Annular optical device

An annular optical device (100), comprising:

• an annular meso-optic (1) including an annulus (11) centered about an axis of revolution (A);
• and
• a secondary optical structure (2) substantially coaxial within the annulus (11) of the annular meso-optic (1), wherein the secondary optical structure (2) and the annular meso-optic (1) are separated by a media (12) including a media refractive index that is lower than a secondary optical structure refractive index, with the secondary optical structure (2) being configured to hold a specimen to be radiated by impinging electromagnetic radiation directed into the secondary optical structure (2) substantially along the axis of revolution (A), wherein scattered radiation from the secondary optical structure (2) and within the annulus (11) of the annular meso-optic (1) is allowed into the annular meso-optic (1) by the secondary optical structure (2) if an angle of incidence of the scattered radiation exceeds a predetermined incidence threshold and wherein the annular meso-optic (1) re-directs the scattered radiation to comprise re-directed radiation that is substantially parallel to the axis of revolution (A).