HOLOGRAPHIC DIGITAL DATA STORAGE SYSTEM CAPABLE OF ENHANCING RECORDING DENSITY

摘要

PURPOSE: A holographic digital data storage system is provided to reduce the size of a reference light and change an incidence position and a deflection angle of the reference light, thereby increasing the recording density. CONSTITUTION: A light source(200) generates laser light. A light splitter(204) splits the laser light into reference light for recording and signal light. A space light modulator(218) modulates the signal light into one page unit of binary data formed by light and darkness made of pixels according to data inputted from the outside. A light reduction unit(206) comprises a transmission region for transmitting a portion of the reference light and a non-transmission region for reflecting or absorbing other portion of the reference light. A first actuator(208) moves the transmission region of the light reduction unit toward left and right and changes the position of the transmission region. A first reflection mirror(210) deflects the incidence reduced reference light through the transmission region of the light reduction unit with a predetermined angle. A second reflection mirror(212) transmits the incidence reduced reference light from the first reflection mirror as parallel beam with a deflection angle. A first lens transmits the reference light deflected by the second reflection mirror to a storage medium. A second actuator(214) changes the position of the second reflection mirror and the incidence position of the reduced reference light toward the first lens, thereby controlling the reduced deflection angle. The storage medium moves continuously linearly in order to store the digital data. Interference pattern formed by the incidence reference light through the first lens and the incidence modulated signal light from the space light modulator is stored to the storage medium.