Saturated optical nonresonant emission spectroscopy (SONRES) for atomic detection

Abstract

We have demonstrated the extremely small detection limits that can be achieved in a high‐pressure environment by the combination of saturated absorption and nonresonance emission spectroscopy. The method of SONRES exploits efficient energy transfer between excited atomic states at high pressures and intense optical fields available from tunable lasers. An estimated 10⁴ atoms/cm³ of sodium were monitored in a flame; the corresponding atomic concentration was 1 part in 10¹⁵. A detection limit of ∼10 atoms/cm³ was recorded for sodium in argon. The ultimate detection limit for this method is ∼10⁻⁴ atoms.