  We present experimental demonstration of tilt-mirror assisted transmission
structured illumination microscopy (tSIM) that offers a large field of view
super resolution imaging. An assembly of custom-designed tilt-mirrors are
employed as the illumination module where the sample is excited with the
interference of two beams reflected from the opposite pair of mirror facets.
Tunable frequency structured patterns are generated by changing the mirror-tilt
angle and the hexagonal-symmetric arrangement is considered for the isotropic
resolution in three orientations. Utilizing high numerical aperture (NA)
objective in standard SIM provides super-resolution compromising with the
field-of-view (FOV). Employing low NA (20X/0.4) objective lens detection, we
experimentally demonstrate ~ (0.56mm x 0.35mm) size single FOV image with ~1.7-
and ~2.4-fold resolution improvement (exploiting various illumination by tuning
tilt-mirrors) over the diffraction limit. The results are verified both for the
fluorescent beads as well as biological samples. The tSIM geometry decouples
the illumination and the collection light paths consequently enabling free
change of the imaging objective lens without influencing the spatial frequency
of the illumination pattern that are defined by the tilt-mirrors. The large and
scalable FoV supported by tSIM will find usage for applications where scanning
large areas are necessary as in pathology and applications where images must be
correlated both in space and time.

Optics;Biological Physics