SBIR Phase I: Simple Device for Measuring Nanosecond Laser Pulses

该小型企业创新研究(SBIR)第一阶段项目计划开发一种简单、单次、廉价且完整的激光脉冲测量设备，可测量~100ps至~10 ns的脉冲。虽然长脉冲(10 Ns)很容易测量，并且最近发展的技术完全测量超短脉冲(10ps)、中等长度~1 ns，但脉冲仍然只是部分和大致可测量的，因此，这种脉冲通常保持复杂和不稳定。这是不幸的，因为大多数商用脉冲激光器在这个中间范围内发射脉冲。该测量装置扩展了频率分辨光学门控(FROG)，这是一种非常成功的测量超短脉冲完整强度和相位随时间变化的技术，其操作方法是测量脉冲的谱图。将FROG扩展到更长的脉冲的主要挑战是在单次激发上产生许多纳秒的延迟范围--目前总体上这是一个尚未解决的问题。所提出的创新通过将输入脉冲显著倾斜~89.9°来解决这个问题，而不会及时使其失真。因此，一束约1厘米宽的光束的一侧比另一侧领先一米以上。提出的ns蛙甚至可以测量非常复杂的脉冲，其成本将是目前仅用于部分测量此类脉冲的高带宽示波器的十分之一左右。该项目的更广泛的影响/商业潜力将扩展到大多数脉冲激光器，从Q开关和增益开关固体激光器到发射~ns脉冲并有许多应用的光纤激光器。所有这些应用都将从这款设备中受益。首先，~ns-激光用户现在将有一个设备来测试他们的激光？S的性能，而且它将是简单，易于使用，单次拍摄，并且相对便宜。这对于尝试相干地组合来自多个光纤激光器的脉冲将是必不可少的，这通常被认为是高功率光纤激光器发展的下一个重要步骤。努力发射非常干净的~ns脉冲的注入种子型Q开关和增益开关激光器也需要这样一种方法来确认性能。最后，激光工程师一般将能够更好地提高~ns激光脉冲的质量，从而极大地有利于所有~ns脉冲激光的实验和应用。如果完全的超短脉冲测量技术被引入后，超快激光取得的惊人进步是任何迹象的话，那么这种廉价而简单的测量ns脉冲的设备应该会在产生更稳定的~ns脉冲方面产生巨大的不同，从而在使用这种激光的许多领域，从焊接到外科手术到材料加工到距离测量到遥感。

This Small Business Innovation Research (SBIR) Phase I project proposes to develop a simple, single-shot, inexpensive, and complete laser-pulse measurement device for ~100ps to ~10ns pulses. While long (10ns) pulses are easily measured, and recently developed techniques completely measure ultra-short pulses (10ps), intermediate-length ~1ns, pulses remain only partially and roughly measurable, and, consequently, such pulses generally remain complex and unstable. This is unfortunate because most commercial pulsed lasers emit pulses in this intermediate range. The proposed measurement device extends Frequency-Resolved Optical Gating (FROG), a very successful technique for measuring the complete intensity and phase versus time of ultra-short pulses, which operates by measuring the pulse's spectrogram. The main challenge in extending FROG to much longer pulses is the generation of a many-ns delay range on a single shot - currently an unsolved problem in general. The proposed innovation solves it by tilting the input pulse by a remarkable ~89.9° without distorting it in time. As a result, one side of a ~1cm-wide beam precedes the other by over a meter. The proposed ns FROG can measure even very complex pulses and will cost about one tenth as much as the high bandwidth oscilloscopes currently used to only partially measure such pulses. The broader impact/commercial potential of this project will extend to most pulsed lasers, from Q-switched and gain-switched solid-state lasers to fiber lasers, which emit ~ns pulses and have many applications. All such applications will benefit from this device. First, ~ns-laser users will now have a device to test their laser?s performance, and it will be simple, easy to use, single-shot, and relatively inexpensive. It will be essential in attempts to coherently combine pulses from multiple fiber lasers, generally regarded as the next important step in high-power fiber-laser development. Injection-seeded Qswitched and gain-switched lasers, which endeavor to emit very clean ~ns pulses, are also in need of such a method for performance confirmation. Finally, laser engineers in general will be better able to improve the quality of ~ns-laser pulses, greatly benefitting all ~ns-pulsed-laser experiments and applications. If the spectacular progress in ultrafast lasers that occurred after complete ultra-short-pulse-measurement technology was introduced is any indication, such an inexpensive and simple device for measuring ns pulses should make a huge difference in the generation of ever more stable ~ns pulses and consequently in the many fields that use such lasers, from welding to surgery to material processing to distance measurements to remote sensing.