Optical power limiting of ultrashort hyper-Gaussian pulses in cascade three-level system

• 来源期刊: 中国物理B（英文版）
• 关键词: optical power limiting two-photon absorption ultrashort hyper-Gaussian pulse cascade three-level system
• 年，卷（期）: 2018,（10）
• 页码范围: 290-295
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/10/104209

摘要

Propagation of strong femtosecond hyper-Gaussian pulses in a cascade three-level molecular system is studied by solv-ing numerically the Maxwell–Bloch equations by the iterative predictor-corrector finite-difference time-domain method. Optical power limiting behavior induced by strong nonlinear two-photon absorption is observed for different orders of the femtosecond hyper-Gaussian pulses. Pulses of a higher order temporal profile are found to have a wider power range of optical limiting but a larger output saturation intensity. Both the output saturation value and the damage threshold of optical power limiting decrease with pulse duration increasing. The decrease of the pulse area along the pulse propagation is much slower than that obtained from the two-photon area theorem due to invalidity of the slowly varying amplitude approximation and the monochromatic field hypothesis.