Quantum-cascade lasers operating above 20 μm (at λ∼21.5 μm and λ∼24 μm) wavelength are reported. Pulsed operation was obtained up to 140 K and with a peak power of a few milliwatts at cryogenic temperatures. Laser action originates from interminiband transitions in “chirped” superlattice active regions. The waveguides are based on surface-plasmon modes confined at a metal–semiconductor interface. The wavelengths were chosen in order to avoid major phonon absorption bands, which are particularly strong at energies just above the reststrahlen band. We also report on a 21.5-μm-wavelength laser based on a two-sided interface-plasmon waveguide.

1.
C.
Gmachl
,
F.
Capasso
,
R.
Köhler
,
A.
Tredicucci
,
A. L.
Hutchinson
,
D. L.
Sivco
,
J. N.
Baillargeon
, and
A. Y.
Cho
,
IEEE Circuits Devices Mag.
16
,
10
(
2000
).
2.
R.
Paiella
,
F.
Capasso
,
C.
Gmachl
,
C. G.
Bethea
,
D. L.
Sivco
,
J. N.
Baillargeon
,
A. L.
Hutchinson
,
A. Y.
Cho
, and
H. C.
Liu
,
IEEE Photonics Technol. Lett.
12
,
780
(
2000
).
3.
R.
Paiella
,
F.
Capasso
,
C.
Gmachl
,
D. L.
Sivco
,
J. N.
Baillargeon
,
A. L.
Hutchinson
,
A. Y.
Cho
, and
H. C.
Liu
,
Science
290
,
1739
(
2000
).
4.
C.
Sirtori
,
P.
Kruck
,
S.
Barbieri
,
P.
Collot
,
J.
Nagle
,
M.
Beck
,
J.
Faist
, and
U.
Oesterle
,
Appl. Phys. Lett.
73
,
3486
(
1988
).
5.
C.
Gmachl
,
H. M.
Ng
, and
A. Y.
Cho
,
Appl. Phys. Lett.
77
,
334
(
2000
).
6.
M.
Rochat
,
J.
Faist
,
M.
Beck
,
U.
Oesterle
, and
Marc
Ilegems
,
Appl. Phys. Lett.
73
,
3724
(
1998
).
7.
E. S.
Koteles
and
W. R.
Datars
,
Can. J. Phys.
54
,
1676
(
1974
);
E. S.
Koteles
and
W. R.
Datars
,
Solid State Commun.
19
,
221
(
1976
).
8.
A.
Tredicucci
,
C.
Gmachl
,
F.
Capasso
,
D. L.
Sivco
,
A. L.
Hutchinson
, and
A. Y.
Cho
,
Appl. Phys. Lett.
76
,
2164
(
2000
), and references therein.
9.
A.
Tredicucci
,
F.
Capasso
,
C.
Gmachl
,
D. L.
Sivco
,
A. L.
Hutchinson
, and
A. Y.
Cho
,
Appl. Phys. Lett.
73
,
2101
(
1998
).
10.
C.
Sirtori
,
F.
Capasso
,
J.
Faist
, and
S.
Scandolo
,
Phys. Rev. B
50
,
8663
(
1994
).
11.
R.
Colombelli
,
F.
Capasso
,
C.
Gmachl
,
A.
Tredicucci
,
A. M.
Sergent
,
A. L.
Hutchinson
,
D. L.
Sivco
, and
A. Y.
Cho
,
Appl. Phys. Lett.
77
,
3893
(
2000
), and references therein.
12.
Nonradiative scattering times are calculated considering LO phonon emission only.
13.
C.
Sirtori
,
C.
Gmachl
,
F.
Capasso
,
J.
Faist
,
D. L.
Sivco
,
A. L.
Hutchinson
, and
A. Y.
Cho
,
Opt. Lett.
23
,
1366
(
1998
).
14.
A.
Tredicucci
,
F.
Capasso
,
C.
Gmachl
,
D. L.
Sivco
,
A. L.
Hutchinson
, and
A. Y.
Cho
,
Appl. Phys. Lett.
73
,
2101
(
1998
).
15.
A.
Tredicucci
,
C.
Gmachl
,
M. W.
Wanke
,
F.
Capasso
,
A. L.
Hutchinson
,
D. L.
Sivco
,
S. G.
Chu
, and
A. Y.
Cho
,
Appl. Phys. Lett.
77
,
2286
(
2000
).
This content is only available via PDF.
You do not currently have access to this content.