Multicomponent thin films with spectral hole burning capacity at room temperature were synthesized by using molecular beam and pulsed laser deposition techniques All materials were activated by Sm²⁺ in low-symmetry alkaline earth sites, the synthesis involved the control of ionic diffiision rate during multilayer growth and special reduction of Samarium. Enhancement of hole burning rate by 1-2 orders is obtained in nanocrystalline films as compared to bulk and microcrystalline materials New hypothetic mechanism involving the creation of Sm-defect (photochromic) centers is proposed for reversible photoburning.

The growth of thin films made from Samarium-doped alkaline earth fluoro halides (AEFH) of composition Sr_xCa_1−xFCl:Sm²⁺ (0 ⩽ x ⩽ 1) is presented and the possibilities are studied to increase significantly the inhomogeneous width of the Sm²⁺ optical zero phonon transitions. The best films were obtained when grown with a molecular beam deposition (MBD) method involving two separate molecular beams: one for the alkaline earth fluoride, the other one for the alkaline earth halide (Cl or Br). The results demonstrate that the double beam MBD technique employed is able to produce pure and mixed Matlockite films with targeted composition. The results of mainly optical studies of the samarium f–f transitions and of other complementary techniques are used to assess the composition and homogeneity of the films. With the aid of a model the composition dependence of the positions of specific optical f–f emission lines is established. Their inhomogeneous linewidth is compared with that of corresponding emission lines obtained from bulk samples of the same chemical composition. The linewidths of the films are only slightly larger (∼1.5–2 times). Thus, the film morphology cannot be exploited to increase substantially the inhomogeneous broadening of the luminescence lines. A novel approach to increase this broadening was devised, theoretically modeled and successfully tested by using multilayered sandwich-type thin films in conjunction with interdiffusion. Films with cation disorder of composition Sr_xCa_1−xFCl (x = 0.5 /0/ 0.5/ 0/..) were grown. The ⁵D₁→⁷F₀ Sm²⁺ emission linewidth is thereby increased to 70 cm^−1 full width half maximum. A width of 100cm^−1 may be obtained within the composition range x = 0, x = 1. This represents an enhancement by a factor of 3–5 in comparison with the largest values obtained in appropriate mixed bulk AEFH of constant composition. A factor >50 is gained in comparison with pure bulk AEFH hosts. The room temperature (RT) homogeneous linewidths, on the other hand, are similar to those found in bulk mixed crystals of constant composition. The intrafilm host cation diffusion during film growth of the sandwich structures was further studied. A diffusion constant of 2â‹…10^−19m²s^−1 for the Sr and Ca ions was deduced from this observation. These films are among the most promising materials for optical mass data storage through RT hole-burning.

Optical hole burning, a potential technique for spectrally selective recording, was demonstrated in Sm-doped MBE-grown thin films of CaF₂/Si(111). The inhomogeneous broadening of the corresponding Sm²⁺ 5d(T_1u) ↞ 4f(⁷F₀, A_1g) transition (690 nm) was investigated as a function of substrate temperature and film thickness. The MBE apparatus is briefly described as well as the thin film growth procedure.

Basic properties relevant to spectral hole burning (homogeneous and inhomogeneous spectral broadening, hole burning and filling mechanisms) are investigated in MeIyMeII1 − yFXIxXII1 − x: Sm2+ (Me = Ca,Sr,Ba; X = Cl,Br,I) single crystals. The relations between the spectral characteristics of 5D0,1-7F0 transitions and the material structure are described. Hole stability is investigated up to 430 K and is shown to be determined by ionic diffusion.

When modern spectral hole burning applications for high-density information storage under noncryogenic temperatures are envisioned, it is necessary to develop new frequency-selective photoactive materials for this purpose. Mixed compounds of the PbFCl family, doped with samarium(II) ions, exhibit promising and true room-temperature hole burning capabilities. We investigate this class of systems (and related ones) by combining material synthesis and high-resolution spectroscopy. Whole groups of isomorphous crystals were synthesized with varying degrees of halide anion and/or cation substitutions. Thin films of fluoride-based materials were made in a laboratory-built molecular beam epitaxy system. An extended x-ray study, differential thermal analysis, luminescence, and Raman measurements allowed the characterization of the materials. Formal models were developed for both the inhomogeneous zero-phonon optical line shapes of the samarium(II) and the time evolution of the hole burning.

We have developed a model to describe the inhomogeneous broadening of optical spectra in the substitutionally disordered crystals. The comparison with the experimentalf–f fluorescence spectra of SrFCl_xBr_1−x:Sm²⁺ (0≤x≤1) allowed to establish, in a very detailed manner, the relationship between the inhomogeneous spectral distribution and the crystal structure around the Sm²⁺ impurity.

We report on crystal growth and about physico-chemical studies on Sr_yBa_1−yFCl_xBr_1−x (y = 0, 0.5, and 1) compounds doped with Sm. Persistent spectral hole burning at 300 K is further reported on Sr_0.5Ba_0.5FCl_0.5Br_0.5:Sm single crystals.