An apparatus for super-resolution fluorescence-microscopy imaging of a sample, the apparatus comprising: an objective lens having a forward field of view, the objective lens being arranged to collect light emanating from the sample within the forward field of view; a processing arrangement arranged to perform super-resolution fluorescence-microscopy imaging of the sample with the collected light; a waveguide component located forwards of the objective lens and arranged to (i) receive input light from outside the field of view, and (ii) use total internal reflection within the waveguide component to direct excitation light onto the sample; and an electronic optical-path control system arranged to: cause input light of a first wavelength to follow, at a first time, a first optical path corresponding to a first optical mode within the waveguide component, so as to illuminate the sample with a first excitation pattern; and cause input light of said first wavelength to follow, at a second time, a second optical path corresponding to a second optical mode within the waveguide component, wherein the second time is different from the first time, and wherein the second optical mode is different from the first optical mode, so as to illuminate the sample with a second excitation pattern, different from the first excitation pattern. an objective lens having a forward field of view, the objective lens being arranged to collect light emanating from the sample within the forward field of view; a processing arrangement arranged to perform super-resolution fluorescence-microscopy imaging of the sample with the collected light; a waveguide component located forwards of the objective lens and arranged to (i) receive input light from outside the field of view, and (ii) use total internal reflection within the waveguide component to direct excitation light onto the sample; and an electronic optical-path control system arranged to: cause input light of a first wavelength to follow, at a first time, a first optical path corresponding to a first optical mode within the waveguide component, so as to illuminate the sample with a first excitation pattern; and cause input light of said first wavelength to follow, at a second time, a second optical path corresponding to a second optical mode within the waveguide component, wherein the second time is different from the first time, and wherein the second optical mode is different from the first optical mode, so as to illuminate the sample with a second excitation pattern, different from the first excitation pattern. cause input light of a first wavelength to follow, at a first time, a first optical path corresponding to a first optical mode within the waveguide component, so as to illuminate the sample with a first excitation pattern; and cause input light of said first wavelength to follow, at a second time, a second optical path corresponding to a second optical mode within the waveguide component, wherein the second time is different from the first time, and wherein the second optical mode is different from the first optical mode, so as to illuminate the sample with a second excitation pattern, different from the first excitation pattern.