Photonic technologies in astronomical instruments

Astronomy Unit Seminars
Dr. Itan Gris Sanchez (U. Bath)
Guillem Anglada
February 20th, 2015 at 14:30
GO Jones Room 610

Specialty multicore fibres and integrated photonic devices, like the so-called photonic lantern and ultrafast inscribed glass chips, are opening possibilities in astronomical instrumentation. For example they can act as new types of fibre relays (between the telescope and the spectrograph) to reduce modal noise, limit FRD, capture more light and even reformat the light pattern to a suitable shape. By inscribing Bragg gratings into the cores of these fibres, they can also be used to filter the narrow OH emission lines originating in the earth's atmosphere. We use the concept of light modes to describe how light travels in the fibre and how it can be controlled through the waveguide’s material and geometry. We can design and construct the fibre (and post process it to make photonic lanterns) to give it the characteristics needed for a particular experiment or application for example to match the wavelength of operation, numerical aperture (f/#), number of modes and spot size.