Background suppression with dual modulation by saturated absorption competition microscopy

•In this report, we propose a novel approach by simultaneously modulating the two beams of SAC with two distinct frequencies, called dual-modulation SAC (dmSAC).•In dmSAC modality, the homodyne detection would not identify the uncorrelated fluorescence, the image background could be free.•We have experimentally demonstrated the dependences of the background contribution on the modulation frequencies and spatial resolution as high as one seventh of the illumination wavelength is gained.•dmSAC is believed to hold great potential in biological and physical applications and to become another powerful tool for the study of the micro world through the follow-up researches.