pysted.microscopes.DyMINMicroscope.get_effective

DyMINMicroscope.get_effective(datamap_pixelsize, p_ex, p_sted)

Computes the effective point spread function.

Defined here as the spatial map of time averaged detected power per molecule, taking the sted de-excitation, anti-stoke excitation and the detector properties (detection psf and gating) into account.

The technique follows the method and equations described in [Willig2006], [Leutenegger2010] and [Holler2011]. Notable approximations from [Leutenegger2010] include the assumption that the excitation pulse width is infinitely small and that the sted pulse is of perfect rectangular shape and starts at the beginning of the period. Also, a two energy levels (plus their vibrational sub-levels) with two rate equations is used. To include the vibrational decay dynamics (parametrized by the vibrational decay rate), an effective saturation factor is used.

To account for the detection gating, the bounds in the integral from [Leutenegger2010] eq. 3 were adjusted.

Anti-stokes excitation at the beginnning of the period was by added by modeling the sted beam as an infinitely small pulse, similarly to the excitation pulse. This leads to an underestimation of its effect on the detected signal, since excitation by the STED beam near the end of the STED beam, for example, would have less time to be depleted.

Parameters:

  • datamap_pixelsize – The size of one pixel of the simulated image (m).

  • p_ex – The time averaged power of the excitation beam (W).

  • p_sted – The power of the STED beam (W).

  • data_pixelsize – The size of one pixel of the raw data (m).

Returns:

A 2D array of the intensity (W/molecule)