Scientific Replicability: Two Cases of Study in Laser Physics

One of the most important characteristics of modern science is its replicability and objectivity. This means that a scientific result is taken as such only when it has been reproduced by other scientists. Indeed, the replicability of a scientific result in an objective and independent way by members of a scientific community is the cornerstone of science. Experimental laser physics is an example of “normal” science, where it is no doubt that the phenomenon could be replicated; however, the replication process may not be straightforward since it requires a good understanding of the physics behind it, as well as good technical skills. In this article, two laboratory cases of experiments on laser physics are presented: the first one deals with a Nitrogen N2 laser with a Polloni excitation circuit, and the second one deals with a transversally excited TEA carbon dioxide laser. For the nitrogen laser, it will be shown that reproducibility failed, and therefore, the reported experiment cannot be taken as a valid contribution to the advancement and understanding of nitrogen laser physics and technology. On the other hand, for the case of the TEA carbon dioxide laser, several comments are presented on the development of this finally successful experiment. Both cases show the importance of being technically up-dated in order to reproduce or improve the results reported by other researchers. Finally, a discussion about: What can we learn about the research practice from these two cases? It is presented, as well as the conclusions about the case studies; we hope they may be useful to philosophers of science and young scientists alike.