Methods and apparatus for high resolution imaging with reflectors at staggered depths beneath sample

A method comprising:

• (a) illuminating a sample in such a way that light travels from an active light source to a sample, passes through the sample, reflects from a set of reflectors, passes through the sample again and travels to a light sensor;
• and
• (b) measuring light incident on the light sensor;
• wherein
• (i) the reflectors in the set are each located at a different depth,
• (ii) light reflecting from each reflector in the set travels a different round-trip distance than, and is in the measuring measured separately from, light reflecting from any other reflector in the set,
• (iii) the active light source and the light sensor are included in an imaging system, which imaging system has an Abbe X-Y Resolution, and
• (iv) the light sensor has a spatial resolution, in x- and y-dimensions, that is smaller than the Abbe X-Y Resolution.

An imaging system comprising:

• (a) an active light source;
• (b) a set of reflectors;
• and
• (c) a light sensor;
• wherein
• (i) each reflector is at a different depth than is any other reflector in the set,
• (ii) the imaging system is configured in such a way that, when the system illuminates a sample
• (A) light travels from the active light source to the sample, passes through the sample, reflects from the set of reflectors, passes through the sample again and travels to the light sensor, and
• (B) light reflecting from each reflector in the set travels a different round- trip distance than, and arrives at the light sensor at a different time or with a different phase than, and is measured by the imaging system separately from, light reflecting from any other reflector in the set,
• (iii) the imaging system has an Abbe X-Y Resolution, and
• (iv) the light sensor has a spatial resolution, in x- and y-dimensions, that is smaller than the Abbe X-Y Resolution.