Speaker
Description
A non-destructive method for the technological control of the structure defects by measuring internal friction (IF) and E after laser radiation was developed. The study of influence of structure defects on damping of vibrations in Si + SiO2 plates by the diameter of D = 100÷60 mm and by the thickness of hSiO2 ≈ 600 nm, hSi ≈ 400 000 nm allows to estimate the degree of perfection of crystalline structure.
Effects of acoustic emission (AE) after nanosecond neodymium and ruby laser irradiation in fluid SiO2 are investigated. The fusion depth as the result of relaxation of photothermal elastic strains Ϭi at the large time ∂T/∂t = (55±100).109 K/sec and spatial ∂T/∂x = (1±2).104 K/sm temperature gradients on the SiO2 surface was appraised Δh ≈ 10000 nm [1]. The quantity of reflections N = τ/t ≈ 0.2 nsec/0.02 nsec = 10, approximately 10 times forward-back in specimen.
The crater fusion depth Δh at constant intensity I and laser irradiation time t is limited by the local heat-conducting and establishment of “time-equilibrium” distribution of temperature gradients ΔТ perpendicular to the crater axis and along it.
Outcomes of an evaluation of dynamic characteristics interstitial atoms Sij, vacancy V and O-complexes can be applied for account of a condition of an annealing with the purpose of deriving structural defects in SiO2 + Si after laser radiation.
REFERENCES
[1] A.P. Onanko, M.P. Kulish, Y.A. Onanko. Conference Proceedings of 2012 IEEE international conference on oxide materials for electronic engineering (OMEE), Lviv, Ukraine, 81-82 (2012). DOI: 10.1109/OMEE.2012.6464790.
| Topics | Session A. Physics of condensed matter and spectroscopy |
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