1 files changed, 24 insertions, 0 deletions
diff --git a/axial/R_.m b/axial/R_.m
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index 0000000..1691656
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+%---------------------------------------------------------------
+% Returns the phasefront radius of curvature and the beam width
+% given the q factor of a Gaussian beam and the wavelength.
+%
+% SYNTAX: [R <,w>]=R_(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.
+% If w is requested as an output, lambda must be supplied.
+%
+%---------------------------------------------------------------
+% SYNTAX: [R <,w>]=R_(q,<,lambda>);
+%---------------------------------------------------------------
+
+function [Rout,wout]=R_(q,varargin)
+
+if nargin>=2, lambda=varargin{1}; else lambda=1064e-9; end
+
+wout=sqrt(lambda/pi .* imag(q).*(1+real(q).^2./imag(q).^2));
+Rout=real(q).*(1+imag(q).^2./real(q).^2).*ones(size(wout));
+\ No newline at end of file