Senior Thesis

Holographic Modulation of a Pulsed UV Laser Microbeam for Biophysical Investigations of Tissue Dynamics

Albert Mao

April 26, 2004

Thesis Committee: Glenn Edwards, Daniel Kiehart (Biology Department), Ronen Plesser, Calvin Howell  (exofficio non-voting member)

ABSTRACT:  We have been using a pulsed UV laser microbeam integrated into a laser scanning confocal microscope to investigate tissue dynamics. Practical restrictions on the speed and range of manipulation for the microbeam require that the duration of exposure increase with the size and complexity of the ablated pattern. To overcome this constraint, we introduced a computer-controlled spatial light modulator (SLM) that holographically shapes the pulsed UV beam such that when focused, it can simultaneously ablate multiple areas of tissue with a single pulse. This approach was motivated by the success of similar systems that use a SLM and a confocal microscope to holographically shape single continuous-wave laser beams into dynamic arrays of optical traps. The SLM hardware used is a relatively inexpensive liquid crystal display that is available in consumer-level video projectors. Holographic microsurgery will likely have applications to the investigation of dorsal closure in Drosophila morphogenesis and other biological systems.

Here is the thesis in PDF: amao_thesis.pdf (about 3.3 MBytes)