Posted by
Ian Dobbie on
URL: http://confocal-microscopy-list.275.s1.nabble.com/3D-structured-illumination-microscopy-with-an-axially-moving-illumination-pattern-tp7587343p7587346.html
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Reto Fiolka <
[hidden email]> writes:
> You are correct that for Sara's Multifocus SIM you would need axial
> phase steps to unmix the axial information components. A conventional
> grating based setup can not do that (it would need to shift the
> grating axially over large distances in image space or have a phase
> shifting element for the zero diffraction order). Therefore a proper
> 3D reconstruction was not attempted in that work.
In traditional 3-beam £D SIM you can phase step any of the 3 beams
relative to the other two to shift the pattern axially. If you step the
central one then you just shift the pattern axially. If you shift
either of the two outer beams you shift both axially and
laterally. On the OMX Blaze setup, you focus the stripes pattern with
the exact objective focal plane by shifting one beam relative to the
other two.
> Such a system has to my best knowledge not been realized yet, but
> would unlock the full potential of multifocus 3D SIM.
It ought to be possible to collect a data set of this type on an OMX
Blaze, although the current software will not do it. The reconstruction
would also need a bit of work as you would need to fit the starting
phase for each Z position of the pattern, or calculate how the phase
shifts as you shift the pattern in Z.
> PS: an interesting situation occurs if you shift the axial
> illumination pattern at a different rate than you make z steps in a
> normal 3D SIM microscope. The axial information, while being the same
> Fourier coefficients, would be shifted to other areas in 3D Fourier
> space than what the normal self demodulation would do.
Isn't this in effect what the Abrahamsson multi focus device does?
Ian