Design of pre-optics for laser guide star wavefront sensor for the ELT

Abstract In the present paper, we consider the optical design of a zoom system for the active refocusing in laser guide star wavefront sensors. The system is designed according to the specifications coming from the Extremely Large Telescope (ELT)-HARMONI instrument, the first-light, integral field spectrograph for the European (E)-ELT. The system must provide a refocusing of the laser guide as a function of telescope pointing and large decentring of the incoming beam. The system considers four moving lens groups, each of them being a doublet with one aspherical surface. The advantages and shortcomings of such a solution in terms of the component displacements and complexity of the surfaces are described in detail. It is shown that the system can provide the median value of the residual wavefront error of 13.8–94.3 nm and the maximum value <206 nm, while the exit pupil distortion is 0.26–0.36% for each of the telescope pointing directions.

[1]  R. Muradore,et al.  GALACSI system design and analysis , 2012, Other Conferences.

[2]  Bertrand Koehler,et al.  The E-ELT program status , 2016, Astronomical Telescopes + Instrumentation.

[3]  T. Fusco,et al.  The adaptive optics modes for HARMONI: from Classical to Laser Assisted Tomographic AO , 2016, Astronomical Telescopes + Instrumentation.

[4]  Miss A.O. Penney.  (b) , 1974, The New Yale Book of Quotations.

[5]  Johan Kosmalski,et al.  The E-ELT first light spectrograph HARMONI: capabilities and modes , 2016, Astronomical Telescopes + Instrumentation.

[6]  Sarah Kendrew,et al.  Simulating observations with HARMONI: the integral field spectrograph for the European Extremely Large Telescope , 2014, Astronomical Telescopes and Instrumentation.

[7]  Foreman Jw.  Simple numerical measure of the manufacturability of aspheric optical surfaces. , 1986 .

[8]  Ronald Holzlöhner,et al.  Statistics of the sodium layer parameters at low geographic latitude and its impact on adaptive-optics sodium laser guide star characteristics , 2010 .

[9]  Zach DeVito,et al.  Opt , 2017 .

[10]  N. S. Barnett,et al.  Private communication , 1969 .

[11]  Dan Zhu,et al.  Applying slope constrained Qbfs aspheres for asphericity redistribution in the design of infrared transmission spheres. , 2015, Applied optics.

[12]  Mark Casali,et al.  AO WFS detector developments at ESO to prepare for the E-ELT , 2016, Astronomical Telescopes + Instrumentation.

[13]  Douglas M. Summers,et al.  The W. M. Keck Observatory Laser Guide Star Adaptive Optics System: Performance Characterization , 2006 .

[14]  Andrew G. Glen,et al.  APPL , 2001 .

[15]  Paul Hickson,et al.  High resolution mesospheric sodium properties for adaptive optics applications , 2014 .

[16]  Lin Li,et al.  Applying slope constrained Q-type aspheres to develop higher performance lenses. , 2011, Optics express.

[17]  Eleazar R. Carrasco,et al.  Science readiness of the Gemini MCAO System: GeMS , 2012, Other Conferences.

[18]  Christian du Jeu.  Criterion to appreciate difficulties of aspherical polishing , 2004 .

[19]  G. Forbes,et al.  Shape specification for axially symmetric optical surfaces. , 2007, Optics express.

[20]  Pascal Jagourel,et al.  ATLAS: the E-ELT laser tomographic adaptive optics system , 2010, Astronomical Telescopes + Instrumentation.