<s>
Quantum	B-Algorithm
lithography	I-Algorithm
is	O
a	O
type	O
of	O
photolithography	B-Algorithm
,	O
which	O
exploits	O
non-classical	O
properties	O
of	O
the	O
photons	O
,	O
such	O
as	O
quantum	O
entanglement	O
,	O
in	O
order	O
to	O
achieve	O
superior	O
performance	O
over	O
ordinary	O
classical	O
lithography	O
.	O
</s>
<s>
Quantum	B-Algorithm
lithography	I-Algorithm
is	O
closely	O
related	O
to	O
the	O
fields	O
of	O
quantum	O
imaging	O
,	O
quantum	O
metrology	O
,	O
and	O
quantum	B-Algorithm
sensing	I-Algorithm
.	O
</s>
<s>
Quantum	B-Algorithm
lithography	I-Algorithm
was	O
invented	O
at	O
Jonathan	O
P	O
.	O
Dowling	O
's	O
group	O
at	O
JPL	O
,	O
and	O
has	O
been	O
studied	O
by	O
a	O
number	O
of	O
groups	O
.	O
</s>
<s>
Of	O
particular	O
importance	O
,	O
quantum	B-Algorithm
lithography	I-Algorithm
can	O
beat	O
the	O
classical	O
Rayleigh	O
criterion	O
for	O
the	O
diffraction	O
limit	O
.	O
</s>
<s>
Classical	O
photolithography	B-Algorithm
has	O
an	O
optical	B-Algorithm
imaging	I-Algorithm
resolution	O
that	O
cannot	O
be	O
smaller	O
than	O
the	O
wavelength	O
of	O
light	O
used	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
the	O
use	O
of	O
photolithography	B-Algorithm
to	O
mass-produce	O
computer	O
chips	O
,	O
it	O
is	O
desirable	O
to	O
produce	O
smaller	O
and	O
smaller	O
features	O
on	O
the	O
chip	O
,	O
which	O
classically	O
requires	O
moving	O
to	O
smaller	O
and	O
smaller	O
wavelengths	O
(	O
ultraviolet	O
and	O
x-ray	O
)	O
,	O
which	O
entails	O
exponentially	O
greater	O
cost	O
to	O
produce	O
the	O
optical	B-Algorithm
imaging	I-Algorithm
systems	O
at	O
these	O
extremely	O
short	O
optical	O
wavelengths	O
.	O
</s>
<s>
Quantum	B-Algorithm
lithography	I-Algorithm
exploits	O
the	O
quantum	O
entanglement	O
between	O
specially	O
prepared	O
photons	O
in	O
the	O
NOON	O
state	O
and	O
special	O
photoresists	O
,	O
that	O
display	O
multi-photon	O
absorption	O
processes	O
to	O
achieve	O
the	O
smaller	O
resolution	O
without	O
the	O
requirement	O
of	O
shorter	O
wavelengths	O
.	O
</s>
<s>
The	O
field	O
of	O
quantum	B-Algorithm
lithography	I-Algorithm
is	O
in	O
its	O
infancy	O
,	O
and	O
although	O
experimental	O
proofs	O
of	O
principle	O
have	O
been	O
carried	O
out	O
using	O
the	O
Hong	O
–	O
Ou	O
–	O
Mandel	O
effect	O
,	O
it	O
is	O
still	O
a	O
long	O
way	O
from	O
practical	O
uses	O
.	O
</s>
