Apparatus and method for carrying out analysis of samples

A method of conducting an optical inspection of a biological, chemical, or biochemical sample, the method comprising the steps of:

• supporting the sample on a substrate;
• supporting the substrate on a first side;
• directing a beam of electromagnetic radiation from a radiation source onto the substrate;
• scanning the beam over the substrate by rotating the substrate about an axis substantially perpendicular to the substrate and by moving the radiation source in a direction having a component radial to said axis;
• detecting radiation reflected from or transmitted through the substrate and sample and providing an output signal corresponding to the detected radiation;
• analyzing the output signal during the scanning step to extract from the output signal digital position address information arising from modulation of at least a part of the beam by distributed electromagnetic radiation modulating means provided on the substrate, so that the scan is aligned relative to the substrate;
• arranging reflecting means on a second side of the substrate, said reflecting means including said distributed electromagnetic radiation modulating means;
• and
• directing said beam of electromagnetic radiation onto a second side of the sample and detecting radiation reflected from the second side and through the substrate and exiting therefrom through a first side wherein analysis of the reflected radiation provides said address information and analysis of the second beam provides information on the sample to the inspected.