The optical limiting behavior of multiwalled carbon nanotube (MWCNT) powder in chloroform solution under CO(2) infrared laser irradiations is reported for, to our knowledge, the first time. Here we demonstrate the pure thermal origin of the optical limiting effect in the 160 ns time scale studied. The Z-scan technique appears to be an excellent tool for experimental evaluation of the nonlinear refractive index. An experimental model for the optical limiting behavior of MWCNT suspensions in chloroform is presented. The occurrence of a laser-induced thermal lens through the absorption of energy by the MWCNTs and subsequent heat transfer to the solvent, followed by solvent vapor bubble growth, is the main factor governing the observed drop in transmittance. Pump-probe experiments have been performed to obtain some quantitative estimation of both the rise and decay times of the thermal lensing phenomenon. It was found that the early probe signal decay, tau(1)=149 ns, was of the same order of magnitude as the rise time of the thermal lens, tau(r)=121 ns. When the nonlinear scattering was considered, a total decay time of tau=1.8 micros was obtained. A recovery time for the thermal lens of several tens of milliseconds has been experimentally determined, which is in good accordance with the theoretical value.

To our knowledge, the incorporation of nanodiamond (nD) as a reducing agent in an energetic composition has never been reported in the literature. Diamond exhibits particularly interesting physico‐chemical properties: high density, good energetic potential, and relatively low thermal sensitivity. This study proposes to demonstrate that an explosive energetic composition can be obtained by physical mixing of nD and potassium chlorate (PC). First, the energetic characteristics of this formulation were compared to those of the famous “white powder” made of PC and saccharose and discovered by the French chemist Berthollet in the 18th century. In the second part, the combustion of pelletized nD‐based mixtures initiated by a laser beam was studied by time resolved cinematography. The deflagration velocity was measured on the most energetic composition, which has a slightly negative oxygen balance (OB=−30.1%).

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