The absorption and photoluminescence of n‐type InP are examined as a function of free‐carrier concentration. It is found that concentration dependent band gap at 300 K is given by the empirical relation: E_g =1.344−(2.25±0.25)10⁻⁸n^1/3 (eV). The photoluminescence results are interpreted using the model taking into account nonparabolicity of the conduction band. Calculations of the peak position and photoluminescence line shape for band‐to‐band transitions are performed. Both the band filling as well as band tailing due to the Coulomb interaction of free carriers with ionized impurities and band shrinkage due to the exchange interaction between free carriers are considered in order to properly account for observed features of photoluminescence spectra. It is proposed that room temperature photoluminescence linewidth can be used for determination of the free carrier concentration in n‐type InP. This method can be used to estimate free carrier concentration ranging from 10¹⁶ to 10²⁰ cm⁻³.

In this paper we present an extensive theoretical and numerical analysis of monolithic high-index contrast grating, facilitating simple manufacture of compact mirrors for very broad spectrum of vertical-cavity surface-emitting lasers (VCSELs) emitting from ultraviolet to mid-infrared. We provide the theoretical background explaining the phenomenon of high reflectance in monolithic subwavelength gratings. In addition, by using a three-dimensional, fully vectorial optical model, verified by comparison with the experiment, we investigate the optimal parameters of high-index contrast grating enabling more than 99.99% reflectance in the diversity of photonic materials and in the broad range of wavelengths.

The article presents state of work in technology of free-space optical communications (Free Space Optics − FSO). Both commercially available optical data links and their further development are described. The main elements and operation limiting factors of FSO systems have been identified. Additionally, analyses of FSO/RF hybrid systems application are included. The main aspects of LasBITer project related to such hybrid technology for security and defence applications are presented.

A method for calculating compositional variations of energy bands of ternary alloy semiconductors based on the coherent-potential approximation is presented. A generalized, Soven-type equation in a matrix form is derived and then solved by subsequent iterations. Zeroth-order approximation for band-gap energies is taken from the virtual-crystal approximation. The nonlinear dependence of the energy upon the alloy composition at various symmetry points within the first Brillouin zone is calculated for $\mathrm{Ga}{\mathrm{As}}_{1-x}{\mathrm{P}}_x$ and ${\mathrm{Ga}}_x{\mathrm{In}}_{1-x}\mathrm{P}$ crystals. Significant band bowing has been found in both cases. The theoretical results are compared with experimental data available for these systems.

Photoluminescence measurements have been used to determine bound magnetic polaron energies in intentionally doped, high-purity p-type ${\mathrm{Cd}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$Te samples. The binding energy of acceptor-bound magnetic polarons has been found to increase with Mn content in the alloy up to about x=0.2. Beyond this value the polaron energy saturates with increasing x, as a result of the antiferromagnetic nearest-neighbor ${\mathrm{Mn}}^{2+}$-${\mathrm{Mn}}^{2+}$ interactions. This behavior and the values of polaron binding energy are in agreement with the predictions of phenomenological polaron theory, which uses the measured high-field magnetization of the host crystal as an input to determine the ${\mathrm{Mn}}^{2+}$ response.