3D Holographic Storage
Holography is a method of recording an object's image in such a way that when viewed later appears three dimensional. A light field is created by a laser source that illuminates both the object and the recording media. The scattered light from the object interferes with the reference light and it is this interference pattern that creates the image. Light from a laser is split in two and, via optical components, is formed to illuminate the object and the recording media.
Holograms are used in many different areas such as artistic displays, security marking and data storage. This latter application is particularly interesting as it offers the possibility of storing far higher quantities of data compared to magnetic or 2D optical methods, with the added benefit of the data being read at far higher rates.
In order for the interference pattern to be encoded with information about the object, the coherence length of the illuminating light is an important factor and due to the long exposure times needed, the available power, wavelength stability and divergence of the beam are critical.
The coherence length of the laser becomes less critical when being used to copy/print a hologram and many of our lasers are suitable, however the torus range from Laser Quantum are ideal for all holography applications as the beams have long (>100 m) coherence lengths, divergence and the mode stability that only active locking provides.
Holograms are used in many different areas such as artistic displays, security marking and data storage. This latter application is particularly interesting as it offers the possibility of storing far higher quantities of data compared to magnetic or 2D optical methods, with the added benefit of the data being read at far higher rates.
In order for the interference pattern to be encoded with information about the object, the coherence length of the illuminating light is an important factor and due to the long exposure times needed, the available power, wavelength stability and divergence of the beam are critical.
The coherence length of the laser becomes less critical when being used to copy/print a hologram and many of our lasers are suitable, however the torus range from Laser Quantum are ideal for all holography applications as the beams have long (>100 m) coherence lengths, divergence and the mode stability that only active locking provides.
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torus 532nm - Green Single Longitudinal Mode (SLM) laser with active mode locking. The torus 532 laser is a high specification, green single frequency laser. Using intelligent electronics, the torus continually tracks its longitudinal mode position and ensures there is no mode-hop. The torus is available at 532 nm, with powers ranging from 50 mW - 750 mW making it ideal for applications such as holography, Brillouin scattering and Raman spectroscopy. The torus is a single longitudinal mode laser. Control of the laser can be accessed through a dedicated RS232 port on the PSU. The unique patented travelling-wave cavity results in an ultra-low noise output. torus 660nm – Red SLM laser with active mode locking
The torus 660 nm laser provides true single longitudinal mode (SLM) with a coherence length in excess of 100 m and a bandwidth of <1 MHz. Using TruLoQ™ active mode locking technology to stabilise the laser cavity, the wavelength stability is measured to be <2 pm over 20°C ambient temperature shift and mode hop is eliminated. The torus 660 is ideal for applications such as interferometry, Raman studies and holography. |
