Highly efficient temporal cleaner for femtosecond pulses based on cross-polarized wave generation in a dual crystal scheme

• Published in: Applied physics. B, Lasers and optics Lasers and optics, 2006-09, Vol.84 (3), p.409-414
• Main Authors: JULLIEN, A, KOURTEV, S, ALBERT, O, CHERIAUX, G, ETCHEPARE, J, MINKOVSKI, N, SALTIEL, S. M
• Format: Article
• Language: English
• Subjects: Beam trapping, self-focusing and defocusing; self-phase modulation; Cleaning; Crystals; Exact sciences and technology; Femtosecond pulses; Fundamental areas of phenomenology (including applications); Lasers; Mathematical models; Nonlinear optics; Optics; Optimization; Physics; Temporal logic; Ultrafast processes; optical pulse generation and pulse compression; Wave generation
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-006-2334-7

We present an experimental demonstration of a renewed set up, with respect to the one described in [A. Jullien et al, Opt. Lett. 30, 920 (2005)], that enables more reliable and robust performances in the increase of the contrast ratio (CR) of energetic femtosecond pulses. The new approach is based on the use of two successive crystals situated at optimum position that generate cross polarized waves whose individual effect interferes constructively. This arrangement overcomes the limitation of the single crystal schemes for temporal cleaning -- the early saturation of the transmission efficiency, previously observed when either using a relatively thick crystal or increasing intensities up to its damage threshold. A theoretical model that predicts the output CR is developed for the first time. It shows that the CR depends on the initial CR and the extinction ratio of the polarizers used. The measured temporal CR 10-10 is in accordance with theoretical predictions.