According to various embodiments, there is provided an imaging device including a Bessel beam generator configured to provide a Bessel beam; a scanning mirror configured to scan the Bessel beam across a two-dimensional plane; a scan lens configured to receive the Bessel beam from the scanning mirror, a centre of the scan lens being at least substantially a focal length of the scan lens away from the scanning mirror; an illumination tube lens configured to receive the Bessel beam from the scan lens, a centre of the illumination tube lens being at least substantially a sum of the focal length of the scan lens and a focal length of the illumination tube lens away from the centre of the scan lens; an illumination objective lens positioned in direct line-of-sight to a specimen, the illumination objective lens configured to receive the Bessel beam from the illumination tube lens and further configured to illuminate the specimen with the Bessel beam, wherein a centre of the illumination objective lens is at least substantially the focal length of the illumination tube lens away from the centre of the illumination tube lens; and a detection optics arrangement configured to receive a reflected beam (emitted fluorescence beam) from the specimen.