Picosecond Diagnostics in Reaching Flows Using a Mode-Locked Ti:Sapphire Laser

使用锁模钛宝石激光器进行皮秒诊断以达到流量

• 批准号: 9411391
• 负责人: Mark Linne
• 金额: $ 10.36万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-15 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9411391&HistoricalAwards=false
• 关键词: Picosecond; Diagnostics; Reaching; Flows; Using

The PI has proposed a rather innovative approach to non-intrusive laser diagnostics of reacting flows based on the use of picosecond, mode-locked TI:Sapphire laser technology. The PI enumerates many advantages of using a mode-locked laser as compared to a pulsed laser. For example, since a mode-locked laser is essentially cw in nature, consisting of trains of very short picosecond pulses at MHz repetition rates and wide band-widths, improved signal to noise can be obtained by using phase-sensitive detection and can result in the recovery of pertinent frequency spectrum information such as power spectral densities and probability density functions. The very short pulse lengths make the measurements (absorption, fluorescence) less sensitive to collisional effects and is especially useful in pump/probe measurements. Mode-locked lasers also tend to be more stable, resulting in better spatial resolution. The peak power attainable, although much less than typical pulsed lasers, nevertheless, is sufficient to perform nonlinear optical techniques in particular degenerate four wave mixing (DFWM). The PI has outlined an ambitious program which hinges on the development of a reliable high power, Fourier-transform limited laser source with pulse length in the range of 30-50 psec. The PI plans to upgrade an existing TI:Sapphire laser for this purpose. An acoustically forced turbulent flame and a high pressure laminar flame will serve as test beds for the pump/probe and DFWM diagnostics.

PI提出了一种相当创新的方法，以非侵入式激光诊断反应流的基础上使用皮秒，锁模TI：蓝宝石激光技术。 PI列举了与脉冲激光器相比使用锁模激光器的许多优点。 例如，由于锁模激光器本质上是cw的，由MHz重复率和宽带宽的非常短的皮秒脉冲串组成，通过使用相敏检测可以获得改善的信噪比，并且可以导致恢复相关的频谱信息，例如功率谱密度和概率密度函数。 非常短的脉冲长度使得测量（吸收、荧光）对碰撞效应不太敏感，并且在泵浦/探测测量中特别有用。 锁模激光器也往往更稳定，从而获得更好的空间分辨率。 可达到的峰值功率虽然远小于典型的脉冲激光器，但是足以执行非线性光学技术，特别是简并四波混频（DFWM）。 PI概述了一项雄心勃勃的计划，该计划取决于开发可靠的高功率、傅里叶变换有限激光源，脉冲长度在30-50 psec范围内。 PI计划为此升级现有的TI：Sapphire激光器。 声学强制湍流火焰和高压层流火焰将作为泵/探头和DFWM诊断的试验台。