Time of flight sensors with light directing elements

A time of flight sensor comprising:

• at least one demodulation pixel, each demodulation pixel comprising:
• a semiconductor substrate;
• a charge generation region in the semiconductor substrate, the charge generation region having a lateral extent, the charge generation region being configured to convert light into charge carriers;
• a light directing element in the charge generation region of the semiconductor substrate, the light directing element being configured to direct light through at least a portion of the lateral extent of the charge generation region, wherein the light directing element is a diffractive element with a multilayer structure of trenches filled with at least two vertically oriented layers of materials;
• a collection region in the semiconductor substrate, the collection region being configured to collect the charge carriers generated in at least a portion of the lateral extent of the charge generation region, and
• a readout component in electrical communication with the collection region, the readout component being operable to control an electrical coupling between the charge generation region and the collection region.