We propose a new type of optical spectroscopy of anisotropic semiconductor nanocrystals, which is based on the welldeveloped
stationary pump-probe technique, where the pump and probe fields are absorbed upon, respectively, interband
and intraband transitions of the nanocrystals’ electronic subsystem. We develop a general theory of intraband absorption
based on the density matrix formalism. This theory can be applied to study degenerate eigenstates of electrons in
semiconductor nanocrystals of different shapes and dimentions. We demonstrate that the angular dependence of
intraband absorption by nonspherical nanocrystals enables investigating their shape and orientation, as well as the
symmetry of quantum states excited by the probe field and selection rules of electronic transitions.
We develop a theory allowing one to calculate the energy spectra and wave functions of collective excitations in twoand
three-dimensional quantum-dot supercrystals. We derive analytical expressions for the energy spectra of twodimensional
supercrystals with different Bravias lattices, and use them to analyze the possibility of engineering the
supercrystals' band structure. We demonstrate that the variation of the supercrystal’s parameters (such as the symmetry
of the periodic lattice and the properties of the quantum dots or their environment) enables an unprecedented control over
its optical properties, thus paving a way towards the development of new nanophotonics materials.
We develop a theory of secondary emission from a single quantum dot, when the lowest-energy states of its
electron–hole pairs are involved in the photoluminescence process. For the sake of definiteness, our model allows
for two states contributing to the luminescence. We analyze the dependency of secondary emission intensity on
the energy gap between the states, while considering that the gap is determined by the quantum dot’s size. An
analytical expression for the time-dependent signal of thermalized luminescence is obtained using an analytical
solution to the kinetic Pauli equation. This expression yields the signal of stationary luminescence as the spectral
width of the excitation pulse tends to zero.