Optical angle measurement

An optical detector comprising:

• a periphery having a plurality of slit apertures at least two of which are oriented orthogonally to each other;
• a substrate having an epitaxial layer receiving light passing through each of the slit apertures;
• and
• a set of electrodes associated with each slit aperture, each electrode in each set arranged in the epitaxial layer to detect a quantity of the received light passing through the respective slit aperture, wherein the epitaxial layer has a continuous surface at least for each set of electrodes that encompasses the electrodes in each respective set of electrodes;
• wherein one of the set of electrodes is:
• (a) positioned at a shallower depth in the epitaxial layer than other electrodes of the set of electrodes and (b) aligned with respect to the slit aperture corresponding to the one of the set of electrodes to receive the light passing through the respective slit aperture.

A method comprising:

• identifying a proportion of incident light detected at a plurality of electrodes in an epitaxial layer having a continuous surface encompassing each of the electrodes after the incident light passes through an aperture;
• and
• calculating positional information of the incident light from the identified proportion of incident light detected at the plurality of electrodes;
• wherein one of the plurality of electrodes is:
• (a) positioned at a shallower depth in the epitaxial layer than other ones of the plurality of electrodes and (b) aligned with respect to the aperture to receive the light passing through the aperture.