Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase retrieval via regularization in self-diffraction based spectral
  interferometry   A novel variant of spectral phase interferometry for direct electric-field
reconstruction (SPIDER) is introduced and experimentally demonstrated. Other
than most previously demonstrated variants of SPIDER, our method is based on a
third-order nonlinear optical effect, namely self-diffraction, rather than the
second-order effect of sum-frequency generation. On one hand, self-diffraction
(SD) substantially simplifies phase-matching capabilities for multi-octave
spectra that cannot be hosted by second-order processes, given manufacturing
limitations of crystal lengths in the few-micrometer range. On the other hand,
however, SD SPIDER imposes an additional constraint as it effectively measures
the spectral phase of a self-convolved spectrum rather than immediately
measuring the fundamental phase. Reconstruction of the latter from the measured
phase and the spectral amplitude of the fundamental turns out to be an
ill-posed problem, which we address by a regularization approach. We discuss
the numerical implementation in detail and apply it to measured data from a
Ti:sapphire amplifier system. Our experimental demonstration used 40-fs pulses
and a 500 $\mu$m thick BaF${}_2$ crystal to show that the SD SPIDER signal is
sufficiently strong to be separable from stray light. Extrapolating these
measurements to the thinnest conceivable nonlinear media, we predict that
bandwidths well above two optical octaves can be measured by a suitably adapted
SD SPIDER apparatus, enabling the direct characterization of pulses down to
single-femtosecond pulse durations. Such characteristics appear out of range
for any currently established pulse measurement technique.

1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph