A. Toriumi et al., NONDESTRUCTIVE READOUT OF A 3-DIMENSIONAL PHOTOCHROMIC OPTICAL MEMORYWITH A NEAR-INFRARED DIFFERENTIAL PHASE-CONTRAST MICROSCOPE, Optics letters, 22(8), 1997, pp. 555-557
A three-dimensional (3D) rewritable optical memory using photochromic
material is described for high-density memory. The bits are recorded i
n a 3D volume of photochromic material. A transformation of the photoc
hromic molecule between two isomers with different absorption spectra
can be stimulated by irradiation with appropriate wavelengths. We show
that a nondestructive readout of photochromic memory is possible by u
se of a small difference in the refractive index of the photochromic i
somers in the near-IR range. For this purpose a near-IR laser-scan dif
ferential phase-contrast microscope is used. Experimental results of 3
D recording and nondestructive reading are presented. (C) 1997 Optical
Society of America.