<s>
Holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
is	O
a	O
potential	O
technology	O
in	O
the	O
area	O
of	O
high-capacity	O
data	B-General_Concept
storage	I-General_Concept
.	O
</s>
<s>
While	O
magnetic	O
and	O
optical	B-General_Concept
data	I-General_Concept
storage	I-General_Concept
devices	O
rely	O
on	O
individual	O
bits	O
being	O
stored	O
as	O
distinct	O
magnetic	O
or	O
optical	O
changes	O
on	O
the	O
surface	O
of	O
the	O
recording	O
medium	O
,	O
holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
records	O
information	O
throughout	O
the	O
volume	O
of	O
the	O
medium	O
and	O
is	O
capable	O
of	O
recording	O
multiple	O
images	O
in	O
the	O
same	O
area	O
utilizing	O
light	O
at	O
different	O
angles	O
.	O
</s>
<s>
Additionally	O
,	O
whereas	O
magnetic	O
and	O
optical	B-General_Concept
data	I-General_Concept
storage	I-General_Concept
records	O
information	O
a	O
bit	O
at	O
a	O
time	O
in	O
a	O
linear	O
fashion	O
,	O
holographic	B-Algorithm
storage	I-Algorithm
is	O
capable	O
of	O
recording	O
and	O
reading	O
millions	O
of	O
bits	O
in	O
parallel	O
,	O
enabling	O
data	O
transfer	O
rates	O
greater	O
than	O
those	O
attained	O
by	O
traditional	O
optical	B-General_Concept
storage	I-General_Concept
.	O
</s>
<s>
Holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
contains	O
information	O
using	O
an	O
optical	O
interference	O
pattern	O
within	O
a	O
thick	O
,	O
photosensitive	O
optical	O
material	O
.	O
</s>
<s>
By	O
adjusting	O
the	O
reference	B-Algorithm
beam	I-Algorithm
angle	O
,	O
wavelength	O
,	O
or	O
media	O
position	O
,	O
a	O
multitude	O
of	O
holograms	B-Algorithm
(	O
theoretically	O
,	O
several	O
thousands	O
)	O
can	O
be	O
stored	O
on	O
a	O
single	O
volume	O
.	O
</s>
<s>
The	O
stored	B-General_Concept
data	I-General_Concept
is	O
read	O
through	O
the	O
reproduction	O
of	O
the	O
same	O
reference	B-Algorithm
beam	I-Algorithm
used	O
to	O
create	O
the	O
hologram	B-Algorithm
.	O
</s>
<s>
The	O
reference	B-Algorithm
beam	I-Algorithm
's	O
light	O
is	O
focused	O
on	O
the	O
photosensitive	O
material	O
,	O
illuminating	O
the	O
appropriate	O
interference	O
pattern	O
,	O
the	O
light	O
diffracts	O
on	O
the	O
interference	O
pattern	O
,	O
and	O
projects	O
the	O
pattern	O
onto	O
a	O
detector	O
.	O
</s>
<s>
Files	O
on	O
the	O
holographic	B-Algorithm
drive	O
can	O
be	O
accessed	O
in	O
less	O
than	O
0.2	O
seconds	O
.	O
</s>
<s>
Holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
can	O
provide	O
companies	O
a	O
method	O
to	O
preserve	O
and	O
archive	O
information	O
.	O
</s>
<s>
The	O
write-once	O
,	O
read	O
many	O
(	O
WORM	B-Device
)	O
approach	O
to	O
data	B-General_Concept
storage	I-General_Concept
would	O
ensure	O
content	O
security	O
,	O
preventing	O
the	O
information	O
from	O
being	O
overwritten	O
or	O
modified	O
.	O
</s>
<s>
Manufacturers	O
believe	O
this	O
technology	O
can	O
provide	O
safe	O
