  We report non-destructive imaging of optically trapped calcium monofluoride
(CaF) molecules using in-situ $\Lambda$-enhanced gray molasses cooling. $200$
times more fluorescence is obtained compared to destructive on-resonance
imaging, and the trapped molecules remain at a temperature of
$20\,\mu\text{K}$. The achieved number of scattered photons makes possible
non-destructive single-shot detection of single molecules with high fidelity.
