Impact of pauli-blocking effect on optical limiting properties of WSe2 thin films

WSe2 thin-films as efficient optical limiters: A study on impact of annealing

“…The crystallite size increase could be attributed to the thermal expansion. The strain induced in the as-prepared thin films and their dislocation density could be estimated from this information which could be found in our previous work [29]. Using an identical recipe, we present the variation of strain and dislocation density as a function of annealing duration in Fig.…”

“…6, the on-axis peak intensity at the focal point (I 0 ) is fixed at 5.06 × 10 11 W/cm 2 . For ascertaining β, the normalized OA transmittance was fitted using the relation [29] ∆T…”

“…It could be observed that all the films exhibit a similar variation with a monotonic drop in absorbance at longer wavelengths. In addition, the electronic bandgap of films was apparently indirect and was estimated from the Tauc plot [29]. The inset in Fig.…”

“…The CA normalized transmittance for all W Se 2 thin films exhibits a pre-focal minima followed by a post-focal maxima which is a distinct signature of positive n 2 [18]. The measured normalized CA transmittance was fitted using the relation given by [29] ∆T = 1 − 4x∆φ 0 (x 2 + 9)(x 2 + 1)…”

“…where ∆φ 0 = kn 2 I 0 L ef f is the phase change due to nonlinear refraction at the focus, k=2π/λ is propagation wave vector, λ is the laser wavelength and n 2 is nonlinear refraction coefficient and ∆Ψ 0 = βI 0 L ef f /2 is phase change due to nonlinear absorption. The real part of third-order nonlinear susceptibility (χ (3) ) and n 2 are related through [29] χ…”