Individually switched field emission arrays

An electron beam apparatus comprising:

• a substrate comprising an optically modulated current source;
• a plurality of field emitter elements disposed over the substrate in at least one array, each field emitter element of the plurality of field emitter elements comprising:
• a current channel region disposed at a first end of the field emitter element proximate to the optically modulated current source;
• and
• a field emitter tip disposed proximate to a second end of the field emitter element that is different from the first end;
• and
• at least one extraction gate electrode disposed proximate to the plurality of field emitter elements, to apply a potential difference proximate to at least one field emitter tip of the plurality of field emitter elements, thereby accelerating electrons emitted from the at least one field emitter tip in a direction away from the at least one field emitter tip;
• wherein the optically modulated current source is a P-I-N diode.

An electron beam apparatus comprising:

• a plurality of current source elements disposed in at least one array, each current source element of the plurality of current source elements comprising:
• a gated vertical transistor;
• an ungated vertical transistor;
• or
• a current controlled channel that is proximate to an optically modulated current source;
• a plurality of field emitter tips, each field emitter tip of the plurality of field emitter tips being coupled to an end of a respective current source element of the plurality of current source elements;
• and
• at least one extraction gate electrode disposed proximate to the plurality of current source elements, to apply a potential difference proximate to at least one field emitter tip of the plurality of current source elements, wherein the potential difference accelerates the electrons emitted by at least one field emitter tip of the plurality of field emitter tips in a direction away from the at least one field emitter tip.