Michail P. Frolov

Singlet delta oxygen production in self-sustained and non-self-sustained slab discharges

Singlet delta oxygen O2(a1Δg) (SDO) production in a slab discharges ignited in oxygen gas mixtures was experimentally studied. An influence of gas mixture content and input electric power on SDO yield was analyzed. In self-sustained RF slab discharge SDO yield of 10±5% was measured by comparison luminescence intensity of SDO going from a chemical generator and SDO generated in electric discharge. SDO yield of 7.2% was measured by intracavity laser spectroscopy method. It was demonstrated that the choice of electrodes material is very important. Experiments on SDO production in slab non-self-sustained discharge with external ionization by repeating high-voltage pulses were carried out. SDO concentration was measured by the method of intracavity laser spectroscopy. The measured concentration of SDO was about 1.5 1016 cm-3, with SDO yield of ~10.6%. A development of electric discharge oxygen-iodine laser with SDO production in long electrodes slab discharge is discussed.

Room-temperature Fe2+: ZnS single crystal laser pumped by an electric-discharge HF laser

A room-temperature laser based on a single crystal has been studied. The crystal was pumped by a nonchain electric-discharge HF laser with a light pulse FWHM of . The pump spot diameter on the crystal surface varied from 3.9 to . The slope efficiency at these values of was 37% – 39 %, respectively. The maximum laser energy was (at ) with the total efficiency with respect to the absorbed pump energy of . A further increase in the laser energy was not achieved because the crystal was destroyed at an incident pump energy and power of and , respectively. The damaged region has a form of a long narrow channel shifted from the entrance surface inside the active element.

Cr:ZnSe laser with 0.03 Hz/Hz 1/2 frequency noise for compact methane based OFS

The mid-IR cw tunable solid state Cr²⁺:ZnSe laser with spectral density of intrinsic frequency noise less than 30 mHz/Hz^1/2 was created. The laser was applied for sub-Doppler spectroscopy of (ν<inf>1</inf>+ν<inf>4</inf>) vibrational-rotational band of methane and narrow resonances of saturated dispersion at λ = 2.36 µm were demonstrated for the first time. Characteristics of resonances and low frequency noise of the laser pave the way to a short-term frequency stability at the level of 10⁻¹⁵ – 10⁻¹⁶.

Electric properties, spectroscopy, and singlet delta oxygen yield of electron-beam sustained discharge in oxygen gas mixtures

Electric properties and spectroscopy of an e-beam sustained discharge (EBSD) in oxygen and oxygen gas mixtures at gas pressures up to 100 Torr was experimentally studied in large excitation volume (~18 liter). The discharge in pure oxygen and its mixtures with noble gases was shown to be very unstable and characterized by low input energy. When adding small amount of carbon monoxide or hydrogen, the electric stability of the discharge increases, specific input energy per molecular component being higher more than order of magnitude and coming up to 6.5 kJ/(l atm). Theoretical calculations demonstrated that for the experimental conditions the singlet delta oxygen yield may reach ~20% exceeding its threshold value needed for oxygen-iodine laser operation at room temperature. The results of experiments on spectroscopy of the singlet delta and singlet sigma oxygen states in the EBSD are presented.

Spectral dynamics of a multimode Co:MgF2 laser with intracavity absorption

Spectral dynamics of a cw Co:MgF2 laser with intracavity absorption is recorded in the spectral range around 2 μm. Sensitivity to intracavity absorption corresponds to the absorption path length of 1200 km. New absorption lines of methane are detected.