We report the spectroscopic characterization of excited electronic states of KRb by combining spectra from molecular beam (MB) experiments with those from ultracold molecules (UM) formed by photoassociation (PA) of ultracold atoms. Spectra involving the 1¹Π, 2³Σ⁺, and b³Π states in a strongly perturbed region have been identified. This approach provides a powerful method to identify the vibrational levels of the excited electronic states perturbed globally by neighboring electronic states. This is because the two sets of spectra from the UM and the MB experiments probe the same energy region from very different initial electronic states. The UM experiments utilize high v′′ levels of the a³Σ⁺ state with large internuclear separations, while the MB experiments utilize low v′′ levels of the ground X¹Σ⁺ state with near-equilibrium internuclear separations. Only the Ω = 1 levels of the 2³Σ⁺ and b³Π states are observed in the MB spectra, while the Ω = 0⁻, 1 levels of the 2³Σ⁺ state and the Ω = 0^±, 1, 2 levels of the b³Π state are observed in the UM spectra.

In this study, optical Bloch equations with and without neighboring hyperfine states near the degenerate two-level system (DTLS) in the challenging case of $$^{85}$$85 Rb D2 transition, which involves the Doppler broadening effect, are solved. The calculated spectra agree well with the experimental results obtained based on the coupling-probe scheme with orthogonal linear polarizations of the coupling and probe fields. The mechanisms of electromagnetically induced absorption (electromagnetically induced transparency) for the open $$F_g=3 \rightarrow F_e=2$$F g = 3 → F e = 2 and 3 transitions (open $$F_g=2 \rightarrow F_e=2$$F g = 2 → F e = 2 and 3 transitions) are determined to be the effect of the strong closed $$F_g=3 \rightarrow F_e=4$$F g = 3 → F e = 4 transition line (strong closed $$F_g=2 \rightarrow F_e=1$$F g = 2 → F e = 1 transition line); this finding is based on a comparison between the calculated absorption profiles of the DTLS without neighboring states and those of all levels with neighboring states, depending on the coupling and probe power ratios. Furthermore, based on the aforementioned comparison, the crucial factors that enhance or reduce the coherence effects and lead to the transformation between electromagnetically induced absorption and electromagnetically induced transparency, are (1) the power ratios between the coupling and probe beams, (2) the openness of the excited state, and (3) effects of the neighboring states due to Doppler broadening in a real atomic system.

YBa₂(Cu_1−xM_x)₃O_7−δ films (M=Ni and Al) with up to 11 at. % dopant are fabricated on (001) SrTiO₃ substrates by codeposition of Y, BaF₂, Cu, and M, and then post‐annealing in moist oxygen. All films are 300 nm thick. They are highly oriented with the c axis perpendicular to the substrate, and their surfaces are as smooth as for undoped YBa₂Cu₃O_7−δ films. T_c(x) decreases with x consistent with bulk ceramic samples. The resistivity is metallic and ranges from 100 μΩ cm to 2.5 mΩ cm at 100 K. The residual resistivity ρ_ab(0) at T=0 K, extrapolated from ρ_ab(T) above T_c is approximately proportional to x up to 7 at. % Al films and 11 at. % Ni.

To solve the pattern recognition problem, a method of synthesized phase objects is suggested. The essence of the suggested method is that synthesized phase objects are used instead of real amplitude objects. The former is object-dependent phase distributions calculated using the iterative Fourier-transform (IFT) algorithm. The method is experimentally studied with a Vander Lugt optical-digital 4F-correlator. We present the comparative analysis of recognition results using conventional and proposed methods, estimate the sensitivity of the latter to distortions of the structure of objects, and determine the applicability limits. It is demonstrated that the proposed method allows one: (а) to simplify the procedure of choice of recognition signs (criteria); (b) to obtain one-type δ-like recognition signals irrespective of the type of objects; (с) to improve signal-to-noise ratio (SNR) for correlation signals by 20 − 30 dB on average. The spatial separation of the Fourier-spectra of objects and optical noises of the correlator by means of the superposition of the phase grating on recognition objects at the recording of holographic filters and at the matched filtering has additionally improved SNR (>10 dB) for correlation signals. To introduce recognition objects in the correlator, we use a SLM LC-R 2500 device. Matched filters are recorded on a self-developing photopolymer.