Optical random access memory

Claim 1

An electro optical memory arrangement which comprises a source of light at a first predetermined wavelength λ 1 ; an optical switch for selectively passing the light at said first wavelength along a predetermined optical path; a photochromic memory plate positioned across said optical path and having a multiplicity of memory cells thereon in an array disposed in two orthogonal directions, said plate carrying a stabilized film of bacteriorhodopsin whose molecules assume a first, ground state under influence of light of a given second wavelength λ 2 and assume a second, excited state under influence of light of said first wavelength λ 1 , said bacteriorhodopsin absorbing a relatively high amount of the light of said first wavelength when in said first state and a relatively low amount of the light of said first wavelength when in said second state; optical beam steering means disposed on said optical path in advance of said photochromic memory plate for selectively deflecting said light of said first wavelength on said optical path to a selected one of said memory cells; photodetector means in said optical path after said photochromic memory plate sensitive to light of said first wavelength λ 1 and producing an output which is of one binary sense or of an opposite, complementary binary sense depending on the strength of light of said first wavelength λ 1 reaching said photodetector means from said selected memory cell; means controlling the strength of the light from said source to pass the light of said first wavelength λ 1 , at a greater strength for a write cycle and at a significantly lesser strength for a read cycle; and reset illumination means for controllably illuminating the memory plate with light of said second wavelength λ 2 , to set said memory cells into said first state.