@article {265, title = {Undressing a collective intersubband excitation in a quantum well}, journal = {Physical Review Letters}, volume = {76}, number = {13}, year = {1996}, note = {Sherwin, Mark S/Q-4762-2017
Sherwin, Mark S/0000-0002-3869-1893; Markelz, Andrea/0000-0003-0443-4319
78}, month = {Mar 25}, pages = {2382-2385}, abstract = {

We have experimentally measured the 1-2 intersubband absorption in a single 40 nm wide modulation-doped Al0.3Ga0.7As/GaAs square quantum well as a function of frequency, intensity, and charge density. The low-intensity depolarization-shifted absorption occurs near 80 cm(-1) (10 meV or 2.4 THz), nearly 30\% higher than the intersubband spacing. At higher intensities, the absorption peak shifts to lower frequencies. Our data are in good agreement with a theory proposed by Zaluzny, which attributes the redshift to a reduction in the depolarization shift as the excited subband becomes populated.

}, isbn = {0031-9007}, doi = {10.1103/PhysRevLett.76.2382}, author = {Craig, K. and Galdrikian, B. and Heyman, J. N. and Markelz, A. G. and Williams, J. B. and Sherwin, M. S. and Campman, K. and Hopkins, P. F. and Gossard, A. C.} } @proceedings {319, title = {Far-infrared harmonic generation from semiconductor heterostructures}, volume = {1854}, year = {1994}, pages = {48-55}, author = {Markelz, A.G. and Gwinn, E. G. and Sherwin, M. S. and Heyman, J. N. and Nguyen, C. and Kroemer, H.} } @article {264, title = {FAR-INFRARED SATURATION SPECTROSCOPY OF A SINGLE SQUARE-WELL}, journal = {Semiconductor Science and Technology}, volume = {9}, number = {5}, year = {1994}, note = {Sherwin, Mark S/Q-4762-2017
Sherwin, Mark S/0000-0002-3869-1893; Markelz, Andrea/0000-0003-0443-4319
S
8th International Conference on Hot Carriers in Semiconductors
Aug 16-20, 1993
Oxford univ, oxford, england
Sci \& engn res council; royal soc; brit council; oxford univ
31}, month = {May}, pages = {627-629}, abstract = {

We have performed saturation spectroscopy measurements of the lowest intersubband transition in a single 400 angstrom GaAs/Al0.3Ga0.7As modulation-doped square quantum well. We couple intense tunable far-infrared radiation from the Santa Barbara free electron laser into our sample using an edge-coupling technique and measure absorption as a function of frequency and intensity. Saturation and frequency shifts in the absorption line are clearly observed. We attribute the frequency shifts to reductions in the many-body depolarization shift. From our preliminary measurements, we estimate the intersubband relaxation time to be 600 ps to within a factor of three.

}, isbn = {0268-1242}, doi = {10.1088/0268-1242/9/5S/061}, author = {Craig, K. and Felix, C. L. and Heyman, J. N. and Markelz, A. G. and Sherwin, M. S. and Campman, K. L. and Hopkins, P. F. and Gossard, A. C.} } @article {257, title = {PROBING TERAHERTZ DYNAMICS IN SEMICONDUCTOR NANOSTRUCTURES WITH UCSB FREE-ELECTRON LASERS}, journal = {Journal of Luminescence}, volume = {60-1}, year = {1994}, note = {Sherwin, Mark S/Q-4762-2017; Guimaraes, Paulo Sergio Soares/B-6918-2012
Sherwin, Mark S/0000-0002-3869-1893; Guimaraes, Paulo Sergio Soares/0000-0002-0113-2641; Markelz, Andrea/0000-0003-0443-4319
1993 International Conference on Luminescence (ICL 93)
Aug 09-13, 1993
Univ connecticut, storrs, ct
Univ connecticut; opt soc amer; amer phys soc; ieee, laser \& electro opt soc; int union pure \& appl phys; int sci fdn; univ connecticut res fdn
3}, month = {Apr}, pages = {250-255}, abstract = {

The UCSB free-electron lasers provide kilowatts of continuously tunable radiation from 120 GHz to 4.8 THz. They have the most impact on terahertz science and technology that require a tunable, high power source to explore non-linear dynamics or that sacrifice incident power to recover the linear response of systems with very small cross-section. We describe three experiments that demonstrate the utility of these lasers in experiments on the terahertz dynamics of semiconductor nanostructures: (i) terahertz dynamics of resonant tunneling diodes, (ii) saturation spectroscopy of quantum wells and (iii) photon-assisted tunneling in superlattices.

}, isbn = {0022-2313}, doi = {10.1016/0022-2313(94)90142-2}, author = {Allen, S. J. and Craig, K. and Felix, C. L. and Guimaraes, P. and Heyman, J. N. and Kaminski, J. P. and Keay, B. J. and Markelz, A. G. and Ramian, G. and Scott, J. S. and Sherwin, M. S. and Campman, K. L. and Hopkins, P. F. and Gossard, A. C. and Chow, D. and Lui, M. and Liu, T. Y.} }