A. M. Prokhorov

High‐intensity laser irradiation of metallic surfaces covered by periodic structures

An analysis is performed, on the role of the periodic structures, either preexisting or induced by laser irradiation, in the process of interaction of high‐intensity laser radiation with metallic surfaces. The significance of the new results is discussed in connection with previous experimental and theoretical results reported in literature.

Early oxidation stage of copper during cw CO2 laser irradiation

The early oxidation stage of copper under the action of cw CO2 laser radiation was investigated by transmission electron microscopy, selected area diffraction, and scanning electron microscopy, in correlation with target absorptivity determinations of l0.6‐μm laser light by calorimetry. The results are discussed in connection with available theoretical interpretations.

Nitrification of zirconium by cw CO2 laser irradiation in ambient atmosphere

The preferential nitrification of zirconium can be obtained as a result of cw CO2 laser heating in air in some specific conditions, followed by rapid cooling in a jet of high purity argon.

Laser solid-phase doping of semiconductors

Abstract Physical processes that occur at nonequilibrium solid-phase diffusion of impurities into semiconductors under CW CO2 laser irradiation are studied. A number of applications of solid-phase processes stimulated by laser radiation are grounded for microelectronics, involving formation of submicron dopant layers, cleaning of dielectric coating on semiconductor wafer surfaces, making of Ohmic contacts, p-n- and heterojunctions.

Mechanism of surface compound formations by cw CO2 laser irradiation of zirconium samples in air

The structure of hard and adherent surface layers formed by cw laser irradiation in air of zirconium disks is examined by electron microscopy and x‐ray diffraction. A model is proposed for the evolution of the interaction process in this case.

Time characteristics in laser diffusion of gaseous mixtures through capillaries

New experimental results are reported pointing to the temporal characteristics of gas mixture flows of resonant and nonresonant molecules through metallic capillary tubes under the action of low‐power cw CO2 laser radiation. While a selective laser action was always observed upon resonant molecules, a special category of nonresonant molecules is introduced whose transit through the capillary is influenced besides a pure thermal action by the vibrational energy transfer from the resonant molecules.

Growth and dissolution of oxide films during laser‐assisted combustion of Ti and Zr

cw CO2 laser‐assisted combustion of Ti and Zr in Xe:O2 and N2:O2 gaseous mixtures was studied. Total dissolution of oxide films and/or formation of oxynitride layers on both metals were evidenced and the growth of giant oxide nuclei of up to 100×10×10 μm3 was observed upon burning Zr samples.

Excimer laser induced crystallization and oxidation of amorphous Cr thin films

Abstract TEM and TED results are reported on the crystallization and oxidation of 20 and 30 nm thick amorphous Cr films supported on electron microscope copper grids when submitted in air to the action of a single excimer laser pulse ( λ = 0.308 μ m) of 20 ns width (FWHM). The energy incident on the target was varied using calibrated attenuators ensuring, in spots of 0.7 to 0.9 mm diameter, laser intensities ranging from 0.6×10 5 to 1.2×10 6 W cm −2 . Crystallization phenomena are noticed beginning from 0.6×10 5 W cm −2 . Crystallization and oxidation of the thin film not involving full deterioration are seen to occur for laser spot intensities ranging from 0.17×10 6 to 0.27×10 6 W cm −2 . The copper grid meshes ( φ ≈ 120 μ m) which support the chromium thin film, channel the incident laser beam so that at mesh level in the irradiated spot, temperature gradients develop from the center of the mesh towards its borders. Thus at grid mesh level in the irradiated area, a sequence of microstructures could be noticed beginning with α-Cr small crystals followed by α-Cr and Cr 3 O 4 small crystals, Cr 3 O 4 and α-Cr 2 O 3 small crystals and finally large α-Cr 2 O 3 crystals.