Complete single-shot measurement of arbitrary nanosecond laser pulses in time

Abstract

For essentially all applications, laser pulses must avoid variations in their intensity and phase within a pulse and from pulse to pulse. Currently available devices work very well for both long (>10ns) and short (<100ps) pulses. But intermediate (~ns) pulses remain difficult to measure and, not surprisingly, are the least stable. Here we describe a simple, elegant, complete, all-optical, single-shot device that measures ~ns pulses and that does not require a reference pulse or assumptions about the pulse shape. It simultaneously achieves a very high spectral resolution of <1pm and a very large delay range of ~10ns (several meters of light travel). It accomplishes both goals using high-efficiency, high-finesse etalons: one to generate high angular dispersion for a high-resolution spectrometer, and another to tilt the pulse front by ~89.9° without distorting it in time. Using this device, we completely measure microchip and fiber-amplifier pulses.

Using Pulse-Front Tilt to Measure Laser Pulses Less Than 100 Picoseconds in Duration

“…However, they measured just the intensity profiles of laser pulses, without any phase information. Bowlan et al generated significant angular dispersion using etalons and got the results with temporal range from 175 ps to 3 ns [12] . However, a highenergy laser should be required to obtain the autocorrelation results, due to the intrinsic high loss of an etalon(over 10 µJ).…”

100% reliable algorithm for second-harmonic-generation frequency-resolved optical gating

“…Arguably, the most practical, reliable, and well-developed method is frequency-resolved optical gating (FROG), whose variations generate various types of spectrograms of the pulse, depending on the nonlinear-optical process involved [1]. FROG routinely measures pulses from attoseconds to nanoseconds in length [9,10], from the XUV to the IR in wavelength [11,12], and from simple to extremely complex in shape [13,14]. Also, FROG's two-dimensional traces significantly overdetermine the pulse, so that discrepancies between measured and retrieved traces indicate (in)stability of a pulse train [5,7].…”

Complete temporal characterisation of highly chirped ultrabroadband optical pulses

“…Although FROG has been used to measure nanosecond duration optical pulses [31] and more recently been applied to the measurement of highly chirped pulses [32], it is not ideally suited to the task. For extremely large stretch factors, employing a single-shot version becomes problematic, whereas a scanning version becomes impractical and unstable.…”