Recording medium and recording system

A recording system for recording data three-dimensionally on a recording medium by the irradiation of a recording laser beam, the recording system comprising:

• a retention device for movably retaining the recording medium, the recording medium comprising a reflection control layer comprising a plurality of reflection layers stacked in a film thickness direction, each reflection layer having a connection terminal, each reflection layer exhibiting reflectivity and transmissivity changeable in response to an electrical signal supplied to the connection terminal and a recording layer disposed at a beam incidence side of the reflection control layer, wherein the recording layer has a film thickness greater than a distance between a focal position when the recording laser beam is reflected by the farthest reflection layer from the recording layer of the reflection layers and a focal position when the recording laser beam is reflected by the nearest reflection layer to the recording layer of the reflection layers;
• an optical device comprising an object lens for retaining the recording laser beam, such that the recording laser beam is transmitted through the recording layer and the reflection layers from a recording layer side and is then condensed, in a state in which a beam is transmitted through all the reflection layers;
• and a selection device electrically connected to the connection terminals of the recording medium for alternatively selecting the reflection layers to condense the recording laser beam at positions in the recording layer different in the film thickness direction.