Nonlinear absorption properties of Co2+:MgAl2O4 crystal

The differential absorption spectra of Co²⁺: MgAl₂O₄ (MALO) crystal were studied with a picosecond pump-probe technique under excitation of the ⁴A₂→⁴T₁(⁴P) and ⁴A₂→⁴T₁(⁴F) transitions of the tetrahedral Co²⁺ ion. The difference spectra of stimulated emission (SE) and excited state absorption (ESA) were derived from the measured differential absorption spectra. The ⁴T₁(⁴P)→⁴A₂ SE band around 660 nm was observed. The ESA bands were assigned to the ⁴T₂→⁴T₁(⁴P) transition and to transitions from the thermally populated ²E(²G) excited state to doublet levels arising from the ²F free-ion level of the tetrahedrally coordinated Co²⁺ ion. Absorption saturation measurements were performed at 1.34 μm and 1.54 μm. Passive Q-switching of 1.34-μm Nd³⁺:YAlO₃ and 1.54-μm Er³⁺:glass lasers was realized using the Co²⁺:MALO crystal as saturable absorber. The Q-switched laser pulses of 38 ns (110 ns) in duration and up to 2.7 mJ (10 mJ) in energy at 1.54 μm (1.34 μm) were obtained. Received: 3 March 1999 / Revised version: 30 June 1999 / Published online: 30 November 1999     

Upgraded control system of scintillation counters at CDF II muon trigger

Scintillation counters are an important part of the muon detection system at CDF II (FNAL, United States). Permanently controlling and maintaining the high performance of these detectors are essential for obtaining high-quality experimental data. The first version of the control system of scintillation counters created in 2001 was completely upgraded by us due to increased requirements for the control systems of subsystems at CDF in connection with the growth of Tevatron luminosity, the introduction of new devices, and the experience of operation.     

Optical transient bleaching/absorption of surface-oxidized CuInS2 nanocrystals

2 nanocrystals in a polymer film have been studied with the picosecond pump-probe technique. The oxidized CuInS₂ nanocrystals have an additional absorption band with a peak at 1.03 eV, which is bleached under picosecond excitation. Rapid (∼50 ps) trapping into midgap surface states results in long-lived (≫300 ps) bleaching and induced absorption features. A schematical energy-level diagram for oxidized CuInS₂ nanocrystals is given based on the experimental results. Received: 7 January 1997/Revised version: 16 April 1997     

Local magnetic properties of Fe3(CrxCo1−x) ferromagnetic alloys

Both experimental and theoretical methods are used to obtain information on the local magnetic moments of atoms of all components of Fe-Cr-Co ferromagnetic alloys, which are important in practice.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 5–10, November, 1989.     

Picosecond laser complex for investigation of nonlinear transmittance of saturated absorbers

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 5, pp. 866–870, May, 1991.