Holographic writing method and holographic writing apparatus

A holographic writing apparatus for writing holographic information by emitting a beam at a holographic recording medium containing a photo-responsable polymer material having photoisomerization characteristics that change a molecular structure thereof by absorbing light energy, the holographic writing apparatus comprises a light emission unit configured to write the holographic information by emitting the beam at the holographic recording medium, the light emission unit writing the holographic information by emitting the beam at a writing wavelength different from a maximum absorption wavelength in a light absorption spectrum of photoisomer molecule structures of the holographic recording medium,

• wherein the maximum absorption wavelength is a wavelength at which light absorption rate is maximum in the light absorption spectrum, and a difference between the light absorption rates of the photoisomer molecule structures at the writing wavelength is less than a difference between the light absorption rates of the photoisomer molecule structures at the maximum absorption wavelength,
• wherein the photoisomer molecule structures include a trans-isomer molecule structure and a cis-isomer molecule structure, and
• wherein the writing wavelength is in a range of 5 nm to 15 nm greater than the wavelength at which light absorption rates of the trans-isomer molecule structure and the cis-isomer molecule structure of the photoisomer molecule structures match in the light absorption spectrum.