From d1b62466d81b164656588ac1c55acff15ee9ea43 Mon Sep 17 00:00:00 2001
From: Eugeniy Mikhailov <evgmik@gmail.com>
Date: Tue, 13 May 2014 15:35:26 -0400
Subject: initial

The optics_toolkit code taken from
http://mercury.pr.erau.edu/~greta9a1/downloads/index.html

the older version is also available at mathwork web site
http://www.mathworks.com/matlabcentral/fileexchange/15459-basic-paraxial-optics-toolkit
---
 axial/L_.m | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 axial/L_.m

(limited to 'axial/L_.m')

diff --git a/axial/L_.m b/axial/L_.m
new file mode 100644
index 0000000..351af31
--- /dev/null
+++ b/axial/L_.m
@@ -0,0 +1,23 @@
+%---------------------------------------------------------------
+% Given the q-factor and wavelength of a beam, this function
+% returns the position and size of the waist. 
+%
+% SYNTAX: [L <,w0>]=L_(q <,lambda>);   
+%            <...> indicates optional arguments
+%
+% q      = q-factor of the beam at the position where R and w are to
+%          be found. q can be a vector
+% lambda = wavelength. Can be a vector or scalar.
+%
+% If both q and lambda are vectors, they must be the same size.
+%
+%---------------------------------------------------------------
+% SYNTAX: [L <,w0>]=L_(q <,lambda>);
+%---------------------------------------------------------------
+
+function [L,w0]=L_(q,varargin); 
+
+if nargin>=2, lambda=varargin{1}; else lambda=1064e-9; end
+
+w0=sqrt(-lambda/pi./imag(1./q));
+L=-real(q).*ones(size(w0));
\ No newline at end of file
-- 
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