6 research outputs found
Picosecond laser patterning of PEDOT:PSS thin films
Picosecond pulsed laser (10.4 ps, 1064 nm, 5 and 50 kHz) patterning studies were performed, of PEDOT:PSS thin films of varying thickness deposited by spin coating on glass substrates, by ablating the films or by changing locally by laser irradiation the optical and electrical properties of the polymer. From a detailed observation of the morphology of single pulse ablated holes on the surfaces of the films, in combination with simple calculations, it is concluded that photomechanical ablation is the likely ablation mechanism of the films. The single pulse ablation thresholds were measured equal to 0.13–0.18 J/cm2 for films with thicknesses in the region of ∼100–600 nm. The implications on ablation line patterning of the films using different fluences, scanning speeds and pulse repetition rates, were investigated systematically. Laser irradiation of the films before ablation induces a metal–insulator transition of the polymer because of the formation of charge localization due to a possible creation of molecular disorder in the polymer and shortening of its conjugation length
Nonlinear optical absorption in graded quantum wells modulated by electric field and intense laser field
The laser field dependence of the linear and nonlinear intersubband optical
absorption in a graded quantum well (GQW) under an applied electric field is
investigated in the effective mass approximation. In our calculations, the
position and the magnitude of the linear and total absorption coefficients
depend on the laser parameter and electric field strength. The resonant peak
of total absorption coefficient can be bleached at sufficiently high
incident optical intensities. Such a dependence of the exciting optical
intensity on the external field strengths in GQWs can be very useful for
several potential device applications