Optics and passive components
INAF groups (involved in radio astronomy and CMB studies) have a leadership role, acknowledged at an international level (ESA, NASA, ESO), in the design, modeling and measurement of complex optics. The leadership should be maintained and increased sothat national industries can benefit.
In current receivers the optical interface system needs to supply a wide instantaneous bandwidth (typically greater then 20%), to allow a continuous frequency coverage, good polarisation purity, as well as keeping weight and volume to a minimum (important both for space missions and cryogenic considerations). The need for an ever-growing range of frequencies translates into a need for high mechanical precision, obtainable withelectromoulding techniques.
Italy has a great deal of experience in this area. Collaborations between INAF, university institutes and small businesses have made use of know-how and development tools in electromagnetic optics and the associated simulations. Know-how related to the development of these components is subject to the transfer of technology towards industry for small scale component production (feeds, polarisers, guide filters, connectors) atfrequencies to about 200 GHz. This expertise has been used both for receivers mounted on Italian radio telescopes and, for example, ALMA, the Atacama Large Millimeter Array.
In fact, as part of ESO's responsibility to contribute to the antennas, the ALMA collectorsare being supplied by Media Lario Technologies, born as a spin-off from INAF institutes for the construction of mirrors for the XMM X-ray mission. The experience of certain INAFinstitutions in optics destined for space systems should also be mentioned, due to its relevance in a Sixth Framework Programme concerning "feedles" array receivers, in which the formation of the beam is achieved electronically at the focal plane.
