Midinfrared optical pumping of electrons from the ground (n=1) to the first excited (n=2) subband of the quantum well produces a strongly nonthermal electron distribution which is probed spectroscopically. Two sharp induced absorption peaks appear, associated with electrons which have scattered from the upper subband via longitudinal optical (LO) phonon emission and absorption. The presence of the phonon absorption channel evidences the importance of nonequilibrium LO phonon populations (nph∼1), and the impact on the nonradiative intersubband scattering rates in quantum cascade laser devices is explored.

1.
J.
Faist
,
F.
Capasso
,
D. L.
Sivco
,
C.
Sirtori
,
A. L.
Hutchinson
, and
A. Y.
Cho
,
Science
264
,
553
(
1994
).
Google Scholar
 
2.
K. L.
Vodopyanov
,
K.
O’Neil
,
G. B.
Serapiglia
,
C. C.
Phillips
,
M.
Hopkinson
,
I.
Vurgaftman
, and
J. R.
Meyer
,
Appl. Phys. Lett.
72
,
2654
(
1998
).
Google Scholar
 
3.
P.
Harrison
and
R. W.
Kelsall
,
J. Appl. Phys.
81
,
7135
(
1997
).
Google Scholar
 
4.
D. E.
 
Nikonov
,
A.
 
Imamoglu
, and
M. O.
 
Scully
,
Phys. Rev. B
 
59
,
12212
(
1999
);
Google Scholar
 
H.
Schmidt
,
D. E.
Nikonov
,
K. L.
Campman
,
K. D.
Maranowski
,
A. C.
Gossard
, and
A.
Imamoglu
,
Laser Phys.
9
,
797
(
1999
).
Google Scholar
 
5.
G. B.
Serapiglia
,
E.
Paspalakis
,
C.
Sirtori
,
K. L.
Vodopyanov
, and
C. C.
Phillips
,
Phys. Rev. Lett.
84
,
1019
(
2000
).
Google Scholar
 
6.
J.
Faist
,
F.
Capasso
,
C.
Sirtori
,
D. L.
Sivco
,
A. L.
Hutchinson
,
S. G.
Chu
, and
A. Y.
Cho
,
Appl. Phys. Lett.
63
,
1354
(
1993
).
Google Scholar
 
7.
R.
Kaindl
,
S.
Lutgen
,
M.
Woerner
,
T.
Elsaesser
,
B.
Nottelmann
,
V. M.
Axt
,
T.
Kuhn
,
A.
Hase
, and
H.
Kunzel
,
Phys. Rev. Lett.
80
,
3575
(
1998
).
Google Scholar
 
8.
K. J.
Nash
,
M. S.
Skolnick
, and
S. J.
Bass
,
Semicond. Sci. Technol.
2
,
329
(
1987
).
Google Scholar
 
9.
M. C.
 
Marchetti
 and
W.
 
Cai
,
Phys. Rev. B
 
35
,
7725
(
1987
);
Google Scholar
 
G.
 
Paulavicius
 and
V.
 
Mitin
,
J. Appl. Phys.
 
84
,
3459
(
1998
);
Google Scholar
 
S.
Slivken
,
V. I.
Litvinov
, and
M.
Razheghi
,
J. Appl. Phys.
85
,
665
(
1999
).
Google Scholar
 
10.
B. K.
Ridley
,
Phys. Rev. B
39
,
5282
(
1989
).
Google Scholar
 
11.
K. L.
Vodopyanov
and
V.
Chazapis
,
Opt. Commun.
136
,
98
(
1997
).
Google Scholar
 
12.
K. L.
Vodopyanov
,
V.
Chazapis
, and
C. C.
Phillips
,
Appl. Phys. Lett.
69
,
3405
(
1996
).
Google Scholar
 
13.
D. E.
Nikonov
,
A.
Imamoglu
,
L. V.
Butov
, and
H.
Schmidt
,
Phys. Rev. Lett.
79
,
4633
(
1997
).
Google Scholar
 
14.
A. Yariv, Quantum Electronics (Wiley, New York, 1989).
15.
K. L.
Vodopyanov
,
V.
Chazapis
,
C. C.
Phillips
,
B.
Sung
, and
J. S.
Harris
, Jr.,
Semicond. Sci. Technol.
12
,
708
(
1997
).
Google Scholar
 
16.
S.
Lutgen
,
R.
Kaindl
,
M.
Woerner
,
T.
Elsaesser
,
A.
Hase
,
H.
Kunzel
,
M.
Gulia
,
D.
Meglio
, and
P.
Lugli
,
Phys. Rev. Lett.
77
,
3657
(
1996
).
Google Scholar
 
17.
J.
Faist
,
F.
Capasso
,
C.
Sirtori
,
D. L.
Sivco
,
A. L.
Hutchinson
,
M. S.
Hybertsen
, and
A. Y.
Cho
,
Phys. Rev. Lett.
76
,
411
(
1996
).
Google Scholar
 
This content is only available via PDF.
© 2000 American Institute of Physics.
2000
American Institute of Physics
You do not currently have access to this content.