  Wide-field lensfree on-chip microscopy, which leverages holography principles
to capture interferometric light-field encodings without lenses, is an emerging
imaging modality with widespread interest given the large field-of-view
compared to lens-based techniques. In this study, we introduce the idea of
laser light-field fusion for lensfree on-chip phase contrast nanoscopy, where
interferometric laser light-field encodings acquired using an on-chip setup
with laser pulsations at different wavelengths are fused to produce marker-free
phase contrast images of superior quality with resolving power more than five
times below the pixel pitch of the sensor array and more than 40% beyond the
diffraction limit. As a proof of concept, we demonstrate, for the first time, a
wide-field lensfree on-chip instrument successfully detecting 300 nm particles,
resulting in a numerical aperture of 1.1, across a large field-of-view of
$\sim$ 30 mm$^2$ without any specialized or intricate sample preparation, or
the use of synthetic aperture- or shift-based techniques.
