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We report the discovery of five new doubly-imaged lensed quasars from thefirst 2500 square degrees of the ongoing Canada-France Imaging Survey (CFIS),which is a component of the Ultraviolet Near Infrared Optical Northern Survey(UNIONS), selected from initial catalogues of either Gaia pairs or MILLIQUASquasars. We take advantage of the deep, 0.6'' median-seeing $r$-band imaging ofCFIS to confirm the presence of multiple point sources with similar colour of$u-r$, via convolution of the Laplacian of the point spread function. Requiringsimilar-colour point sources with flux ratios less than 2.5 mag in $r$-band,reduces the number of candidates from 256314 to 7815. After visual inspectionwe obtain 30 high-grade candidates, and prioritise spectroscopic follow-up forthose showing signs of a lensing galaxy upon subtraction of the point sources.We obtain long-slit spectra for 18 candidates with ALFOSC on the 2.56-m NordicOptical Telescope (NOT), confirming five new doubly lensed quasars with$1.21<z<3.36$ and angular separations from 0.8'' to 2.5''. One additionalsystem is a probable lensed quasar based on the CFIS imaging and existing SDSSspectrum. We further classify six objects as nearly identical quasars -- stillpossible lenses but without the detection of a lensing galaxy. Given ourrecovery rate ($83\%$) of existing optically bright lenses within the CFISfootprint, we expect that a similar strategy, coupled with $u-r$colour-selection from CFIS alone, will provide an efficient and completediscovery of small-separation lensed quasars of source redshifts below $z=2.7$within the CFIS $r$-band magnitude limit of 24.1 mag.

Discovery of Strongly Lensed Quasars in the Ultraviolet Near Infrared Optical Northern Survey (UNIONS)