Properties of Hydrogenated GaSe Crystals

Abstract

X-ray diffraction evidence is presented for the incorporation of molecular hydrogen into GaSe crystals, which markedly reduces their c -axis resistivity and shifts the excitonic line to higher energies.

Laser crystals and ceramics: recent advances

“…mid-IR SE generation can be excited also at wavelengths of inter-Stark transitions in the 2 F 7/2 → 2 F 5/2 channel by the cascade generation principle [18,75] within the possible 5d 1 → 2 F 7/2 → 2 F 5/2 laser scheme using UV pumping in 4f 1 → 5d 1 absorption bands. Crystals doped with Pr 3+ ions permit one to excite SE at the wavelengths of their 18 generating intermanifold 4f 2 -4f 2 transitions (Fig.…”

“…The Er 3+ ions in fluoride and oxide crystals, just as for Ho 3+ ions, have spectroscopic properties that are favourable for cascade SE excitation [18,170]. This very attractive principle of laser action in activated crystals was first realized in Er 3+ ions by the direct cascade scheme 4 S 3/2 → 4 I 13/2 → 4 I 15/2 (CaF 2 -YF 3 :Er 3+ [75,178]). The overwhelming majority of cascade laser schemes have been performed with Er 3+ -and Ho 3+ -doped crystals (see also [149, 173, 179-181, 183, 184]).…”

“…9). The disposition of the energy levels and luminescence intensity properties of known generating Tm 3+ -doped crystals (Tables 1, 3, 5, and 6) allow the creation of cascade and cross-cascade [75,202,203] as well as cross-relaxation [195] laser schemes. It is also known that tunable SE in the vacuum UV region can be excited at the interconfiguration 4f 11 5d 1 -4f 12 ed-allowed transition of Tm 3+ ions in several anisotropic fluoride crystals [204].…”

Stimulated-emission spectroscopy of fine-grained “garnet” ceramics Nd3+:Y3Al5O12in a wide temperature range between 77 and 650 K

“…All of them basically govern by different manifestations of electron-phonon interaction and crystal-field parameters (splitting of Stark levels and transition probabilities between them), etc. The temperature effects with sudden switching of lasing wavelengths were recorded in many Nd 3+ -doped crystals, for example, in temperature range above 300 K in CaF 2 [7], SrF 2 [8], and LaF 3 [9] a) The numeration line here and in Fig. 3 is the same.…”

Laser and nonlinear-laser properties of undoped and Nd3+-doped orthorhombic Ca(NbO3)2single crystals: new stimulated-emission performance and high-order picosecond stimulated Raman scattering covering more than two octave Stokes and anti-Stokes wavelengths

“…All these SE wavelengths (see Fig. 7 in [22]) were recorded by the use of combined active media [25] the melt were obtained with the stoichiometric amounts of Ti 4+ charge compensators. All calcium niobates were pulled (rate ≈ 6 mm/h and rotation ≈ 30 min −1 ) in air using an Ir crucible.…”