PHASE PLATES & GRATINGS
SILIOS designs and manufactures Phases Plates and Gratings to address several need in Astronomy and Space :
- Atmospheric Turbulence Phase Screens
- Large multilevel curved gratings of GRISMs
- Piston Plates
- Coronography Phase Plates
TURBULENCE PHASE SCREENS
Phase Screens are transmitting or reflecting optical elements whose surfaces present an encoded bi-dimensional aberration. The encoded phase map is a spatial distribution typical of atmospheric turbulence. A plane wavefront passing through or reflected, emerges distorted according to the encoded aberrations.
SILIOS supplied the very first worldwide fused silica screens (32 and 64 phase levels) in 2004 to ESO for the VLT instruments.
LARGE MULTILEVEL CURVED GRATINGS
SILIOS proposes resin-free blazed and curved gratings. The gratings are manufactured using cumulative etching method onto fused silica substrates. The component are resin-free, only composed of fused silica.
SILIOS supplies uniform and high efficiency gratings. SILIOS’ technology allows manufacturing and supplying very high optical performances onto large gratings (high transmitted efficiency, low RMS wavefront error, groove shape and roughness highly uniform over the full clear aperture)
SILIOS supplied a series of large gratings to be integrated in the NISP (Near Infrared Spectro-Photometer) instrument of the EUCLID space mission (ESA).
Since the invention of the telescope by Issac Newton in the 17th century, the size of the mirrors has been ever increasing. During the 20th century, the diameters increased from 2 meters up to 10 meters. To reach larger diameters (tens of meters), mirrors have now to be segmented. All the segments have to be accurately aligned from one to each other.
Several methods of alignement are under test using piston plates as mirror simulators. SILIOS supplied plates with nano-steps.
CORONOGRAPHY PHASE PLATES
Coronography technics are used in the field of exo-planet detection and study. First coronograph was imagine and built in the beginning of 1930's by Bernard Lyot. He used an amplitude diaphragm installed in his telescope. In 1997, Claude and François Roddier invent the phase mask coronograph. Since then, several different designs have been imagined giving ever higher performances (single and dual zone, four quadrants).
SILIOS provided a wide range of phase plates geometries.