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The European Space Agency's space-based Darwin mission aims to directly detect extrasolar Earth-like planets using nulling interferometry. However, in order to accomplish this using current optical technology, the interferometer input beams must be filtered to remove local wavefront errors. Although short lengths of single-mode fiber are ideal wavefront filters, Darwin's operating wavelength range of 4 - 20 microm presents real challenges for optical fiber technology. In addition to the fact that step-index fibers only offer acceptable coupling efficiency over about one octave of optical bandwidth, very few suitable materials are transparent within this wavelength range. Microstructured optical fibers offer two unique properties that hold great promise for this application; they can be made from a single-material and offer endlessly single-mode guidance. Here we explore the advantages of using a microstructured fiber as a broadband wavefront filter for 4 - 20 microm.

This paper describes the development, characterisation and environmental testing of a high performance state-of-the-art optical filter for separating the Mie and Rayleigh backscatter signals for the ATLID LIDAR of the EarthCARE mission. The filter assembly utilises capacitance stabilised Fabry-Pérot étalon technology to provide high resolution optical filtering of the LIDAR signal, efficiently separating the two critical backscatter components from the atmosphere. The paper describes the development of the filter assembly and its subsequent performance testing. The filter has demonstrated state-of-the-art optical performance. Additionally, one of the étalons has been taken through complete environmental testing for space applications.

The paper deals with dependence between the parameters of laser microprocessing system, used to scribe a microchanel on the floppy disk magnetic layer, and the parameters of the channel caused "missing pulse" information error, generated while reading the disk.. The results are used to precise the laser microprocessing aimed to ensure the both precise microchanel and precise information pulse.

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