| The transverse structure of an optical field can carry a large amount of information. Such a simple concept is the basis for important technologies such as imaging and photolithography. However, some effects in nature will effectively destroy any useful transverse structure the field may possess. In this thesis, both desirable and undesirable transverse optical effects will be studied.; The ultimate limit to the amount of energy that may be usefully transmitted through a medium in a laser beam is imposed by the nonlinear response of the medium. This nonlinearity can be a thermal effect for continuous-wave or long-pulse lasers, while for short-pulse lasers will tend to be an electronic or molecular effect. Whenever the intensity-nonlinearity product is too large, the transverse structure of the beam will be so greatly distorted as to make the beam essentially useless. This beam degradation is discussed in the thesis for both the continuous-wave thermal case as well as for the short-pulse case, known as laser beam filamentation.; The undesirable effect of filamentation is a single-beam four-wave mixing effect. Similar physical processes exist for two-beam four-wave mixing. In the two-beam case, however, there is reason to believe that the generated transverse structure may possess very useful properties for applications in quantum optics. Such effects are explored in this thesis.; After discussing physical effects that can alter the transverse structure of a beam, two applications of the use of transverse structure to carry information are also explored. The first of these is coincidence imaging. This is a technique for generating an image of an object with photons that do not directly interact with the object. Experiments were performed to compare the quality of the technique when done using classical versus quantum methods.; The second application of transverse effects that is developed is a new method for generating lithographic patterns with super-resolution. The method is shown theoretically for any level of resolution improvement, and is demonstrated experimentally for up to a factor of three improvement over the traditionally accepted limit. |
