Fitting Measured Beam Data
==========================

Extracting waist size and position from measured beam analyzer data is simple. The script expects a data file containing the measurement position (in cm) as first column, and the saggital/tangential beam diameter (:math:`1/e^2` value, ie. 13.5%) in µm, as follows::

    # position [cm], diameter X [µm], diameter Y [µm]
    77.5    939 857
    97.5    964 887
    107.5   982 954
    117.5   1015    1036
    132.5   1064    1190
    ...

With this file, you can then run:

    >>> %pylab inline
    >>> from nqlab import *
    >>> analysis.fit_beam_data('measurement.dat', wavelength=1064e-9)

... to obtain a nice plot:

.. image:: _static/fit_beam_data.png
    :width: 500

.. note:: If your file is separated by commas instead of tabs, specify the additional option :code:`separator=','`. Otherwise, you will get a strange *TypeError* ("cannot perform __mul__ ...").

For a full list of available options, see :func:`nqlab.analysis.gaussian_beam.fit_beam_data`.