Practical Techniques for the Measurement of Ultrashort Laser Pulses

超短激光脉冲测量实用技术

• 批准号: 9988706
• 负责人: Rick Trebino
• 金额: $ 27万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9988706&HistoricalAwards=false
• 关键词: Practical; Techniques; Measurement; Ultrashort; Laser

The measurement of ultrashort laser pulses remains an arduous task. Theautocorrelator, the device of choice for decades, is complex, comprising many components. The pulse must be split into two; the two pulses must then be spatially and temporally overlapped in a carefully alignedsecond-harmonic-generation (SHG) crystal; and the pulse relative delay must be scanned while maintaining alignment. Alignment involves four sensitive degrees of freedom and has great potential for error. Worse, bandwidth considerations require a very thin SHG crystal, which severely limits device sensitivity.Frequency-Resolved Optical Gating (FROG), which yields the full time-dependent pulse intensity and phase, requires adding a spectrometer to an autocorrelator apparatus, further complicating an already complicated apparatus. And FROG is the simplest proven intensity-and-phase measurement device. As a result, we have developed a remarkably simple,full-intensity-and-phase pulse-measurement device that 1) uses no spectrometer, 2) uses no beam-splitter or delay line, 3) avoids the thin crystal and instead uses a more convenient, thick SHG crystal, 4) is considerably more sensitive, 5) involves no sensitive alignment parameters,6) can measure a single pulse, and 7) comprises only a few simple optical components. It yields traces identical to those of SHG FROG, and hence yields the full time-dependent pulse intensity and phase. This device incorporates two key innovations: 1) a Fresnel biprism (a prism with a 170 apex angle), which replaces the beam splitter and delay line, and 2) a thicknonlinear crystal, whose output light is angularly resolved, yielding spectral resolution (as well as improved sensitivity and the usual time-gating), and which replaces the thin crystal and spectrometer.

超短激光脉冲的测量仍然是一项艰巨的任务。 自相关器，几十年来的首选设备，是复杂的，包括许多组件。 脉冲必须被分成两个;然后，这两个脉冲必须在仔细对准的二次谐波产生（SHG）晶体中在空间和时间上重叠;并且必须在保持对准的同时扫描脉冲相对延迟。 对准涉及四个敏感的自由度，并且具有很大的误差可能性。 更糟糕的是，带宽的考虑需要非常薄的SHG晶体，这严重限制了器件的灵敏度。频率分辨光学选通（FROG）产生完全依赖于时间的脉冲强度和相位，需要在自相关器装置上增加光谱仪，使本已复杂的装置进一步复杂化。 FROG是最简单的强度和相位测量设备。 因此，我们已经开发了一种非常简单的全强度和相位脉冲测量装置，其1）不使用分光计，2）不使用分束器或延迟线，3）避免薄晶体，而是使用更方便的厚SHG晶体，4）相当灵敏，5）不涉及灵敏的对准参数，6）可以测量单个脉冲，以及7）仅包括几个简单的光学部件。 它产生与SHG FROG相同的迹线，因此产生完全依赖于时间的脉冲强度和相位。 该设备包含两个关键创新：1）菲涅耳双棱镜（顶角为170 °的棱镜），取代了分束器和延迟线，2）厚非线性晶体，其输出光被角度分辨，产生光谱分辨率（以及改进的灵敏度和通常的时间选通），并取代了薄晶体和光谱仪。