Holographic printer

A holographic printer for directly writing 1-step white-light viewable holograms, comprising:

• a pulsed laser source arranged to produce a laser beam at a first wavelength, said laser beam being split into an object beam and a reference beam which is mutually coherent with said object beam;
• a spatial light modulator wherein, in use, said object beam illuminates said spatial light modulator;
• a lens system for writing a holographic pixel of a hologram on to a photosensitive medium, said lens system being arranged downstream of said spatial light modulator;
• and
• positioning means for positioning a photosensitive medium at the Fourier plane of said lens system;
• wherein said holographic printer further comprises a second and a third laser source for producing laser beams at second and third wavelengths, and wherein said first, second and third wavelengths each differ from one another by at least 30 nm.

A method of directly writing 1-step white-light viewable holograms, comprising:

• providing a pulsed laser source arranged to produce a laser beam at a first wavelength;
• splitting said laser beam into an object beam and a reference beam which is mutually coherent with said object beam;
• illuminating a spatial light modulator with said object beam;
• providing a lens system for writing a holographic pixel of a hologram on to a photosensitive medium, said lens system being arranged downstream of said spatial light modulator;
• and
• positioning a photosensitive medium at the Fourier plane of said lens system;
• wherein said laser source is arranged to additionally produce laser beams at second and third wavelengths, and wherein said first, second and third wavelengths each differ from one another by at least 30 nm.

A method of directly writing 1-step white-light viewable holograms, comprising:

• providing a pulsed laser source arranged to produce a laser beam at a first wavelength;
• splitting said laser beam into an object beam and a reference beam which is mutually coherent with said object beam;
• illuminating a spatial light modulator with said object beam;
• providing a lens system for writing a holographic pixel of a hologram on to a photosensitive medium, said lens system being arranged downstream of said spatial light modulator;
• and
• positioning a photosensitive medium at the Fourier plane of said lens system;
• wherein said holographic printer further comprises a second and a third laser source for producing laser beams at second and third wavelengths, and wherein said first, second and third wavelengths each differ from one another by at least 30 nm.