<s>
Electron	B-Algorithm
holography	I-Algorithm
is	O
holography	B-Algorithm
with	O
electron	O
waves	O
.	O
</s>
<s>
Dennis	O
Gabor	O
invented	O
holography	B-Algorithm
in	O
1948	O
when	O
he	O
tried	O
to	O
improve	O
image	B-Algorithm
resolution	I-Algorithm
in	O
electron	O
microscope	O
.	O
</s>
<s>
The	O
first	O
attempts	O
to	O
perform	O
holography	B-Algorithm
with	O
electron	O
waves	O
were	O
made	O
by	O
Haine	O
and	O
Mulvey	O
in	O
1952	O
;	O
they	O
recorded	O
holograms	B-Algorithm
of	O
zinc	O
oxide	O
crystals	O
with	O
60keV	O
electrons	O
,	O
demonstrating	O
reconstructions	O
with	O
approximately	O
1nm	O
resolution	O
.	O
</s>
<s>
In	O
1955	O
,	O
G	O
.	O
Möllenstedt	O
and	O
H	O
.	O
Düker	O
invented	O
an	O
electron	O
biprism	O
,	O
thus	O
enabling	O
the	O
recording	O
of	O
electron	O
holograms	B-Algorithm
in	O
off-axis	O
scheme	O
.	O
</s>
<s>
There	O
are	O
many	O
different	O
possible	O
configurations	O
for	O
electron	B-Algorithm
holography	I-Algorithm
,	O
with	O
more	O
than	O
20	O
documented	O
in	O
1992	O
by	O
Cowley	O
.	O
</s>
<s>
a	O
low	O
energy	O
spread	O
)	O
of	O
the	O
electron	O
beam	O
are	O
required	O
to	O
perform	O
holographic	B-Algorithm
measurements	O
.	O
</s>
<s>
Electron	B-Algorithm
holography	I-Algorithm
with	O
high-energy	O
electrons	O
(	O
80-200keV	O
)	O
can	O
be	O
realized	O
in	O
a	O
transmission	O
electron	O
microscope	O
(	O
TEM	O
)	O
in	O
an	O
off-axis	O
scheme	O
.	O
</s>
<s>
Reconstruction	O
of	O
off-axis	O
holograms	B-Algorithm
is	O
done	O
numerically	O
and	O
it	O
consists	O
of	O
two	O
mathematical	O
transformations	O
.	O
</s>
<s>
First	O
,	O
a	O
Fourier	B-Algorithm
transform	I-Algorithm
of	O
the	O
hologram	B-Algorithm
is	O
performed	O
.	O
</s>
<s>
Original	O
holographic	B-Algorithm
scheme	O
by	O
Dennis	O
Gabor	O
is	O
inline	O
scheme	O
,	O
which	O
means	O
that	O
reference	O
and	O
object	O
wave	O
share	O
the	O
same	O
optical	O
axis	O
.	O
</s>
<s>
This	O
scheme	O
is	O
also	O
called	O
point	O
projection	O
holography	B-Algorithm
.	O
</s>
<s>
Holography	B-Algorithm
with	O
low-energy	O
electrons	O
(	O
50-1000eV	O
)	O
can	O
be	O
realized	O
in	O
in-line	O
scheme	O
.	O
</s>
<s>
Electron	B-Algorithm
holography	I-Algorithm
is	O
commonly	O
used	O
to	O
study	O
electric	O
and	O
magnetic	O
fields	O
in	O
thin	O
films	O
,	O
as	O
magnetic	O
and	O
electric	O
fields	O
can	O
shift	O
the	O
phase	O
of	O
the	O
interfering	O
wave	O
passing	O
through	O
the	O
sample	O
.	O
</s>
<s>
The	O
principle	O
of	O
electron	B-Algorithm
holography	I-Algorithm
can	O
also	O
be	O
applied	O
to	O
interference	B-Algorithm
lithography	I-Algorithm
.	O
</s>
