Abstract: A re-scan optical system comprises a scanning element; first optical elements directing light onto the scanning element to provide scanning illumination light; second optical elements directing the scanning illumination light towards a sample, and directing captured sample light onto the scanning element providing descanned sample light; third optical elements directing at least part of the descanned sample light back onto the scanning element to provide rescanning sample light; and fourth optical elements directing the rescanning sample light towards an imaging system. The third optical elements define a first beam segment of the descanned beam path and a second beam segment of the descanned beam path. The fourth optical elements define a third path segment from the scanning element between the first and second beam path segments and/or from the scanning element at an enclosed angle with the scanned sample light path in a range of 80-100 degrees.