6. The case of a single barrier
EC2
EC1 ε1 ε2
z z
ik x x ik y y −iEt/ ħ x x y y −i t
r ,t =C z e e e E y r , t=C E y0 z e e e
2
2
d 2m 2 2 d E y0 2
n z
2
2 2
2
2 E −E C z −k x −k y =0 − x − y E y0 =0
dz ħ dz 2 c2
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7. The analogy: Quantum and Optics
■ Streams of electrons ■ Streams of photons
(EM wave)
■ At interface: ■ At interface:
Reflection Reflection
Transmission Transmission
■ Interface → energy ■ Interface → refractive
barrier index difference
2 2
R=
k 1−k 2
k 1k 2 R=
n1−n2
n1n2
2 2
T=
k 2 2 k1
k 1 k 1k 2 T=
2 v 2 2 n1
1 v 1 n1n 2
1 2
I = v E0
2 7
8. Another simple case
V(x)
a x a
d 2 ħ2 d 2 E0 2
2
E =0 k E 0 =0
dx 2m dx
2
= An sin k n x E 0 = Aq sin k q x
=0 , for x=0 and x=a E 0 =0, for x =0 and x=a
n q
k n= k q=
a a
8
11. Laser: Light Amplification by Stimulated Emission of Radiation
E2
ħω ħω
ħω Active medium
E1
Active medium
a
EC
ħω
EV
11
12. Nano Laser
[1] M.T. Hill,et al., “Lasing in metallic-coated nanocavities,”
Nat Photon, vol. 1, Oct. 2007, pp. 589-594.
12
13. References
■ Datta, “Quantum Phenomena,” Modular Series on Solid State Devices, Vol VIII, Addison-
Wesley (1989). page 12-28.
■ Joannopoulus, et al., “Photonic Crystals: Molding the flow of light,” 2nd Ed, Princeton
(2008). page 22 and Appendix A. (E-book download from TWiki)
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