International audienceAtmospheric pressure plasma jets are non-thermal plasmas and have the ability to create reactive species. These features make it a very attractive tool for biomedi-cal applications. In this work, we studied NO and N 2 O production, which are two species having biomedical properties. NO plays a role in the vascularization and in ulcer treatment, while N 2 O is used as anesthetic and analgesic gas. In this study, the plasma source is similar to the COST Reference Microplasma Jet (–APPJ). Helium is used as feed gas with small admixtures of molecular nitrogen and oxygen of below 1%. The absolute densities of NO and N 2 O were measured in the effluent of an atmospheric pressure RF plasma jet by means of ex-situ quantum-cascade laser absorption spectroscopy via a multi-pass cell in Herriot configuration. We will show that the species' production is dependent on several parameters such as power, flow and oxygen and nitrogen admixture. The NO and N 2 O densities are strongly dependent on the N 2-O 2 ratio. Changing this ratio allows for choosing between a NO-rich or a N 2 O-rich regime [1]. [1] Douat et al, PSST, 25 (2016) 02502
