Minimizing the influence of higher-order transverse modes on the precision of cavity ring-down measurements

•It is experimentally found that the excitation of higher-order transverse modes degrades the precision of cavity ring-down (CRD) measurements.•Simple measures such as mode-matching optics, aperture, and trigger threshold are used to minimize the influence of higher-order mode excitation on CRD measurement precision.•Less than 0.2ppm uncertainty in reflectance measurement with CRD was obtained.