**2. Laser ablation**

We will focused in this section on synthesis of SWCNTs and other carbon nanomaterials via laser ablation since this is the technique used in ours laboratories. The pulsed laser ablation process for production of SWCNTs has first been reported by Guo *et al.* [16]. Nanotubes produced by laser ablation are up to 90% pure [17]. The target consists of mainly graphite to which small amounts of metal catalysts are added.

The laser ablation takes place inside a quartz tube heated to 800–1200° C [16, 18, 19] through which an ablation gas is used to control the dynamics of the plume and carry the ablation products to a cooled collector. Among the gases investigated Argon has been the most studied [16, 18, 19], but we and others proved that other gases like nitrogen [20, 21], krypton [20, 22], neon [20, 23], and helium [24] are also suitable for SWCNTs production by laser ablation.
