  Modifications to General Relativity (GR) often incorporate screening
mechanisms in order to remain compatible with existing tests of gravity. The
screening is less efficient in underdense regions, which suggests that cosmic
voids can be a useful cosmological probe for constraining modified gravity
models. In particular, weak lensing by voids has been proposed as a promising
test of such theories. Usually, voids are identified from galaxy distributions,
making them biased tracers of the underlying matter field. An alternative
approach is to study voids identified in weak lensing maps -- weak lensing
voids -- which have been shown to better correspond to true underdense regions.
In this paper, we study the ability of weak lensing voids to detect the
signatures of modified gravity. Focusing on the void abundance and weak lensing
profiles, we find that both statistics are sensitive probes of gravity. These
are quantified in terms of the signal-to-noise ratios (SNR) with which an
LSST-like survey will be able to distinguish between different gravity models.
We find that the tangential shear profiles of weak lensing voids are
considerably better than galaxy voids at this, though voids have somewhat lower
SNR than weak lensing peaks. The abundances of voids and peaks have
respectively $\rm{SNR} = 50$ and $70$ for a popular class of modified gravity
in an LSST-like survey.
