Information recording medium and method for producing the same, recording or reproducing method, and optical information recording and reproducing device

A recording or reproducing method for recording or reproducing information to or from an information recording medium comprising a recording portion upon which information can be recorded by irradiating the information recording medium with a recording light or a reproducing light, the recording portion including:

• a first phosphor that has a property of absorbing a first light having a wavelength of λ1/n and then emitting a second light, where λ1 is a wavelength of the recording light and n is an integer not less than 2;
• and a photon-mode photosensitive material that absorbs the second light and then exhibits a change in an optical constant thereof, a n-photon absorption sensitivity of the first phosphor with respect to the recording light is greater than a n-photon absorption sensitivity of the photosensitive material with respect to the recording light, the method comprising the step of:
• irradiating the recording portion with the recording light so that the second light emitted from the first phosphor causes the optical constant of the photosensitive material to change.

36-46. (canceled)