has been roughly doubled. Consequently, the input/output optics systems have been re-designed. Due to the overall Advanced Virgo optical scheme, high-magnification and compact telescopes are needed. These telescopes also have to fulfill stringent requirements in terms of aberrations, separation of secondary beams and scattered light. In this paper we describe the design of the Advanced Virgo telescopes and their estimated performances in terms of tuning capability and optical properties.
The LISA project is a space mission that aim at detecting gravitational waves in space. An electro-optical simulator called LISA On Table (LOT) is being developed at APC in order to test noise ...reduction techniques (such as Timed Delayed Interferometry) and instruments that will be used. This document presents its latest results: TimeDelayed Interferometry of 1st generation works in the case of a simulated white noise with static, unequal arms. Future and ongoing developments of the experiment are also addressed.
This paper describes the progress on a hardware simulator of eLISA developed at the APC laboratory in Paris, France. It is designed to simulate realistic noise and the appropriate delays resulting ...from the huge distances the laser has to travel between the eLISA spacecrafts. We present the experimental setup consisting of an optical and electric interferometer. Also, the time delay interferometry noise reduction method and its performance on simulated signals in the simplest transponder case will be described.
We report on a novel optical system for discrete selection of precise, user-defined spectral regions from the emitted spectrum of a white light source. The device, which is based on an array of ...electrostatically actuated, achromatic micro-mirrors, allows us to select signals with spectral widths between 4 and 15 nm from the super-continuum (~400 to ~750 nm), with an extinction ratio of more than 90% and a spectral power density of 15 muW nm-1. Each optical MEMS element from the array can be switched asynchronously at a selected frequency performing both the spatial selection and the frequency modulation of a specific narrow spectral region. The method we describe allows the spectral and/or temporal and polarization encoding of the selected spectral bands and may find extensive applications in biomedical research.
Abstract Ophthalmologic manifestations occur in various inborn errors of metabolism (IEM), including small molecule disorders and organelle disorders. In a minority of diseases the occurrence of eye ...abnormalities could be attributed to direct toxic mechanisms of abnormal metabolic products or accumulation of normal metabolites by errors of synthetic pathways or by deficient energy metabolism. The age of onset of ocular abnormalities in IEM is variable, but onset often begins from birth to childhood. The major IEM associated with eye abnormalities include errors of lipid metabolism, carbohydrate metabolism, protein metabolism, and metal metabolism. IEM disorders with ocular motor manifestations include lipid storage diseases, neurotransmitter disorders and respiratory chain disorders. The purpose of this article is to describe ocular phenotypes associated with IEM, focusing on those diseases in which the ocular involvement is seen relatively early in the course of the disease. As therapeutic approaches become available for certain groups of IEM, the need for early diagnosis is increasingly important.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
One of the main noise sources for future interferometric gravitational wave detectors will be the thermal fluctuations of the mirrors used as test masses. To reduce the effect of this noise without ...changing the mirror material, size and temperature, the use of Laguerre-Gauss (LG) modes has been proposed. In this work we report the first experimental results obtained with a Fabry-Perot Michelson interferometer operated with Laguerre-Gauss LG sub(33) as input mode and developed as a table-top prototype to test alignment and matching procedures, possible control issues and optical performances of the LG sub(33). Among the results obtained, we have demonstrated the degradation of the interferometer contrast of the LG sub(33) with respect to the Gaussian beam, predicted by several previous simulations works and due to the degeneracy of LG modes having the same order. In addition, the observed contrast degradation for the LG sub(33) as well as the interferometer optical properties have been explained using a numerical simulation.
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