Lasers for Holography

The basic principles of holography were discovered in the first half of the 20th century by Nobel Prize winner Dennis Gabor who was awarded the prize 1971 for his ‘invention and development of the holographic method’ [1]. But it was only after the laser was invented in 1960 when optical holography as a recording method and as a technique to display 3D images as an art form took off.

Todays increased availability of more compact and powerful single longitudinal mode (SLM) solid-state lasers with the long coherence length and stable wavelength required to write holograms, along with the development of a new generation of sensitive emulsions and the availability of wavelength selectable LED based illumination sources have opened up new application areas for holographic techniques.

Today’s holographic applications include making security holograms on bank notes or passports, generation of ultra-realistic full-color 3D replicas of objects and production of so-called holographic optical elements (HOE’s) used, for instance, for image projection in virtual reality (VR) and augmented reality (AR) devices.

In many applications, e.g in the security industry, high volume replication of HOEs is typically achieved with embossing techniques. However, for AR/VR glasses the requirements on resolution are much higher and therefore lasers are needed for printing these HOEs.