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Diffstat (limited to 'axial/w_.m')
| -rw-r--r-- | axial/w_.m | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/axial/w_.m b/axial/w_.m new file mode 100644 index 0000000..6d4a2d4 --- /dev/null +++ b/axial/w_.m @@ -0,0 +1,23 @@ +%---------------------------------------------------------------
+% Returns the beam width given the q factor and wavelength
+% of a Gaussian beam. Note that q and lambda are assumed
+% to have the same units.
+%
+% SYNTAX: w=w_(q <,lambda>);
+%
+% 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: w=w_(q <,lambda>);
+%---------------------------------------------------------------
+
+function wout=w_(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));
+
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