Nonclassical Light Generation Using a Traveling - Optical Parametric Amplifier

The quantum mechanical description of light predicts fluctuation in optical fields due to the uncertainty principle. The fluctuation, known as shot or quantum noise, limits the ultimate sensitivity of optical communication or measurement systems in which laser sources are employed. Nonclassical lights such as squeezed light or twin beams, have reduced fluctuations and have drawn particular attention over the past decades because they enable the possibility of enhancing the sensitivity of optical systems below the fundamental quantum limit. In this dissertation, nonclassical light generated from a traveling-wave optical parametric amplifier (OPA) is investigated both theoretically and experimentally. The OPA produces the quantum correlated twin beams. Phase -squeezed light and sub-Poissonian light (amplitude-squeezed state) can be generated by manipulating the twin beams using linear feed-forward control on the twin beams. Such feedforward control schemes were analyzed rigorously which are also practically realizable. The relationship between the twin beams and squeezed states was also investigated and a novel configuration was discovered in which squeezed light and a matched local oscillator are generated from the twin beams. The role of the matched local oscillator is shown to be essential in detecting the pulsed squeezed state. The generation of pulsed squeezed light and the matched local oscillator has been demonstrated experimentally. A Q-switched mode-locked Nd:YAG laser and a KTP crystal were used to build the traveling-wave OPA. Phase-sensitive and phase-insensitive characteristics were measured and compared with theory. In the squeezing experiment with the matched local oscillator, a maximum noise reduction of 5.83 +/- 0.18 dB below the vacuum noise level was obtained, which is about 4dB improvement over the previous traveling-wave pulsed squeezing experiments.