Development of a laser prototype working and testing

DESCRIPTION (provided by applicant): The main goal in the first phase of this project will be the completion of the feasibility study, including a design of flash lamp pumped laser with an output wavelength in the range of 6.45 microm and assembling of this laser as well and its testing for biomedical applications. The laser emission at the 6.45 microm range efficiently ablates soft tissues (in particularly brain tissue) with minimal collateral damage. The distinguished feature of the laser's emission at this range is its high absorption in protein and tissue water. By selecting the optimal parameters of pulse duration and wavelength, it is possible to reduce collateral damage to cellular length scales irradiation. However, due to the lasing in the infrared range, undesirable photochemical reactions that are of concern for laser emissions in the UV range are minimized. Laser pulse emission in the range of 6.45 microm ablates soft biological tissues. This experimental observation has been attributed to two processes: 1) protein is heated via the amide II mode and denatures, 2) tissue water superheats and vaporizes, providing the explosive force, and 3) denatured protein exhibits brittle fracture, confining collateral damage. Researchers from Duke University have shown that effective infrared tissue ablation can be achieved using either: train of picosecond pulses or nanosecond pulses. In order to obtain the corresponding prototype laser parameters we propose an exclusive design of the novel laser source. This laser source consists of solid state Nd:YAG laser, 2 steps Raman conversion: to the range of 1.75 microm, and further to the range of 6.45 microm. At the first phase the characteristics of the output emission of this prototype laser, operating as a potential surgical tool is as follows: wavelength: 6.45 microm pulse repetition rate f=1 Hz, energy of pulse: 3 mJ, pulse duration: 12-15 ns. The testing of the biophysical interaction of this laser's emission with biological tissues is planned to carry out at Passat Inc. facility, Linthicum, Maryland.