Potential of Bi-substituted sputtered garnet media for high density recording using shorter wavelength lasers

Dynamic recording using Bi-substituted sputtered garnet media on a GGG (Gd₃Ga₅O₁₂) substrate was performed using several wavelengths of an Ar ion laser. Good writing sensitivity and high carrier-to-noise ratios (CNRs) were obtained in the blue region of the spectrum, indicating that a SHG (second harmonic generation) laser could be adopted as the light source for ultrahigh-density recording. A 785-nm laser-diode tracking servo was reliably performed for pregrooved substrates, producing a CNR of 48 dB. Overwrite experiments using magnetic field modulation were also performed. A CNR of 48 dB was obtained and complete erasure was confirmed