Ic. Khoo et al., Molecular photonics of a highly nonlinear organic fiber core liquid for picosecond-nanosecond optical limiting application, CHEM PHYS, 245(1-3), 1999, pp. 517-531
Recently obtained results of optical limiting studies with picosecond and n
anosecond laser pulses in a nonlinear organic fiber core liquid L34 are ana
lyzed with a model that accounts for linear, two-photon, intermediate, and
excited-state absorptions. Explicit expressions for the laser induced molec
ular level density changes, and the nonlinear transmission and optical limi
ting of picosecond laser pulses are obtained. These theoretical considerati
ons and experimental results enable us to characterize the limiting effecti
veness of L34 and several nonlinear fiber core liquids. In particular, the
roles played by two-photon, intermediate and excited-state absorptions of p
icosecond and nanosecond laser pulse pulses through ILC cored fibers and bu
lk films are thoroughly examined. In the nanosecond time scale, significant
contributions from thermal/density effects are detected. Together with new
insights into the complex intensity-dependent nonlinear transmission in th
e liquid fiber cores, we have also demonstrated the feasibility of using su
ch fiber arrays for limiting picosecond and nanosecond laser pulses to belo
w the eye/sensor damage level. (C) 1999 Elsevier Science B.V. All rights re
served.