storage	O
for	O
content	O
without	O
degradation	O
for	O
more	O
than	O
50	O
years	O
,	O
far	O
exceeding	O
current	O
data	B-General_Concept
storage	I-General_Concept
options	O
.	O
</s>
<s>
However	O
,	O
claimed	O
longevity	O
of	O
storage	O
has	O
,	O
in	O
the	O
past	O
,	O
proven	O
to	O
be	O
a	O
key	O
indicator	O
of	O
shorter-term	O
reliability	O
of	O
storage	B-General_Concept
media	I-General_Concept
.	O
</s>
<s>
Current	O
optical	O
formats	O
–	O
such	O
as	O
CD	B-Device
–	O
have	O
largely	O
lived	O
up	O
to	O
the	O
original	O
longevity	O
claims	O
(	O
where	O
reputable	O
media	O
makes	O
are	O
used	O
)	O
and	O
have	O
proved	O
to	O
be	O
more	O
reliable	O
shorter-term	O
data	O
carriers	O
than	O
the	O
floppy	B-Device
disk	I-Device
and	O
DAT	O
media	O
they	O
displaced	O
.	O
</s>
<s>
Sensitivity	O
refers	O
to	O
the	O
extent	O
of	O
refractive	O
index	O
modulation	B-Application
produced	O
per	O
unit	O
of	O
exposure	O
.	O
</s>
<s>
Diffraction	O
efficiency	O
is	O
proportional	O
to	O
the	O
square	O
of	O
the	O
index	O
modulation	B-Application
times	O
the	O
effective	O
thickness	O
.	O
</s>
<s>
The	O
dynamic	O
range	O
determines	O
how	O
many	O
holograms	B-Algorithm
may	O
be	O
multiplexed	B-Architecture
in	O
a	O
single	O
volume	O
data	O
.	O
</s>
<s>
Spatial	O
light	O
modulators	B-Application
(	O
SLM	O
)	O
are	O
pixelated	O
input	O
devices	O
(	O
liquid	O
crystal	O
panels	O
)	O
,	O
used	O
to	O
imprint	O
the	O
data	O
to	O
be	O
stored	O
on	O
the	O
object	O
beam	O
.	O
</s>
<s>
Like	O
other	O
media	O
,	O
holographic	B-Algorithm
media	O
is	O
divided	O
into	O
write	O
once	O
(	O
where	O
the	O
storage	B-General_Concept
medium	I-General_Concept
undergoes	O
some	O
irreversible	O
change	O
)	O
,	O
and	O
rewritable	O
media	O
(	O
where	O
the	O
change	O
is	O
reversible	O
)	O
.	O
</s>
<s>
Rewritable	O
holographic	B-Algorithm
storage	I-Algorithm
can	O
be	O
achieved	O
via	O
the	O
photorefractive	O
effect	O
in	O
crystals	O
:	O
</s>
<s>
These	O
two	O
sources	O
are	O
called	O
the	O
reference	B-Algorithm
beam	I-Algorithm
and	O
the	O
signal	O
beam	O
.	O
</s>
<s>
The	O
positively	O
charged	O
vacancies	O
they	O
leave	O
are	O
called	O
holes	O
and	O
they	O
must	O
be	O
immobile	O
in	O
rewritable	O
holographic	B-Algorithm
materials	O
.	O
</s>
<s>
This	O
rate	O
will	O
affect	O
the	O
strength	O
of	O
the	O
hologram	B-Algorithm
.	O
</s>
<s>
When	O
the	O
information	O
is	O
to	O
be	O
retrieved	O
or	O
read	O
out	O
from	O
the	O
hologram	B-Algorithm
,	O
only	O
the	O
reference	B-Algorithm
beam	I-Algorithm
is	O
necessary	O
.	O
</s>
<s>
The	O
beam	O
is	O
sent	O
into	O
the	O
material	O
in	O
exactly	O
the	O
same	O
way	O
as	O
when	O
the	O
hologram	B-Algorithm
was	O
written	O
.	O
</s>
<s>
Something	O
like	O
a	O
CCD	B-Algorithm
camera	I-Algorithm
can	O
be	O
used	O
to	O
convert	O
this	O
information	O
into	O
a	O
more	O
usable	O
form	O
.	O
</s>
<s>
Holograms	B-Algorithm
