Photoconductive switch

A method of optically switching, the method comprising:

• providing a photoconductive switch comprising:
• a planar photoconductive material and
• first and second contacts provided on said photoconductive material,
• wherein said first and second contacts comprise a plurality of interdigitated tracks, the tracks of each contact being separated from the tracks of the other contact by a photoconductive gap, the tracks being arranged such that the minimum photoconductive gap measured in a first direction remains substantially similar regardless of the orientation of the first direction, and
• wherein said tracks are generally concentric and possess a high degree of rotational symmetry;
• and
• irradiating the switch to turn it on.