Op to Electronics 2003

of 301 /301
ΠΟΛΥΤΕΧΝΙΟ ΚΡΗΤΗΣ ΤΜΗΜΑ ΗΛΕΚΤΡΟΝΙΚΩΝ ΜΗΧΑΝΙΚΩΝ ΚΑΙ ΜΗΧΑΝΙΚΩΝ ΥΠΟΛΟΓΙΣΤΩΝ ΕΡΓΑΣΤΗΡΙΟ ΗΛΕΚΤΡΟΝΙΚΗΣ Κωνσταντίνος Κωνσταντίνος Μπάλας Μπάλας Αν Καθηγητής Αν Καθηγητής Χανιά 2003

Embed Size (px)

Transcript of Op to Electronics 2003

2003

- E = hv = Maxwell

hc

h = 6,626 10 34 J S

P : E hv h P c = f = = c c

E = P c

Maxwell

= E x B

(1)1

Edl =

d B dt

FARADAY

dt c dt. xy dB. ac dt dB=Bac dt

. , . c.

2

d B = Bac dt

gh

3

Edl = EaE = cB

1 2 3 Ea = Bac

Faraday

(2)1

Bdl = 0 0

d E dt

Ampere

dt xz E ac dt . , dE=Eac dt.

2

d E = Eac dt

gh

3

Bdl = BaB = 0 0 Ec Ampere

1 2 3 Ba = 0 0 Eac / /

Faraday & Ampere

E = cB

0 0 cE = B

c=

1

0 0

3,00 10 8 m / s

+x

B = Bmax (k )sin (t kx ) E max = cBmax x . t = 0. E xB. x.

E = E max ( j )sin (t kx )

E = y+ B= z+

E = y B= z

-x

B = Bmax (k )sin (t + kx ) E max = cBmax t = 0 , x. x.

E = E max ( j )sin (t + kx )

E = y+ B= z

E = y B= z+

E B

1

u=

1 1 0E2 + B2 2 2 0

2

B=

E = 0 0 E c

1 2 u = 0E2dU = udV = 0 E 2 ( Ac dt ) dt . u Ac dt dt

(

)

1 dU S = = 0 cE 2 A dt S=

0 0 2 EB E2 = E = 0 0 0 01J s m2 S 1 W m2

Poynting- Poynting: S =1

0

EB

:

S=

EB

0

( P) :

P = S dA

Poynting S (W/m2) .

S=

E B

0

=

Emax Bmax

0

sin2 (t kx) =

Emax Bmax [1 cos2(t kx)] 20

E B Sav = max max 20 E2max 1 0 2 1 E max = 0cE2max = I = Sav = 20c 2 0 2

cos2(t-kx) ( )

: cE = B E = cB( Faraday) ( Ampere)

B = E

B = 0 0 cE

= k m 0 , k m =1

1 k

=

1 kk m

1

00= c k

=

c kk m

k m = 1

=

=

1

0 0c

k > 1,

u1 0 < c = 0 n c = f n=

2

1

=

n2 n1

n1 n2

1

2

(2)

(a) ( ) (b) (a) . (c) , .

(a) (b)

1. 2. r = a

= 0 a, b :

sin a nb = na sin a = nb sin b sin b na

Snell

nb > na b < a nb < na b > a

(a) . (b) .

- FERMAT: FERMAT: ( ) s1, s2, s3, ,sm n1, n2, n3, ,nm :

1 m t = = ni si c i =1 i =1 i sim

: FERMAT :

n si =1

m

i i

FRESNEL E0i, E0r E0t , , :

E r 0 r E 0i

n cos i nt cos t = i ni cos i + nt cos t

E 2ni cos i t 0 t = E ni cos i + nt cos t 0i E n cos i ni cos t r || 0 r = t E 0i || ni cos t + nt cos i E 2ni cos i t || 0t = E 0i || ni cos t + nt cos i

.. R T

E R = 0r E 0i

= r2 E 0t E 0i n cos t = t n cos i i2

2

n cos t T= t ni cos i

2 t

na > nb Snell : sin b = na > 1, b > a nb a = crit sin b = 1 na sin a nb

b = 900

sin crit =

nb na

crit = 41.10 crit = 24.40

(a) . , 900, . 1,2 3 , . (b) ( ). , -

: (Evanescent) . . (Evanescent) 1/e

, , .

(a) . (b) , LASER , , , .

:

HUYGENS (1) . ().

r = t

HUYGENS (2)

OPA=AQO r=a

Huygens .

(a) . (b) (a)

AQO : AOB :

sin a =

at

AO t sin b = b AO

sin a a = = (Snell) sin b b

c c

b a

=

nb na

(a) . (b) (a). uba, n>>m, k.

- (2) n100MHz m,k10MHz

-- , . , , . , : (stable resonator) . (unstable resonator) . :

0 g1 g 2 1

gn = 1

L Rn

Rn .

Maxwell ( , ) laser (Transversal Electric Modes). / , . , . . : . x, y :

U mk ( x, y ) = H m H k exp (x2+ y2) L Hm, Hk

Gaussian (0,0) U00(x,y) gaussian :

U 00 ( x, y ) = exp (x2+ y2) L

L w= 2

1/ 2

2z w( z ) = w1 + L

1/ 2

w(z) , w (minimal beam waste).

(divergence) laser , :

=

2 nw

n .

Laser c- Q laser : : laser. : laser. laser (LiNbO3) - (, ). . : . . () n laser : c , L d ca nL E . c = = E c = c dt nL ca n. laser Q, :

Q=

EP

=

EdE dt

= c

P E .

Q (1) ( ns ns) () Q (Q-switching). Q laser laser . , , . Q, , . F N :

N dF = F 1 N dt t

dN N = 2F dt Nt

t laser. , i, .

Q (2) Q, , : - (Pockels shells) (fast rotating galvanometric mirrors-30000rpm) ( BDN) - (LiNbO3 crystals)

(1) (mode locking) ( ps) (Gwatts.) ( n+1-n=c/2L) laser . n n, central. , =2L/c. 1/, . :

E( t ) = En exp i(( 0 + n )t + f n ) ( N/n