An optical arrangement for use in optical microscopy

An optical arrangement for reflected dark-field microscopy, comprising:

• a reflector of a first refractive index, the reflector comprising an input end configured to receive illumination light and an output end from which the illumination light exits the reflector after propagating therein;
• wherein the reflector comprises at least one reflective outer surface configured to reflect the illumination light internally within the reflector such that the reflected illumination light is angled in an inward direction towards a sample;
• and
• an observed medium of a second refractive index, the observed medium configured to be in direct contact with the output end of the reflector and with the sample such that the illumination light passes from the reflector through the observed medium to the sample without passing through another material with a refractive index lower than the second refractive index;
• wherein the second refractive index is lower than the first refractive index
• so that the sample is illuminated with the illuminating light with a NA higher than 1.