Rayon lumineux

Résumé

vignette|Lasers visibles Lasers rouges : 635 nm, 660 nm Lasers verts : 520 nm, 532 nm Lasers bleus : 405 nm, 445 nm Le rayon lumineux est une notion d'optique et un outil mathématique, utilisé principalement en optique géométrique, décrivant le trajet de la lumière de manière simplificatrice, valable uniquement lorsque le rayon lumineux se propage dans des milieux où les obstacles et composants optiques ont des dimensions très supérieures à la longueur d'onde. Un rayon lumineux n'a pas d'existence physique réelle et représente le cas idéal où il serait possible de sélectionner un faisceau parallèle infiniment fin de lumière. Une manière d'approcher la notion de rayon lumineux par l'expérience est l'utilisation d'un laser dont le faisceau est très fin ou d'un pinceau très fin de lumière collimatée. Histoire de la notion L'histoire des rayons lumineux suit celle du développement de l'optique géométrique, ayant servi de principal support mathématique à

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https://fr.wikipedia.org/wiki/Rayon_lumineux

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MEASURING THE BUNCH FREQUENCY MULTIPLICATION AT CTF3

Daniel Egger

The CLIC Test Facility 3 (CTF3) is being built and commissioned by an international collaboration to test the feasibility of the proposed Compact Linear Collider (CLIC) drive beam generation scheme. Central to this scheme is the use of RF deflectors to inject bunches into a delay loop and a combiner ring, in order to transform the initial bunch frequency of 1.5 GHz from the linac to a final bunch frequency of 12 GHz. The optimization procedure relies on several steps. The active length of each ring is carefully adjusted to within less than millimeter accuracy using a wiggler magnet. The transverse optics of the machine must be set up in a way to ensure beam isochronicity. Diagnostics based on optical Streak camera and RF power measurements have been designed to measure the longitudinal behavior of the beam during the combination. This paper presents their performance and recent measurements.

2010

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A part of the beam losses at transition crossing of high intensity beams in the CERN PS have been attributed to an excursion of the closed orbit. The orbit jump occurs simultaneously with the jump of the transition energy triggered by pulsed quadrupoles. Investigations showed that the position of the pickups used for the radial loop system was not optimized with respect to the dispersion change caused by the fast change of the transition energy. Thanks to new electronics of the orbit measurement system, turn-by-turn orbit data could be recorded around transition crossing. Their analysis, together with calculations of the transverse optics, allowed determining a new choice of pickup positions for the radial loop. In comparison to the previous pickup configuration, the new configuration improves the mean radial position not only during transition crossing, but all along the acceleration cycle.

2010

Chargement

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We investigate the transition of optical regimes of miniaturized optical systems using two canonical examples, where the refraction of light limits the system performance. A ball-lens and a solid immersion lens (SIL) are considered, whose refractive responses can be intuitively described by ray optics when the system size is relatively large. For miniaturized systems, the optical response differs from that of conventional large systems. Since such new responses occur when the refractive response of light start to disappear, this boundary is called the refraction limit. Our intension is to bring insights into new phenomena beyond such a boundary.. First, the refraction limit of the ball-lens is identified with three different criteria: the focal length, the spot size, and the amount of depolarization. The light confinement effect of nanoscale SILs, which have an intentionally deformed shape, demonstrates the diminishing effect of the refractive response of light. Likewise, beyond the refraction limit of the miniaturized systems, the signature of refractive degradations vanishes, and the shape errors of elements become negligible.

Spie-Int Soc Optical Engineering2016

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