An HAS study of laser irradiation of alkali-covered dielectrics

Laser-controlled Growth of Needle-shaped Organic Nanoaggregates

“…Unfortunately the presence of the copper plate also makes it difficult to quantitatively estimate the laser-induced temperature increase in the center of the focus. If we neglect the heat sink and assume a free-standing mica, then with an irradiation time of 200 s, an absorption coefficient α = 5.8 × 10 -4 μm -1 , thermal diffusivity of κ mica = 1.6 × 10 -6 m 2 /s, and thermal conductivity of K mica = 3.1 W/Km, we calculate 12 a temperature rise in the center of the laser spot of Δ T = 69 K for P L = 550 mW. This agrees well with the temperature of T = 356 K for the thermally heated sample, where needle growth is observed (Figure b).…”