Wavelength control method controlling waveform for recording or reproducing information with holography, hologram information processing apparatus and hologram recording medium

摘要

For controlling a wavelength of laser light of a wavelength-variable laser (step S0), an optical system or a hologram recording medium is moved (step S1) to attain a state in which a light beam enters a wavelength control pattern. Reference light that is the laser light is applied to the wavelength control pattern (step S2). Then, a light receiving element observes reproduction light from the wavelength control pattern (step S3). A wavelength of the reference light that is the laser light is minutely changed. A quantity of the reproduction light changes with the wavelength. The quantity of the reproduction light is monitored to obtain a specific wavelength λ₀ (a rotation angle of a diffraction grating 52) maximizing the quantity of the reproduction light (step S4). The wavelength of the laser light of the wavelength-variable laser light source is adjusted (step S5).