@mastersthesis {10000,
	title = {High resolution and high efficiency time-to-space conversion of ultrafast signals},
	year = {2014},
	type = {PhD thesis},
	abstract = {Ultrashort optical pulses are widely and increasingly used in many diverse fields of\&nbsp;science and technology. By providing high temporal resolution they enable\&nbsp;investigation and measurement of fundamental physical, chemical and biological\&nbsp;phenomena that occur on picosecond time scales or shorter. In addition ultrashort\&nbsp;pulses are an essential enabling tool for high speed optical communications and data\&nbsp;processing technologies, as well as in advanced manufacturing and photomedicine\&nbsp;applications. In all of these areas precise measurement and control of ultrashort\&nbsp;optical pulses is vital - advances in ever shorter pulse generation must be\&nbsp;accompanied by new methods to characterise and manipulate them.
This thesis presents work on the ongoing development of an ultrashort pulse\&nbsp;measurement and manipulation technique known as time-to-space conversion. Time-to-space conversion uses sum-frequency generation between spectrally resolved\&nbsp;ultrashort pulses to transfer information from the time domain to the space domain; in\&nbsp;other words to create the real-time spatial image of an ultrashort pulse. Mapping the\&nbsp;pulse temporal intensity envelope and phase onto a quasi-static spatial image allows\&nbsp;high resolution measurement of these quantities, overcoming the difficulty of\&nbsp;optoelectronic detection of ultrashort pulses directly in the time domain. Furthermore,\&nbsp;the spectrally resolved nature of time-to-space conversion results in a large time\&nbsp;window of operation. This enables a series of ultrashort pulses to be simultaneously\&nbsp;transferred to spatially separated locations via interaction with a single reference\&nbsp;pulse, thereby performing an all-optical demultiplexing operation.
The two main developments introduced in this thesis are: a) greater feasibility of time-to-space conversion for all-optical demultiplexing of a high speed optical\&nbsp;communications channel by demonstrating the technique in a planar nonlinear\&nbsp;waveguide and b) the demonstration of full-field characterisation of ultrashort pulses\&nbsp;by using interferometric detection after the time-to-space conversion. The practicality\&nbsp;of time-to-space conversion for all-optical demultiplexing depends on minimising its\&nbsp;optical power consumption. This can be achieved by implementation of the\&nbsp;conversion process in the guided-wave regime, as opposed to the free-space regime in\&nbsp;which it has previously been demonstrated. The first three papers presented in this\&nbsp;thesis describe the preliminary steps towards this goal, namely the demonstration of\&nbsp;non wavelength-degenerate and background-free collinearly phase-matched time-tospace\&nbsp;conversion and the demonstration of time-to-space conversion in a planar\&nbsp;nonlinear waveguide. Full-field characterisation of ultrashort pulses by time-to-space\&nbsp;conversion is enabled by the quasi-monochromaticity of the output sum-frequency\&nbsp;signal, a feature which follows from the unique geometry of the oppositely dispersed\&nbsp;waves of the pulse to be measured and the reference pulse. The quasi-monochromatic\&nbsp;converted signal can be mixed with a narrow linewidth local oscillator for\&nbsp;interferometric measurement of the ultrashort pulse field amplitude and phase. The\&nbsp;final two papers included here describe the first time demonstration of full-field\&nbsp;measurement of bandwidth-limited and chirped pulses by time-to-space conversion\&nbsp;and of single-shot coherent detection of a phase modulated ultrashort pulse train.
Taken together, the work presented in this thesis has achieved an increase in the utility\&nbsp;of time-to-space conversion as an ultrashort optical pulse measurement and\&nbsp;manipulation technique, with potential applications in optical communications and\&nbsp;data processing and in the field of ultrashort pulse measurement.},
	url = {http://hufind.huji.ac.il/Record/HUJ001973652},
	author = {Dror Shayovitz}
}
