The first papers on holographic storage were published in 1963 Holographic storage is using the entire medium instead of a few layers.You use 2 laser beams instead of one with one carrying the data and the other being a reference beam.
So how do they actually get data onto a holographic disk.Data is converted into binary code just like we do today.Computer binary code is converted into optical patterns of dark and light pixels to represent the 1’s and 0’s.
Spatial light modulators (SLM) are pixelated input devices (liquid crystal panels), used to imprint the data to be stored on the object beam. LargeSpatial Light Modulator’s (SLMs) are placed on overhead projectors to project computer monitor contents to the screen like what is being used today to convey this presentation onto the wall.
Animation showing the information beam and the data beam of the Holographic laser. Where the two beams intersect is where the data is written.By adjusting the reference beam angle, wavelength (color), or media position, a multitude of holograms (theoretically, several thousand) can be stored on a single volume.
Illustration of what the holographic image looks like as it is being written onto the recording layer.
A dichroic mirror layer between the holographic data and the servo data reflects the green laser while letting the red laser pass through. This prevents interference from refraction of the green laser off the servo data pits and is an advance over past holographic storage media, which either experienced too much interference, or lacked the servo data entirely, making them incompatible with current CD and DVD drive technology.The servo beam in the HVD system is at a wavelength that does not photosensitize the polymer recording medium but is used to help track and focus the data. The structure of the disc places a thick recording layer between two substrates and incorporates a dichroic mirror that reflects the blue or green light carrying the reference patternbut allows the red light to pass through in order to gather servo information.
The HVD (Holographic Versatile Disc) format is currently promoted by the HVD Alliance who was formed to discuss the standards for this medium. Optware is also working to standardize the HVD format through the Ecma International industry association (www.ecma-international.org), which develops standards for Information and Communication Technology (ICT) and Consumer Electronics (CE).
Animation showing the writing process.
Animation showing the reading process.
There are several reasons for the interest in holographic data storage. The biggest and utmost being the demand for more storage from various industries now that everything is digitized.
Dentists are using digital x-rays of teethOptometrists are using digital retinal scansDoctors and the medical field in general are going digital in all their scans.Data Warehousing.Any field that uses large amounts of data which needs to be archived.So the demand for storage space to archive all this additional information is increasing.
Capacity comparison between DVD’s and HVD’s.
The Voyager Golden Records are phonograph records which were included aboard both Voyager spacecraft, which were launched in 1977. They contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for future humans, who may find them. It contained 116 images and a variety of natural sounds, such as those made by surf, wind, and thunder, and animal sounds, including the songs of birds and whales. To this they added musical selections from different cultures and eras, spoken greetings in fifty-five languages. Just think what they could put on a holographic disk (like a dictionary).
Holographic storage records and reads out data in a massively parallel manner, unlike the serial “one bit at a time” approach of traditional technologies. Digital data is stored and recovered as million-bit blocks rather than as single bits, enabling ultrafast data-transfer rates. This means a photograph can be saved in it’s entirety in one flash of light.You are literally recording data at the speed of light.
One bit at a time vs. entire page (60,000 bits) at a time.Flashes of light compared to actually burning the medium.
Archival Life expectancy is an estimated figure do to the environmental conditions that can affect a disk along with the quality and care in storing the disk. Virtually all CD-Rs tested indicated an estimated life expectancy beyond 15 years. Only 47 percent of the recordable DVDs tested indicated an estimated life expectancy beyond 15 years. Some had a predicted life expectancy as short as 1.9 years. Exposure to humidity, temperature, sunlight, mishandling, etc. along with the quality of the recording medium will affect the life expectancy.Counterpoints to this claim are that the evolution of data reader technology changes every ten years; therefore, being able to store data for 50–100 years would not matter if you could not read or access it.
For mass production, holographic media can be replicated very efficiently in one simultaneous transfer from a master. But once written, the replicated discs cannot be used as masters for further copying.By adjusting one of its laser beams, Collinear technology can provide a physical level of on-disk encryption during recording and reading, which holds great promise for digital rights management and other applications requiring high levels of security.
Almost the entire HDSS device can now be made from off-the-shelf components, which means that it could be mass-produced.However, up till now, there was no adequate recording medium to use – kind of like being all dressed up with no place to go.
A digital micro-mirror device, or DMD, is an optical semiconductor that is the core of DLP (Digital Light Processing) projection technology used in some TVs and video projectors.
CMOS (complimentary metal-oxide semiconductor) convert light into electrons.CMOS traditionally consumes little power.CMOS chips can be fabricated on just about any standard silicon production line, so they tend to be extremely inexpensive.
Key partners that have supplied the parts needed to build a holographic data storage unit.Founding members include CMC Magnetics (manufacturer of optical storage media), Fuji Photo Film (imaging media), Nippon Paint (paints and coating industry), Pulstec (test equipment), Toagosei (chemicals, photoresists, acrylic plastics, etc.) and Optware (research). Toshiba, Matsushita and Konica Minolta have also supported the HVD format.
Various on-line sources were used to create this presentation.
Expected (hoped) to hit the market by 2019.
