A tuneable, high pulse-repetition-frequency, solid state Nd:YAG pumped titanium sapphire laser capable of generating radiation for the detection of OH, HO₂, NO and IO radicals in the atmosphere by laser induced fluorescence (LIF) has been developed. The integration of the laser system operating at 308 nm into a field measurement apparatus for the simultaneous detection of hydroxyl and hydroperoxy radicals is described, with detection limits of 3.1 × 10⁵ molecule cm⁻³ (0.012 pptv in the boundary layer) and 2.6 × 10⁶ molecule cm⁻³ (0.09 pptv) achieved for OH and HO₂ respectively (30 s signal integration, 30 s background integration, signal-to-noise ratio = 1). The system has been field tested and offers several advantages over copper vapour laser pumped dye laser systems for the detection of atmospheric OH and HO₂ radicals by LIF, with benefits of greater tuning range and ease of use coupled with reduced power consumption, instrument footprint and warm-up time. NO has been detected in the atmosphere at ∼ 1 ppbv by single photon LIF using the A ²Σ⁺ ← X ²Π_1/2 (0,0) transition at 226 nm, with absolute concentrations in good agreement with simultaneous measurements made using a chemiluminescence analyser. With some improvements in performance, particularly with regard to laser power, the theoretical detection limit for NO is projected to be ∼ 2 × 10⁶ molecule cm⁻³ (0.08 pptv). Whilst operating at 445 nm, the laser system has been used to readily detect the IO radical in the laboratory, and although it is difficult to project the sensitivity in the field, an estimate of the detection limit is < 1 × 10⁵ molecule cm⁻³ (< 0.004 pptv), well below previously measured atmospheric concentrations of IO.