Physics & Astronomy ETDs

Publication Date



Lasers have been around now for over 50 years. Initially it was said that it is an invention without an application. Since then it turned out that lasers are valuable tools for applications like mapping atomic transitions or interferometric measurements. The research presented here will show one type of lasers, a two-pulse-per cavity mode-locked laser, its applications and analyze its practical and theoretical limits. An analysis of a two pulse per cavity mode-locked laser is presented as analogy to a quantum mechanical two level system. It can be shown that our lasers with two independent pulses propagating inside the cavity can be coupled via a scattering medium and will behave exactly the same way as a two level atom driven by a step function electric field. This analogy is providing a new insight into the dynamics of two-pulse coupling in mode-locked ring lasers. The most important application of a mode-locked laser with two intracavity pulses is Intra-cavity Phase Interferometry (IPI). The unique feature of mode-locked lasers, where a pulse to pulse phase shift is converted into a frequency, can be used for very sensitive phase measurements that outperform standard interferometers. Two pulse trains with the same repetition rate from the same cavity and a different phase shift will show a beatnote signal directly proportional to this phase shift when interfered on a detector. It leads to an good signal strength since all modes of the frequency comb contribute to the signal. In this dissertation, I will describe the advancement of IPI with our standard Ti:Sapphire cavities to the measurement of magnetic fields. Also another cavity, Optical Parametric oscillators (OPO) can be used for IPI. I will be showing two different implementations, intra-cavity pumped and extra-cavity pumped and their usefulness to phase interferometry by presenting a new method to measure the non-linear index of a material. In the end, a discussion about the theoretical limit of the sensitivity and resolution is provided for both, the Ti:Sapphire and OPO system.

Degree Name


Level of Degree


Department Name

Physics & Astronomy

First Committee Member (Chair)

Prasad, Sudhakar

Second Committee Member

Brueck, Steven R. J.

Third Committee Member

Sheik-Bahae, Mansoor




Mode-locked lasers, Laser interferometry, Optical pumping.

Document Type