Laboratory of Semiconductor Optoelectronics
Members of the group:
- Nonlinear optical properties of semiconductors and semiconductor
- Strong optical nonlinearities in semiconductor quantum wires and dots.
- Gain and laser emission of semiconductor quantum wires and dots.
- Optical bistability in semiconductors and semiconductor nanostructures.
- Optical and nonlinear optical properties of porous silicon.
- Ultrafast transient processes and mechanisms of relaxation in
semiconductors with reduced dimensionality.
- The method of picosecond laser saturation spectroscopy has been applied
to investigate the energy spectra of semiconductor quantum dots and wires
with essential size dispersion that smears out all peculiarities of the
linear absorption spectra that should arise due to the quantum confinement.
The application of picosecond laser has allowed to excite basically
nanostructures which absorb its radiation resonantly. The saturation of
discrete optical transitions can be resolved.
- Discrete optical transitions between the energy levels of size
quantization in quantum dots and wires have been observed in the samples with
great dispersion of the size of nanostructures using picosecond laser
saturation spectroscopy method.
- The gain at the frequency of the lower optical transitions between the
energy levels of size quantization has been observed for the first time in
semiconductor quantum dots.
- The first observation of stimulated emission at the frequency of the
quantum dot lower optical transition and lasing in Fabry-Perot resonator
made of glass containing CdSe quantum dots.
- Discrete optical transitions that arise due to quantum confinement and
strong optical nonlinearities have been registered in quantum wires and dots
of porous silicon.
- Nonlinear optical absorption at discrete frequencies (bleaching bands)
has been observed for GaAs quantum wires in crysotile asbestos nanotubes
with average diameter 6 nm. The induced decrease of absorption has been
explained by filling of the size-quantized energy levels of quantum wires
with nonequilibrium carriers (saturation effect).
- A considerable slowing down of energy relaxation in quantum dots of CdSe
and in quantum wires and dots of porous Si compared with intraband relaxation
in the bulk has been observed.
- Preliminary measurements of the first samples of CdS nanostructures
crystallized in molecular filters with different lateral dimensions of the
channels have shown that the peculiarities in optical spectra arise due to
quantum confinement in nanostructures of the designed size.
The picosecond laser spectroscopy methods utilizing different types of
powerful picosecond lasers, optical multichannel analyzers, modern streak
cameras, photon counting technique, cryogenic technique, etc. are used in
- V.S. Dneprovskii, V.I. Klimov, D.K. Okorokov and Yu.V. Vandyshev. Strong
optical nonlinearities and laser emission of semiconductor microcrystals.
Solid State Commun. 81, 227 (1992).
- Yu.V. Vandyshev, V.S. Dneprovskii, V.I. Klimov and D.K. Okorokov. Lasing
on a transition between quantum-well levels in a quantum dot.
Pis'ma v Zh.Eksp.Teor.Fiz. 54, 441 (1991).
- V. Dneprovskii, N. Gushina, D. Okorokov, V. Karavanskii and E. Dovidenko.
Saturation of optical transitions in quantum dots and wires of porous
silicon. Superlattices and Microstructures 17, 41 (1995).
- V.I. Klimov, V.S. Dneprovskii and V.A. Karavanskii. Nonlinear-transmission
spectra of porous silicon: Manifestation of size quantization.
Appl.Phys.Lett. 64 (20), 2691 (1994).
- V. Dneprovskii, A. Ejov, N. Gushina, D. Okorokov, V. Panov, V. Karavanskii,
A. Maslov, V. Sokolov and E. Dovidenko. Strong Optical Nonlinearities in
Quantum Wires and Dots of Porous Silicon. Phys.Stat.Sol. (b) 188,
- V. Dneprovskii, N. Gushina, O. Pavlov, V. Poborchii, I. Salamatina and
E. Zhukov. Nonlinear optical absorption of GaAs quantum wires.
Phys.Lett.A 204, 59 (1995).
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