Laser pulsetrain pulse-picker for subharmonic frequencies

我们请求支持为现有的研究激光系统购买配件，其物理研究通常由NSERC发现补助金资助，光子学研究由CIPI的特殊应用资助，以及安大略卓越中心的生物物理学研究。 三名教授和五名研究生的工作将通过这笔赠款得到加强。 现有的激光系统是完整的和功能;该设备将使我们能够访问新的制度，在激光脉冲的方式进行超快激光材料相互作用时，光学，材料加工，或生物组织相互作用相关的先进和发展的激光手术。 我们最近在这个领域获得了一项专利，但进展受到资源的限制，我们已经放弃了一些领域，比如哈佛的马祖尔。 设备：一个脉冲选择器选择系统，在两个不同的激光器之间有效地共享，这将使我们能够配置我们的100 MHz激光脉冲串，以提供50 MHz，25 MHz，12 MHz或各种脉冲组合，用于输送到不同的材料或生物组织。 科学：已知飞秒激光器将存款激光能量沉积到电子中的时间尺度短于随后热化到晶格。 高重复率的激光（> 1 MHz）存款的下一个脉冲的能量电子之前，晶格能量已经完全消散，材料热松弛。 通过在这两个时间尺度范围内控制通量传递的范例，我们相信我们可以对玻璃和其他光学材料的状态进行非平衡操纵，并且在纳米尺度上做到这一点。 从本质上讲，我们希望在任何时候控制材料中电子和声子之间的能量分配-近似地，分别影响材料中的化学冲击和热/机械冲击。 我们已经证明，这使我们能够接触到新的材料科学，以及微处理不同玻璃、陶瓷和其他脆性材料的新方法。

We request support to buy accessories for an existing research-laser system, for which physics research is generally funded by NSERC Discovery grant and photonics research by funding for special applications from CIPI, as well as biophysics research by Ontario Centres of Excellence.  Three professors and five graduate students work will be enhanced by this grant.   The existing laser-system is complete and functional;  this equipment will permit us to access new regimes in the way in which laser pulses are delivered when doing ultrafast laser-materials interaction for optics, materials-processing, or biotissue interaction relevant to advanced and developmental laser surgery.  We have a recent patent in this area, but progress has been resource-limited, and we have given up some ground to groups like that of Mazur at Harvard.   The Equipment:  a pulse-picker selection system, to be efficiently shared between two different lasers, that will let us configure our 100MHz laser pulsetrain to deliver instead 50 MHz, 25 MHz, 12 MHz, or various combinations of pulses for delivery to different materials or biotissues.   The Science:  Femtosecond lasers are known to deposit laser energy into electrons on a timescale short compared to the subsequent thermalization to the lattice.  High repetition-rate lasers (> 1 MHz) deposit the next pulse of energy to electrons before this lattice-energy has fully dissipated, and the material relaxed thermally.  By the paradigm of controlling fluence delivery across these two time-scale regimes, we believe we can make non-equilibrium manipulations of the state of glasses and other optical materials, and do this at a nanometer-scale.  Essentially, we want to control, at any time, the partition of energy between electrons and phonons in the material - approximately, to influence the chemical impact and the thermal/mechanical impact in the material separately.  We've shown this gives us access to new materials science, and new ways of microprocessing different glasses, ceramics and other brittle materials.