Filamentation Tera-Hertz pulse generation

我们建议使用申请人实验室开发的新技术有效地产生太赫兹（THz）脉冲。它是基于强烈的飞秒（秒的万亿分之一的百万分之一）激光脉冲在空气中的自聚焦现象。自聚焦后，脉冲将自我转化为一长条锐利的焦点。我们称后者为细丝。在强飞秒激光脉冲的灯丝内传播的激光脉冲将被锁定在后者上，这样它们就会一起传播，并通过称为四波混频的物理过程产生新的电磁脉冲。后一种技术可以产生频率从紫外线到无线电频率不等的电磁脉冲。申请人和同事已经证明了该技术在可见光区域的可行性。这项新技术的专利正在申请中。该项目建议将重点放在使用相同技术产生太赫兹脉冲上。目前的合作伙伴，位于瓦尔卡地亚的加拿大国防研究与发展公司，出于安全考虑，迫切需要一种新技术来产生短程和远程脉冲，以检测诸如炭疽和爆炸物等化学和生物制剂。拟议的项目将产生新的知识和技术，并增加超快激光技术领域高素质人才的数量。

We propose to efficiently generate Tera-Hertz (THz) pulses using a new technique developed in the applicant'slaboratory. It is based upon the phenomenon of self-focusing of intense femtosecond (one millionth of atrillionth of a second) laser pulses in air. After self-focusing, the pulse will self-transform into a long streak ofsharp foci. We call the latter a filament. A laser pulse propagating inside the filament of the intensefemtosecond laser pulse will be locked on to the latter so that they propagate together and produce a newelectromagnetic pulse through a physical process called four-wave-mixing. This latter technique can produceelectromagnetic pulses whose frequencies could range from the UV to the radio frequency. The applicant andco-workers have demonstrated the feasibility of this technique in the visible region. A patent on this newtechnique is being filed. This project proposes to focus on generating THz pulses using the same technique.The current partner, Defense Research and Development of Canada in Valcartier, is in urgent need of a newtechnique to generate such pulses at short and long ranges to detect chemical and biological agents such asanthrax and explosives for the obvious reason of security. The proposed project would generate newknowledge and technology and increase the number of highly qualified personnel in the areas of ultrafast lasertechnology..