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Entry  Sat Mar 10 15:29:47 2012, Zach, HowTo, Computer Scripts / Programs, ModeMatchr MMrLogo.png
    Reply  Wed Mar 14 13:27:15 2012, Zach, HowTo, Computer Scripts / Programs, ModeMatchr 
Message ID: 6415     Entry time: Wed Mar 14 13:27:15 2012     In reply to: 6399
Author: Zach 
Type: HowTo 
Category: Computer Scripts / Programs 
Subject: ModeMatchr 

I have added to ModeMatchr the capability to fix the total MMT distance. This is nice if you are coupling to a cavity some fixed distance away. The blurb from the help:

% Note: for any total length constraint dtot_tol > 0, ModeMatchr will use
% fminsearch to find the best solutions near your nominal dtot, and then
% omit solutions whose dtot lie outside your tolerance. For dtot_tol = 0,
% ModeMatchr actively constrains dtot to your value, and then finds the
% best solution. Therefore, set dtot_tol = 0 if you have a fixed distance
% into which to put a MMT.

Quote:

For your mode matching pleasure, I have added a tool called "ModeMatchr" to the SVN under /trunk/zach/tools/modematchr/

It uses the usual fminsearch approach, but tolerates a fully astigmatic input (i.e., w0ix ≠ w0iy, z0ix ≠ z0iy) and allows for transforming to an elliptical waist  (i.e., w0fx ≠ w0fy, but z0fx = z0fy). It would be straightforward to allow for z0fx ≠ z0fy, but I have never seen a case when we actually wanted this. On the other hand, the elliptical output ability is nice for coupling to wide-angle ring cavities.

It also does the looping through available lenses for you , and retains the best solution for each lens combination in an output cell, which can then be combed with another function (getOtherSol). fminsearch is incredibly fast: with a 10-lens bank, it finds all 100 best solutions on my crappy MacBook in <10s.

I have also included the functionality to constrain the length of the total MMT to within some percentage of the optimal distance, which helps to sift through the muck .

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