Holographic memory system
What is HolographyHolography is a technique which enables three-dimensional images to be made. It involves theuse of a laser, interference, diffraction,light intensity recording and suitable illuminationof the recording.The image changes as the position andorientation of the viewing system changes inexactly the same way as if the object were stillpresent, thus making the image appear three-dimensional.
Who invented holography?Dennis Gabor wasa Hungarian-British electricalengineer and physicist, mostnotable forinventing holography, for whichhe later received the1971 Nobel Prize in Physics
Three dimensional or “holographic” datastorage involves using the entire mediafor storage, not just a few layers like wecurrently use today.The process is accomplished by usingtwo laser beams, instead of one, towrite data to the disk.
1. The object is converted into binarycode of 1’s and 0’s like we use today.2. Next, the 1’s and 0’s are convertedinto a matrix of light and dark squares.
3. Those light and dark squares are thenelectronically sent to a spatial lightmodulator (SLM).4. The laser beam then shines throughthe spatial light modulator (SLM).5. Pixels of the spatial light modulatorfilter (block or allow) the light thusencoding the data into the laser beam.
A green and red laser beamare collimated in a single beam.The green laser reads data encodedas laser interference fringes froma holographic layer near the top ofthe disc.A red laser is used as the referencebeam to read servoinformation froma regular CD-style aluminium layernear the bottom.Red - 650 nmGreen – 532 nm
Many disk prototypeshave been looked at overthe years, however, theindustry standard hasnow accepted havingthe HVD disk include areflective layer in order tobe backward compatibleand to assist withtracking of the writebeam. Di-isobutylacrylamide(DBA)
A simplified HVD systemconsists of the following maincomponents:•Blue or green laser (532-nmwavelength in the test system)•Beam splitter/merger•Mirrors•Spatial light modulator (SLM)•CMOS sensor•Photopolymer recording medium
In today’s world, digital media is becomingmore and more common and is requiringmore storage to meet the new demands.More industries are now using digitalstorage than ever before.200 DVD’s can fit on one 1 TB holographicdisk with a future capacity of 6 terabytes.
IBMs test platforms can store up to 390bits per square micron (a micron is amillionth of a metre). DVDs, by contrast,have a storage density of about five bitsper square micron.DVD DVD Blu-Ray Blu-Ray HVDNumber of Layers Single Dual Single Dual 200+/-Recording Capacity 4.7GB 9.4GB 25GB 50GB 1TBData Transfer Rate 11.08Mb/s 11.08Mb/s 36Mb/s 36Mb/s 1GB/s
It has been estimated that all the books in theU.S. Library of Congress, could be stored on six(6) HVDs.The pictures of every landmass on Earth(Google Earth for example) can be stored ontwo (2) HVDs.With MPEG4 ASP encoding, a HVD can holdbetween 4,600 to 11,900 hours of video, whichis enough for non-stop playing for a year.
Holography allows a million bits ofdata to be written and read out insingle flashes of light, enabling datatransfer rates as high as a billion bitsper second (fast enough to transfer aDVD movie in about 30 seconds).
HVD’s have an estimated archival lifeexpectancy of at least 50 years or morecompared to CD/DVD archival life of 2 to5 years (even though published lifeexpectancies are often cited as 10 to 25years or longer for optical media, itdepends on the storage conditions andquality of the disks).
HVD storage also offers interesting possibilities for dataprotection. For mass production, holographic media canbe replicated very efficiently in one simultaneoustransfer from a master. But once written, the replicateddiscs cannot be used as masters for further copying.By adjusting one of its laser beams, Collineartechnology can provide a physical level of on-diskencryption during recording and reading, which holdsgreat promise for digital rights management and otherapplications requiring high levels of security.
Low cost materials needed to comeavailable which are just now happeningdue to other industries utilizing newtechnology.Development of needed components,in fields outside the storage industry,have brought the cost down making itfinancially viable to proceed.
Green lasers now used in the medical,cable TV, and printing industries areattractive recording sources due to theirsmall size, ruggedness and low cost.Digital micro-mirror devices appearing innew types of displays are ideal spatiallight modulators (SLM). This overheadprojector for instance uses a SLM.
The CMOS active pixel detector arraysemerging in digital photography exhibit therapid access and data transfer propertiesrequired for holography. CMOS sensorswere originally proposed for the detectionof visible light in cameras. In theholography field, they can detect the lightpatterns that are stored on the disks.
The Economist, Holographic data storage, Jul 31, 2003,http://www.economist.com/node/1956881 General Electric Global Research InPhase Technologies, Longmont, Colorado,http://www.inphase-technologies.com/ Wikipedia – Holographic Data Storage,http://en.wikipedia.org/wiki/Holographic_data_storage Bell Laboratories Physical Sciences Research, http://www.bell-labs.com/org/physicalsciences/projects/hdhds/1.html How Holographic Memory Will Work by Kevin Bosner.http://computer.howstuffworks.com/holographic-memory1.htm Optware Corporation of America, Longmont, Colorado,http://www.thic.org/pdf/Jul05/optware.mdeese.050719.pdf Technology Review, July 2010,http://www.technologyreview.com/blog/mimssbits/25418/
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