Optical parametric oscillators for ultra-sensitive intracavity phase measurements

This dissertation describes the simulation design and construction of optical parametric oscillators (OPO) for intracavity interferometry. Intracavity interferometers use two mode-locked pulses oscillating inside a cavity to perform very sensitive measurements of the phase of light. Phase changes of less than 10^-7 rad or length changes of less than 10 femtometers can be resolved. The main challenge to overcome in the execution of such a measurement is the construction of a laser or OPO with two completely independent pulses inside the cavity. To this end the concept of harmonic pumping is developed and used to construct a two pulse harmonically pumped OPO. This device demonstrates an unprecedented sensitivity and long term measurement stability. In a demonstration measurement it is used to measure the nonlinear index of refraction of lithium niobate in the near infrared. An intracavity synchronously pumped OPO is investigated as a second option for an intracavity interferometer. By placing the OPO gain crystal inside the cavity of the pump laser, higher efficiency can be reached. Since the pump pulse passes the OPO gain crystal twice in each round trip two OPO pulses are automatically created. Past realizations of this concept have however shown severe amplitude instabilities. This thesis uses an extensive computer simulation to analyze these instabilities and to develop strategies to avoid them. With this new information a stable intracavity synchronously pumped OPO and an intracavity harmonically pumped OPO are constructed. The simulation is also applied to the investigation of cavity auto stabilization with rubidium. The simulation also reveals that semiconductor lasers, due to their short excitation life time, will not suffer from instabilities when used as intracavity OPO pump lasers. A tapered amplifier semiconductor laser is constructed to pump an OPO, but is found to be unsuitable. The current state of a project to construct a vertical external cavity surface emitting semiconductor laser (VECSEL) is described.National Science Foundation, Keck FoundationPhysicsDoctoralUniversity of New Mexico. Dept. of Physics & AstronomyDiels, Jean-ClaudeGeremia, John MPrasad, SudhakarLester, Luk