Rescan optical system, microscope and method

re-scan optical system is provided comprising a scanning element and first optical elements defining an incident illumination beam path to the scanning element for directing a beam of illumination light onto the scanning element to provide a scanning illumination light beam from the scanning element; second optical elements defining a scanning beam path for directing the scanning illumination light beam from the scanning element towards a sample and illuminating the sample thus causing sample light, and for directing a beam of captured sample light onto the scanning element to provide a descanned sample light beam from the scanning element; third optical elements defining a descanned beam path for directing at least part of the descanned sample light beam from the scanning element and back onto the scanning element to provide a rescanning sample light beam from the scanning element; and fourth optical elements defining a rescanning beam path for directing the rescanning sample light beam towards an imaging plane of an imaging system. In the system, the third optical elements define a first beam path segment of the descanned beam path extending from the scanning element and a second beam path segment of the descanned beam path extending to the scanning element. Further, the fourth optical elements define a third path segment extending from the scanning element between the first and second beam path segments and/or extending from the scanning element (10) at an enclosed angle with the scanned sample light path in a range of 80-100 degrees.