PHOTOINDUCED LASER EFFECTS IN INDIUM NITRIDE FILM

Abstract

The optical nonlinear absorption properties in sputtering Indium nitride ( InN ) film were investigated under the excitations of nanosecond, picosecond and femtosecond pulsed lasers by open-aperture transmission Z-scan technique (TZ-scan). Under the condition of hν > Eg, the saturable absorption (SA) phenomena induced by one-photon transition were observed in both nanosecond and picosencond pulsed TZ-scan measurements. When 2hν > Eg > hν, the film presented SA due to the two-photon transition under the excitation of picosecond laser. However, at femtosecond 800 nm, the film showed the two-photon absorption (TPA) instead of SA, and the TPA coefficient tended to a saturable value as the excitation intensity increased. The results indicate that the InN film is a kind of good saturable absorber.