UV Photonic-Integrated-Circuits-Based Structured Illumination Microscopy With a Field of View Larger than $100\,\mu \text{m}^{2}$

Photonic integrated circuits (PICs) are expected to add practicality and new functionalities in a considerable number of optical applications, including optical microscopy. Here, we present a PIC design allowing a far-field structured UV illumination pattern with a fringe period as low as
$\text{370}\,\text{nm}$
, a fringe visibility of 0.83 over field of views of more than
$150\,\mu \text{m}\,\times 200\,\mu \text{m}$
and a radiant intensity as large as
$\text{0.49}\,\text{mW}$
. The circuits include single mode waveguides with propagation losses of
$\text{3}\,\text{dB/cm}$
at a wavelength
$\lambda =360\,\text{nm}$
, two diffraction gratings for beam shaping out of the chip plane, a beam splitter and a phase shifter. Using fluorescent gratings with pitches longer or shorter than the wavelength, as control objects, and a collecting lens with a numerical aperture of 0.5, the current PICs enable to highlight experimentally the Moiré pattern at the heart of the optical resolution enhancement and to achieve a doubling of the optical resolution in the direction of the illumination.