Microstructure and 355 nm Laser-Induced Damage Characteristics of Al<sub>2</sub>O<sub>3</sub> Films Irradiated with Oxygen Plasma under Different Energy

Abstract

Al 2 O 3 films were prepared using electron beam evaporation at room temperature. The samples were irradiated with oxygen plasma under different energy. The variations in average surface defect density and root mean square (RMS) surface roughness were characterized using an optical microscope and an atomic force microscope. Surface average defect density increased after plasma treatment. The RMS surface roughness of the samples decreased from 1.92 nm to 1.26 nm because of surface atom restructuring after oxygen plasma conditioning. A 355 nm laser-induced damage experiment indicated that the as-grown sample with the lowest defect density exhibited a higher laser-induced damage threshold (1.12 J/cm 2) than the other treated samples. Laser-induced damage images revealed that defect is one of the key factors that affect laser-induced damage on Al 2 O 3 films.

Laser damage properties of films with different surface accuracy of substrates

“…Many properties of the films, such as the refractive index, Electric field intensity distribution, absorption coefficients, and defect density and so on, have been subject of various publications [1][2][3][4] .…”