% Mirror is a type of Optic used in Optickle
%
% obj = Mirror(name, aio, Chr, Thr, Lhr, Rar, Lmd, Nmd)
%
% Optical Paramters:
% aio - angle of incidence (in degrees)
% Chr - curvature of HR surface (Chr = 1 / radius of curvature)
% Thr - power transmission of HR suface
% Lhr - power loss on reflection from HR surface
% Rar - power reflection of AR surface
% Nmd - refractive index of medium (1.45 for fused silica, SiO2)
% Lmd - power loss in medium (one pass)
%
% default optical parameter values are:
% [aio, Chr, Thr, Lhr, Rar, Lmd,  Nmd]
% [  0,   0,   0,   0,   0,   0, 1.45]
%
% Chr is the mirror "curvature" which is the inverse of the radius
% of curvature (c = 1/roc = 1/(2 * f), where f is the focal length).
% Positive curvatures are used for concave, zero for a flat mirror,
% and negative values for convex mirrors.
% 
% Note that the three loss mechanisms (Lhr, Rar and Lmd) have default
% values of zero.  Non-zero values will result in the entrance of
% vacuum fluctuations, with a corresponding increase in quantum noise,
% and an increase in time required to compute quantum noise.
%
% A mirror has 2 inputs and 4 outputs.
% Inputs:
% 1, fr, HR = front (HR side)
% 2, bk, AR = back (AR side)
%
% Outputs:
% 1, fr = front
% 2, bk = back
% 3, pi = pick-off sampling back input
% 4, po = pick-off sampling back output
%
%% Example: a curved input mirror with 3km radius and 1% transmission
% obj = Mirror('ITMX', 0, 1/3e3, 0.01);

function obj = Mirror(varargin)

  obj = struct('aoi', [], 'Chr', [], 'Thr', [], 'Lhr', [], ...
    'Rar', [], 'Lmd', [], 'Nmd', [], 'dWaist', []);

  obj = class(obj, 'Mirror', Optic);

  errstr = 'Don''t know what to do with ';	% for argument error messages
  switch( nargin )
    case 0					% default constructor, do nothing
    case {1 2 3 4 5 6 7 8}
      % copy constructor
      arg = varargin{1};
      if( isa(arg, class(obj)) )
        obj = arg;
        return
      end

      % ==== name, aoi, Chr, Thr, Lhr, Rar, Lmd, Nmd
      args = {'', 0, 0, 0, 0, 0, 0, 1.45};
      args(1:nargin) = varargin(1:end);
      
      % build optic
      inNames = {{'fr' 'HR'}, {'bk' 'AR'}};
      outNames = {{'fr' 'HR'}, {'bk' 'AR'}, {'pi'}, {'po'}};
      driveNames = {'pos'};
      obj.Optic = Optic(args{1}, inNames, outNames, driveNames);

      % store stuff in class
      [obj.aoi, obj.Chr, obj.Thr, obj.Lhr, ...
        obj.Rar, obj.Lmd, obj.Nmd] = deal(args{2:end});

    otherwise
      % wrong number of input args
      error([errstr '%d input arguments.'], nargin);
  end