Measuring the electric field of picosecond to nanosecond pulses with high spectral resolution and high temporal resolution

The subject matter of this thesis is in the field of ultrashort pulse measurement. The succeeding chapters detail four new techniques for measuring the electric field of complex pulses with high temporal resolution and high spectral resolution.;First, we demonstrate an extremely simple frequency-resolved-optical gating (GRENOUILLE) device for measuring the intensity and phase of relatively long---ps---pulses. In order to achieve the required high spectral resolution and large temporal range, it uses a few-cm-thick second harmonic-generation crystal in the shape of a pentagon. This has the additional advantage of reducing the device's total number of components to as few as three simple easily aligned optics, making it the simplest device ever developed for complete pulse measurement. We report complete intensity-and-phase measurements of pulses up to 15ps long with a time-bandwidth product of 21.;Secondly, we introduce a variation of spectral interferometry (SI) using a virtually imaged phased array and grating spectrometer for measuring long complex ultrashort pulses up to 80 ps in length. To our knowledge this is the longest pulse every measured using Fourier transform SI (FTSI), and the first use of a VIPA/grating spectrometer for FTSI.;Next, we introduce a SI technique for measuring the complete intensity and phase of relatively long and very complex ultrashort pulses. Ordinarily, such a method would require a high-resolution spectrometer, but our method overcomes this need. It involves making multiple measurements using SI (in its SEA TADPOLE variation) at numerous delays, measuring many temporal pulselets within the pulse, and concatenating the resulting pulselets. Its spectral resolution is the inverse delay range---many times higher than that of the spectrometer used. The waveforms were measured with ∼40 fs temporal resolution over a temporal range of ∼3.5ns and had time-bandwidth products exceeding 65,000, which to our knowledge is the largest time-bandwidth product ever measured with ∼fs temporal resolution.;Finally, we demonstrate the first single-shot measurement technique that temporally interleaves hundreds of measurements with ∼125 fs temporal resolution. It is another variation of SI for measuring the complete intensity and phase of relatively long and complex ultrashort pulses in a single shot. Ordinarily, such a method would require a high-resolution spectrometer, but by temporally interleaving many delayed spectral measurements our method overcomes this need. It uses a grating to introduce a transverse time delay into the reference pulse by tilting the pulse front. The tilted reference pulse is used to gate the unknown pulse by interfering it at the image plane of an imaging spectrometer. Our simple proof-of-principle implementation resulted in an increase in the spectral resolution of the spectrometer used by a factor of 15. It provided ∼125 fs temporal resolution and a temporal range of 70 ps using a low-resolution spectrometer.