Optical information recording medium and its recording and reproducing method

A method for recording and reproducing information with light beams and an optical information recording medium, the optical information recording medium comprising a substrate having a groove for guiding light beams and a recording layer in which a reflectance changes by irradiation with said light beams;

• wherein the reflectance of the light beams after recording is greater than the reflectance of the light beams before recording;
• the depth of said groove for guiding light beams is in the range of λ/8n to 3λ/8n, where λ is a wavelength of said light beams and n is a refractive index of said substrate;
• the reflectance after recording is greater than the reflectance before recording;
• the method comprising selecting a phase difference, Δφ=φ1−φ0, between the phase φ1 of the reflected light after recording and the phase φ0 of the reflected light before recording that is sufficient to inhibit crosstalk and that is between (−0.1+2 m)π and (0.1+2 m)π, where m is an integer having an absolute value that is greater or equal to one.

A method for recording and reproducing information with light beams and an optical information recording medium, the optical information recording medium comprising a substrate having a groove for guiding light beams and a recording layer in which a reflectance changes by irradiation with said light beams;

• wherein the reflectance of the light beams after recording is greater than the reflectance of the light beams before recording;
• the depth of said groove for guiding light beams is in the range of λ/8n to 3λ/8n, where λ is a wavelength of said light beams and n is a refractive index of said substrate;
• the reflectance after recording is greater than the reflectance before recording;
• the method comprising selecting a phase difference, Δφ=φ1−φ0, between the phase φ1 of the reflected light after recording and the phase φ0 of the reflected light before recording that is sufficient to inhibit crosstalk and that is equal to zero.