This project will be concerned with the generation, measurement and application of light with sub- Poissonian statistics, normally called squeezed light. The squeezed light will be generated by use of all solid state diode-pumped light sources producing ultrashort pulses. This light will be frequency doubled and parametrically down-converted to produce squeezed light. This tuneable source of squeezed light will then be used to investigate nonlinear optical and atomic processes. In particular, the efficiency of harmonic generation and of Doppler-free two-photon excitation of Rb atoms will be investigated as a function of the quantum statistics of the illuminating radiation. Further, novel effects of the interaction of squeezed light with cooled and trapped atoms will be explored.