can	O
theoretically	O
store	O
one	O
bit	O
per	O
cubic	O
block	O
the	O
size	O
of	O
the	O
wavelength	O
of	O
light	O
in	O
writing	O
.	O
</s>
<s>
Using	O
light	O
of	O
this	O
wavelength	O
,	O
perfect	O
holographic	B-Algorithm
storage	I-Algorithm
could	O
store	O
500	O
megabytes	O
per	O
cubic	O
millimeter	O
.	O
</s>
<s>
Unlike	O
current	O
storage	O
technologies	O
that	O
record	O
and	O
read	O
one	O
data	O
bit	O
at	O
a	O
time	O
,	O
holographic	B-Algorithm
memory	I-Algorithm
writes	O
and	O
reads	O
data	O
in	O
parallel	O
in	O
a	O
single	O
flash	O
of	O
light	O
.	O
</s>
<s>
For	O
two-color	O
holographic	B-Algorithm
recording	O
,	O
the	O
reference	O
and	O
signal	O
beam	O
fixed	O
to	O
a	O
particular	O
wavelength	O
(	O
green	O
,	O
red	O
or	O
IR	O
)	O
and	O
the	O
sensitizing/gating	O
beam	O
is	O
a	O
separate	O
,	O
shorter	O
wavelength	O
(	O
blue	O
or	O
UV	O
)	O
.	O
</s>
<s>
Readout	O
is	O
achieved	O
by	O
illumination	O
with	O
the	O
reference	B-Algorithm
beam	I-Algorithm
alone	O
.	O
</s>
<s>
Usually	O
,	O
for	O
two-color	O
holographic	B-Algorithm
recording	O
,	O
two	O
different	O
dopants	O
are	O
required	O
to	O
promote	O
trap	O
centers	O
,	O
which	O
belong	O
to	O
transition	O
metal	O
and	O
rare-earth	O
elements	O
and	O
are	O
sensitive	O
to	O
certain	O
wavelengths	O
.	O
</s>
<s>
Reading	O
would	O
be	O
done	O
with	O
the	O
reference	B-Algorithm
beam	I-Algorithm
since	O
the	O
electrons	O
can	O
no	O
longer	O
be	O
excited	O
out	O
of	O
the	O
deep	O
traps	O
by	O
the	O
long	O
wavelength	O
beam	O
.	O
</s>
<s>
For	O
a	O
doubly	O
doped	O
lithium	O
niobate	O
(	O
LiNbO3	O
)	O
crystal	O
there	O
exists	O
an	O
optimum	O
oxidation/reduction	B-Operating_System
state	O
for	O
desired	O
performance	O
.	O
</s>
<s>
In	O
a	O
strongly	O
oxidized	O
sample	O
holograms	B-Algorithm
cannot	O
be	O
easily	O
recorded	O
and	O
the	O
diffraction	O
efficiency	O
is	O
very	O
low	O
.	O
</s>
<s>
However	O
,	O
during	O
readout	O
,	O
all	O
the	O
deep	O
traps	O
get	O
filled	O
quickly	O
and	O
the	O
resulting	O
holograms	B-Algorithm
reside	O
in	O
the	O
shallow	O
traps	O
where	O
they	O
are	O
totally	O
erased	O
by	O
further	O
readout	O
.	O
</s>
<s>
Hence	O
after	O
extensive	O
readout	O
the	O
diffraction	O
efficiency	O
drops	O
to	O
zero	O
and	O
the	O
hologram	B-Algorithm
stored	O
cannot	O
be	O
fixed	O
.	O
</s>
<s>
Developed	O
from	O
the	O
pioneering	O
work	O
on	O
holography	B-Algorithm
in	O
photorefractive	O
media	O
and	O
holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
of	O
Gerard	O
A	O
.	O
Alphonse	O
,	O
InPhase	B-Algorithm
conducted	O
public	O
demonstrations	O
of	O
the	O
a	O
prototype	O
commercial	O
storage	O
device	O
,	O
at	O
the	O
National	O
Association	O
of	O
Broadcasters	O
2005	O
(	O
NAB	O
)	O
convention	O
in	O
Las	O
Vegas	O
,	O
at	O
the	O
Maxell	O
Corporation	O
of	O
America	O
booth	O
.	O
</s>
<s>
The	O
three	O
main	O
companies	O
involved	O
in	O
