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Opto-Electronics and Photonics Woo-Young Choi Dept. of Electrical and Electronic Engineering Yonsei University Lecture 8: Normal Incidence at Dielectric Interface

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  • Opto-Electronics and

    Photonics

    Woo-Young Choi

    Dept. of Electrical and Electronic EngineeringYonsei University

    Lecture 8: Normal Incidence at Dielectric Interface

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    0 1exp( ) ,iE yE j zb= -

    Unknowns:

    rE

    11

    11

    ,,hbme

    iE22

    22

    ,,hbme

    tE

    x

    zy

    rH =

    iH =

    tE =

    rE =

    22

    exp( )ttEH x j zbh

    = - -

    0s =

    (Cheng 8-8)

    01

    1

    exp( )Ex j zbh

    - -

    11

    exp( )rEx j zbh

    Er, Et

    1exp( ) ,ryE j zb

    2exp( ) ,tyE j zb-

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    0 1exp( ) ,iE yE j zb= -

    1) Etan should be continuous at z=0

    rE

    11

    11

    ,,hbme

    iE22

    22

    ,,hbme

    tE

    : reflection coef.: transmission coef .t

    G

    x

    zy

    11

    exp( )rrEH x j zbh

    =

    01

    1

    exp( )iEH x j zbh

    = - -

    2exp( ) ,t tE yE j zb= -

    1exp( ) ,r rE yE j zb=

    22

    exp( )ttEH x j zbh

    = - -

    0 r tE E E+ =

    0 0Define , and r tE E E Et= G =

    1 tÞ + G =

    B.C.’s

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    2) Htan should be continuous at z=0

    2 1( )n sa H H J´ - =

    i r tH H H+ =

    12

    2

    12

    12 2, ηηητηη

    ηη+

    =+-

    =G

    0=

    rE

    11

    11

    ,,hbme

    iE22

    22

    ,,hbme

    tE

    11

    exp( )rrEH x j zbh

    =

    01

    1

    exp( )iEH x j zbh

    = - -

    22

    exp( )ttEH x j zbh

    = - -

    0

    1 1 2

    trE EEh h h

    - + = -

    1 1 2

    1 ,th h h

    G\- + = - (1 )t+ G =

    0s =

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    rE

    11

    11

    ,,hbme

    iE22

    22

    ,,hbme

    tE

    G =

    mhe

    =

    12

    2

    12

    12 2, ηηητηη

    ηη+

    =+-

    =G

    In dielectric materials,

    0m m= e = 0re e2

    0n e=

    n: refractive index1me

    =0 0

    1n m e

    2 1

    2 1

    2 1

    2 1

    m me em me e

    -

    -

    2 0 1 0

    2 0 1 0

    1 1 1 1

    1 1 1 1n n

    n n

    e e

    e e

    -=

    +

    1 2

    1 2

    ,n nn n

    -=

    +1

    1 2

    2nn n

    t =+

    0nb w me b= =

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    rE

    1n

    iE

    2n

    tEMax. :G

    :t

    1, 1 2n n>>

    Min. :G:t

    -1, 1 2n n

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    Incident and Transmitted waves

    Reflected and Transmitted waves

    rE

    1 1n =

    iE

    2 2n =

    tE

    1 2

    1 2

    n nn n

    -G =

    +13

    = -

    1

    1 2

    2nn n

    t =+

    23

    =

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    Total waves

    rE

    1 1n =

    iE

    2 2n =

    tE

    1 2

    1 2

    n nn n

    -G =

    +13

    = -

    1

    1 2

    2nn n

    t =+

    23

    =

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    Total E-field for z

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    1 0 1 00( 0) ( )

    jn z jn ztotalE z yE e e

    b b-< = + G

    totalE =

    G+1

    G-1

    z02λ-

    1 0 1 020 (1 )

    jn z j n zyE e eb b-= + G

    1 020 1

    j n zE e b+ G

    Im

    )0(1

    =G+

    zG-1

    0

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    Total H-field for z

  • Opto-Electronics and Photonics (2020/2) W.-Y. Choi

    Lecture 8: Normal Incidence at Dielectric Interface

    Homework (Due 9/28)

    1( Re )2av

    P E H *é ù= ´ë û

    Determine the vector expression for the average power density propagation.