Name: Annu Jacob
Affiliation: Inter-University Centre for Astronomy and Astrophysics, Pune, India
Conference ID : ASI2022_603
Title : DOTIFS Integral field unit manufacturing overview and associated IFU tests
Authors : Annu Jacob , A.N.Ramaprakash, Chaitanya Rajarshi, Hillol Das, Pravin Khodade, Sabyasachi Chattopadhyay, Amitesh Omar
Abstract Type: Oral
Abstract Category : Instrumentation and Techniques
Abstract : Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS) is a new multi-object integral field spectrograph being built by the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, India for the 3.6m Devasthal Optical Telescope, (DOT). Spectrographs, which disperse the light to study various aspects of the source, traditionally follow long slit to enter the light into to the instrument. However, varying slit width, atmospheric dispersion, crowded object field etc, causes this approach to lose its efficiency. A 2D field access using optical fibres solves most of these issues and introduces additional modularity. However, the circular shape of the fibre tip causes light loss as the fill factor <80%. There are mainly two ways to solve these issues, one is with 2D field splicers which are usually mirrors which break the field and reflect the beams in different directions, the other a more convenient alternative is using micro lens arrays (MLA) coupled with optical fibres, increasing the fill factor>90%. Even with this advantage, the miss alignment of the optical fibre with the MLA can cause increase in optical entropy and hence loss of effective transmission. Therefore, making a precise fiber to micro-lenslet array holder is a necessity. In DOTIFS which uses a combination of MLA and fibers to transmit the light, the IFU unit of the spectrograph consist of fiber array held on a mask and glued to a micro lenslet array. In this paper we present dry etching based fibre holder manufacturing for holding the fibres of IFU of DOTIFS spectrograph. We present an over view on design , manufacturing and gluing and polishing concepts for fibre holder and the tests and results on the IFU system.