Light modulator element

Abstract

A device for modulating and a nondestructive readout storage device employing modulation of light transmitted through an irregular ferroelectric crystal before and after the rotation of the vibration plane thereof caused by an applied electric field equal to or larger than the coercive field thereof.

We claim:  .[.1. A device for modulating a beam of light comprising a pair of light polarizer plates disposed substantially in parallel with each other and having their surfaces substantially perpendicular to the direction of incident light thereon an irreguar ferroelectric element having a pair of Z-cut planes, said irregular ferroelectric element being arranged between said pair of light polarizer plates in such a manner that said Z-cut planes of said element are substantially parallel to said light polarizer plates, a pair of transparent electrodes each provided on each of said pair of Z-cut planes, and means for applying an electric field not lower than the coercive field of said element across said element through said pair of transparent electrodes..]. .[.2. A device according to claim 1, further comprising a quarter wavelength plate for the central wavelength of white light..]. .[.3. A device according to claim 1, wherein said irregular ferroelectric material is a single crystal having molybdate gadolinium oxide structure represented by (R x  R' 11x ) 2  O 3 .3Mo 1-e  W c  O 3 , where R and R' are at least one element of the rare earths, x is a number of from 0 to 1.0, and e is a number of from 0 to 0.2..]. .[.4. A device according to claim 1, wherein each of said pairs of transparent electrodes comprises a plurality of parallel strips at equal intervals, said strips comprising oppositely biased electrodes crossing over substantially perpendicularly to each other..]. .[.5. A device according to claim 4, wherein said electrodes are made of one of SnO 3  and InO 2 ..]..Iadd. 6. A device for modulating a beam of light comprising: 
       a pair of light polarizer plates disposed substantially in parallel with each other; 
       an irregular ferroelectric element having a pair of Z-cut planes; 
       a pair of transparent electrodes each provided on each of said pair of Z-cut planes; and 
       means for applying an electric field not lower than the coercive field of said element across said element through said pair of transparent electrodes, said irregular ferroelectric element being made of molybdate gadolinium oxide crystal structure given by the formula   R.sub.2 O.sub.3 . 3 Mo.sub.1.sub.-e W.sub.e O.sub.3     
       where e is a number of from 0 to 0.2, and R is an element selected from the group consisting of Sm, Tb, Dy and Eu. .Iaddend. .Iadd. 7. A device for modulating a beam of light comprising: 
       a pair of light polarizer plates disposed substantially in parallel with each other; 
       an irregular ferroelectric element having a pair of Z-cut planes; 
       a pair of transparent electrodes each provided on each of said pair of Z-cut planes; and 
       means for applying an electric field not lower than the coercive field of said element across said element through said pair of transparent electrodes, said irregular ferroelectric element being made of molybdate gadolinium oxide crystal structure given by the formula   (R.sub.x R'.sub.1.sub.-x).sub.2 O.sub.3.3Mo.sub.1.sub.-e W.sub.e O.sub.3     
       where R is constituted by at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Dy, Eu, Tb, Tm, Yb, and Lu, R' is constituted by at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Dy, Gd, Eu, Tb, Tm, Yb, and Lu, x is a number of from 0 to 0.1 and e is a number of from 0 to 0.2. .Iaddend. .Iadd. 8. A birefringent device comprising: 
       a crystal element made of molybdate gadolinium oxide crystal structure given by the formula   R.sub.2 O.sub.3.3 Mo.sub.1.sub.-e W.sub.e O.sub.3,     
       where e is a number of from 0 to 0.2, and R is an element selected from the group of Sm, Tb, Dy and Eu; and 
       means, connected to said crystal, for placing said crystal in one of the reversibly birefringent states thereof. .Iaddend..Iadd. 9. A device according to claim 8, wherein said means for placing said crystal in one of the reversibly birefringent states thereof comprises means for imparting a mechanical stress to the crystal at least equal to the coercive stress thereof. .Iaddend. .Iadd. 10. A device according to claim 8, wherein said means for placing said crystal in one of the reversible birefringent states thereof comprises means for applying an electric field across said crystal at least equal to the coercive field of said crystal. .Iaddend..Iadd. 11. A device according to claim 10, wherein said means for applying an electric field comprises a voltage source and a pair of electrodes connected to said crystal for receiving the voltage from said voltage source and applying said electric field across said crystal. .Iaddend..Iadd. 12. A device according to claim 10, wherein said means for placing said crystal in one of the reversibly birefringent states thereof comprises means for applying a voltage pulse to said crystal. .Iaddend..Iadd. 13. A birefringent device comprising: 
       a crystal element made of molybdate gadolinium oxide crystal structure given by the formula   (R.sub.x R'.sub.1.sub.-x).sub.2 O.sub.3.3Mo.sub.1.sub.-3 W.sub.e O.sub.3     
       where R is constituted by at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Dy, Eu, Tb, Tm, Yb, and Lu, R' is constituted by at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Dy, Gd, Eu, Tb, Tm, Yb, and Lu, x is a number of from 0 to 0.1 and e is a number of from 0 to 0.2; and 
       means connected to said crystal, for placing said crystal in one of the reversibly birefringent states thereof. .Iaddend..Iadd. 14. A device according to claim 13, wherein said means for placing said crystal in one of the reversibly birefringent states thereof comprises means for imparting a mechanical stress to the crystal at least equal to the coercive stress thereof. .Iaddend..Iadd. 15. A device according to claim 13, wherein said means for placing said crystal in one of the reversible birefringent states thereof comprises means for applying an electric field across said crystal at least equal to the coercive electric field of said crystal. .Iaddend..Iadd. 16. A device according to claim 15, wherein said means for applying an electric field comprises a voltage source and a pair of electrodes connected to said crystal for receiving the voltage from said voltage source and applying said electric field across said crystal. .Iaddend..Iadd. 17. A device according to claim 15, wherein said means for placing said crystal in one of the reversibly birefringent states thereof comprises means for applying a voltage pulse to said crystal. .Iaddend.