Determination of singlet-oxygen generator efficiency on a 10-kW class supersonic chemical oxygen-iodine laser (RADICL)

With the advent of the Air Force Airborne Laser program, the emphasis of chemical oxggen-iodine laser (COIL) research has shifted toward improving the overall efficiency. A key component of the COIL is the singlet-oxygen generator (SOG). To assess the efficiency of the SOG, an accurate method of determining the yield of O₂(a¹ Δ_g), [O₂(a¹Δ_g )]/[O₂(total)] where [O₂(total)]=[O₂ (a¹Δ_g)]+[O₂(X³ Σ_g^-)], has been developed. Absorption measurements of ground-state oxygen utilizing the magnetic-dipole transition, O₂(X³Σ_g^-) _(ν=0)→O₂(b¹Σ_g ⁺)_(ν=0) centered at 762 nm, have been obtained using a scanning diode laser in conjunction with a multiple-pass Herriott cell and balanced-ratiometric detection on the 10-kW class supersonic COIL (RADICL). A series of experiments was designed and conducted to test the efficiency of the SOG under various conditions