developing	O
holographic	B-Algorithm
memory	I-Algorithm
,	O
as	O
of	O
2002	O
,	O
were	O
InPhase	B-Algorithm
and	O
Polaroid	O
spinoff	O
Aprilis	O
in	O
the	O
United	O
States	O
,	O
and	O
Optware	O
in	O
Japan	O
.	O
</s>
<s>
Although	O
holographic	B-Algorithm
memory	I-Algorithm
has	O
been	O
discussed	O
since	O
the	O
1960s	O
,	O
and	O
has	O
been	O
touted	O
for	O
near-term	O
commercial	O
application	O
at	O
least	O
since	O
2001	O
,	O
it	O
has	O
yet	O
to	O
convince	O
critics	O
that	O
it	O
can	O
find	O
a	O
viable	O
market	O
.	O
</s>
<s>
As	O
of	O
2002	O
,	O
planned	O
holographic	B-Algorithm
products	O
did	O
not	O
aim	O
to	O
compete	O
head	O
to	O
head	O
with	O
hard	O
drives	O
,	O
but	O
instead	O
to	O
find	O
a	O
market	O
niche	O
based	O
on	O
virtues	O
such	O
as	O
speed	O
of	O
access	O
.	O
</s>
<s>
InPhase	B-Algorithm
Technologies	I-Algorithm
,	O
after	O
several	O
announcements	O
and	O
subsequent	O
delays	O
in	O
2006	O
and	O
2007	O
,	O
announced	O
that	O
it	O
would	O
soon	O
be	O
introducing	O
a	O
flagship	O
product	O
.	O
</s>
<s>
InPhase	B-Algorithm
went	O
out	O
of	O
business	O
in	O
February	O
2010	O
and	O
had	O
its	O
assets	O
seized	O
by	O
the	O
state	O
of	O
Colorado	O
for	O
back	O
taxes	O
.	O
</s>
<s>
The	O
assets	O
and	O
knowhow	O
of	O
InPhase	B-Algorithm
has	O
been	O
acquired	O
by	O
Apple	O
who	O
is	O
thought	O
to	O
plan	O
using	O
it	O
for	O
augmented	O
reality	O
.	O
</s>
<s>
In	O
April	O
2009	O
,	O
GE	O
Global	O
Research	O
demonstrated	O
their	O
own	O
holographic	B-Algorithm
storage	I-Algorithm
material	O
that	O
could	O
allow	O
for	O
discs	O
that	O
utilize	O
similar	O
read	O
mechanisms	O
as	O
those	O
found	O
on	O
Blu-ray	O
Disc	O
players	O
.	O
</s>
<s>
Nintendo	O
filed	O
a	O
Joint	O
Research	O
Agreement	O
with	O
InPhase	B-Algorithm
for	O
holographic	B-Algorithm
storage	I-Algorithm
in	O
2008	O
.	O
</s>
<s>
103	O
(	O
c	O
)	O
(	O
3	O
)	O
,	O
that	O
was	O
in	O
effect	O
on	O
or	O
before	O
the	O
date	O
the	O
claimed	O
invention	O
was	O
made	O
,	O
and	O
as	O
a	O
result	O
of	O
activities	O
undertaken	O
within	O
the	O
scope	O
of	O
the	O
Joint	O
Research	O
Agreement	O
,	O
by	O
or	O
on	O
the	O
behalf	O
of	O
Nintendo	O
Co.	O
,	O
and	O
InPhase	B-Algorithm
Technologies	I-Algorithm
,	O
Inc.	O
"	O
.	O
</s>
<s>
In	O
Star	B-Application
Wars	I-Application
,	O
the	O
Jedi	B-Application
use	O
holocrons	O
and	O
holographic	B-Algorithm
crystals	O
to	O
store	O
data	O
about	O
their	O
history	O
.	O
</s>
<s>
In	O
2010	O
:	O
The	O
Year	O
We	O
Make	O
Contact	O
,	O
a	O
tapeworm	O
had	O
to	O
be	O
employed	O
to	O
erase	O
HAL	O
's	O
holographic	B-Algorithm
memory	I-Algorithm
as	O
"	O
chronological	O
erasures	O
would	O
not	O
work	O
"	O
.	O
</s>
<s>
In	O
Robot	O
and	O
Frank	O
,	O
Robot	O
has	O
a	O
holographic	B-Algorithm
memory	I-Algorithm
which	O
can	O
be	O
half	O
erased	O
but	O
,	O
will	O
be	O
in	O
half	O
the	O
resolution	O
.	O
</s>
