A holographic recording and/or retrieval method and apparatus are provided. An
optical recording medium is used which has a recording layer, formed on a surface
of a transparent substrate, through which light having an incident angle of a predetermined
value or more with respect to the surface is guided, and which changes a refractive
index or absorption coefficient upon simultaneous irradiation of signal light of
a predetermined wavelength and reference light, and can record holograms by holding
the changed refractive index or absorption coefficient. During recording, a hologram
is recorded by simultaneously irradiating the recording layer with signal light
of predetermined wavelength and reference light. During retrieval, reading light
of wavelength that does not change a refractive index or absorption coefficient
of the recording layer is guided through the recording layer, and a hologram is
retrieved by diffracted light produced when the reading light is guided through
the recording layer.
