LASERs - SMU
17
LASERs Ali Almuslim
Transcript of LASERs - SMU
LASER
s
Ali A
lmu
slim
The
De
finitio
n o
f LASER
�A
Ligh
t Am
plific
atio
n b
y Stimu
late
d Em
ission
of R
ad
iatio
n
�Th
e w
ord
lase
me
an
s
�To
ab
sorb
en
erg
y in o
ne
form
�To
em
it a n
ew
form
of lig
ht e
ne
rgy th
at is m
ore
use
ful
Histo
ry of LA
SER�
In 1917, A
lbe
rt Einste
in c
rea
ted
th
e fo
un
da
tion
for th
e LA
SER
�In
1958, Ch
arle
s Tow
ne
s an
d
Arth
ur Sc
ha
wlo
w fo
un
d
the
ore
tica
l ba
sis for LA
SER
�In
1960, The
od
ore
Ma
ima
n b
uilt th
e first
LASER
by u
sing
a ru
by c
rystal m
ed
ium
�R
ub
y crysta
l is co
mp
ose
d o
f a
lum
inu
m o
xide
, wh
ere
som
e o
f th
e a
lum
inu
m a
tom
s ha
ve b
ee
n
rep
lac
ed
with
ch
rom
ium
ato
ms.
Ch
rom
ium
give
s the
rub
y its vib
ran
t red
co
lor
�In
a ru
by la
ser, a
rub
y crysta
l is fo
rme
d in
to a
cylin
de
r. A fu
lly re
flec
ting
mirro
r is pla
ce
d o
n o
ne
e
nd
an
d a
pa
rtially re
flec
ting
m
irror o
n th
e o
the
r.
�A
hig
h-in
ten
sity lam
p is sp
irale
d
aro
un
d th
e ru
by c
ylind
er to
p
rovid
e a
flash
of w
hite
ligh
t tha
t trig
ge
rs the
lase
r ac
tion
.
Prop
ertie
s of La
ser
�M
on
oc
hro
ma
tic
�Em
it on
ly on
e w
ave
len
gth
�C
oh
ere
nc
e
�A
ll the
em
itted
ph
oto
ns b
ea
r a
co
nsta
nt p
ha
se re
latio
nsh
ip w
ith
ea
ch
oth
er in
bo
th tim
e a
nd
p
ha
se
�C
ollim
ate
d
�Tra
velIn
on
e d
irec
tion
LASER
Vs. LIG
HT
Ho
w LA
SER is Pro
du
ce
d?
�LA
SER is a
form
of e
ne
rgy a
t wh
ich
th
e h
um
an
eye
is sen
sitive.
�LA
SER a
s ele
ctro
ma
gn
etic
wa
ves
em
itting
rad
ian
t en
erg
y in tin
y p
ac
kag
e.
�Ea
ch
ph
oto
n h
as a
ch
ara
cte
ristic
freq
ue
nc
y an
d its e
ne
rgy is
pro
po
rtion
al to
its freq
ue
nc
y
Einste
in’s q
ua
ntu
m th
eo
ry of ra
dia
tion
In 1917, a
cc
ord
ing
to
Einste
in, th
e in
tera
ctio
n o
f ra
dia
tion
with
ma
tter
co
uld
be
exp
lain
ed
in
term
s of th
ree
ba
sics
pro
ce
ss:
�A
bso
rptio
n
�Sp
on
tan
eo
us Em
ission
�Stim
ula
ted
Emissio
n
Ab
sorp
tion
As w
e kn
ow
the
am
ou
nt
of e
ne
rgy (E) c
an
be
d
ete
rmin
ed
by th
e
eq
ua
tion
:E=hv
wh
ere
his Pla
nc
k’s co
nsta
nt
(6.63×1024J/SEC
) an
d V
is the
ph
oto
n
freq
ue
nc
y. This p
roc
ess, w
he
reb
y a
tom
ic e
xcita
tion
oc
cu
rs du
e to
the
m
ove
me
nt o
f an
ele
ctro
n fro
m its
gro
un
d sta
te to
a h
igh
-en
erg
y orb
ital
is term
ed
‘ab
sorp
tion
’.
Spo
nta
ne
ou
s Emissio
n
�It is a
pro
ce
ss in w
hic
h th
ere
is an
em
ission
of a
ph
oto
n w
he
ne
ver a
n a
tom
tra
nsm
its from
a h
igh
er e
ne
rgy sta
te to
low
er e
ne
rgy sta
te w
itho
ut th
e a
id
of a
ny e
xtern
al a
ge
nc
y
Stimu
late
d Em
ission
�Stim
ula
ted
Emissio
n is th
e b
asis o
f the
LASER
pro
du
ctio
n
�It’s a
pro
ce
ss in w
hic
h th
ere
is an
em
ission
of a
ph
oto
n w
he
ne
ver a
n a
tom
tra
nsits fro
m a
hig
he
r en
erg
y leve
l to lo
we
r en
erg
y leve
l un
de
r the
influ
en
ce
o
f an
exte
rna
l ag
en
cy like
ind
uc
ing
ph
oto
n.
Ap
plic
atio
ns o
f LASER
�In
du
stry:
•C
uttin
g a
nd
we
ldin
g
•G
uid
an
ce
system
s ( test th
e
qu
ality o
f ma
teria
ls)
�M
ed
icin
e:
•La
ser sc
alp
el
•Eye
surg
ery
�Sc
ien
ce
:
�Sp
ec
trosc
op
y
�Pre
cise
me
asu
rem
en
ts
�R
ad
ars
�C
on
sum
er:
•La
ser lig
hts
•C
Ds a
nd
DV
Ds
Tha
nks fo
r you
r listen
ing
Sou
rce
s
oh
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