Development of a laser prototype working and testing

描述（由申请人提供）： 该项目第一阶段的主要目标将是完成可行性研究，包括设计输出波长在6.45微米范围内的闪光灯泵浦激光器，组装这种激光器，并测试其生物医学应用。在6.45微米范围内的激光发射有效地消融软组织（特别是脑组织），附带损伤最小。激光在此范围内发射的显著特征是其在蛋白质和组织水中的高吸收。通过选择脉冲宽度和波长的最佳参数，可以减少细胞长度尺度照射的附带损伤。然而，由于在红外范围内的激光发射，使与UV范围内的激光发射有关的不期望的光化学反应最小化。在6.45微米范围内的激光脉冲发射烧蚀软生物组织。该实验观察结果归因于两个过程：1）蛋白质通过酰胺II模式加热并变性，2）组织水过热并蒸发，提供爆炸力，以及3）变性蛋白质表现出脆性断裂，限制附带损伤。来自杜克大学的研究人员已经表明，有效的红外组织消融可以使用皮秒脉冲或纳秒脉冲序列来实现。为了获得相应的原型激光器参数，我们提出了一种独特的设计的新型激光源。该激光源由固体Nd：YAG激光器组成，两步拉曼转换：到1.75微米的范围，并进一步到6.45微米的范围。在第一阶段，作为潜在的外科手术工具操作的该原型激光器的输出发射的特性如下：波长：6.45微米脉冲重复频率f= 1Hz，脉冲能量：3 mJ，脉冲持续时间：12-15 ns。计划在帕萨特公司进行该激光发射与生物组织的生物物理相互作用的测试。工厂，Linthicum，马里兰州。

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.