Numerical Study of Spectron Shaping Process:
, H. Toneyan
, A. Kutuzyan
, M. Sukiasyan
, D. Gulqanyan
, K. Apresyan
, and L. Mouradian
Yerevan State University, Yerevan, Armenia
Synchrotron Research Institute CANDLE, Yerevan, Armenia
Received December 14, 2017
Abstract⎯The phase peculiarities of spectron are investigated from the point of view of the
dispersive Fourier transformation. For different original pulses with the various initial spectral phases,
the numerical analysis had shown that by the forming the spectron, the transfer of information from
the spectral region to the time domain could take place not only for the amplitude but also for the
phase of the field of radiation.
Keywords: spectron, spectral phase, dispersion, amplitude and phase modulation
A pulse, which temporal envelope of intensity repeats the spectral profile is called a spectron. The
spectron is formed at the propagation of the pulse in a long enough dispersive medium [1, 2] on the
temporal analogy with the diffraction in the far-field zone (the Fraunhofer diffraction). The forming of the
spectron was investigated within the framework of the dispersive Fourier transformation (DFT) method
[2–5], or the Fourier transform in real time [6–8]. The DFT method uses a dispersion element and a
single-pixel photodiode for spectral measurements in the real-time, eliminating the restraints of the speed
performance of traditional spectrometers . This method has many applications such as the real-time
spectroscopy, the fast optical imaging, laser scanning, and the like. Although the process of the spectron
forming is well known, the phase features of the spectron have not been studied in detail. Investigations
of the phase features of the spectron are of interest, in particular, for determining the spectral phase and
the subsequent complete characterization of femtosecond pulses. Information on the spectral phase along
with the spectral amplitude (spectrum) enables to reconstruct the complex radiation field, that is, the time
intensity and phase by the spectral interferometry [9–12] and the spectral shift interferometry [9, 13].
As an alternative to technically complex methods [9–13], the present paper enables one to propose the
determination of the phase of the spectron based on the generation of the summary frequency . The
aim of the present work is the study of the phase features of the spectron, in particular, the search for
conditions under which the temporal phase of the spectron repeats the spectral phase.
ISSN 1068–3372, Journal of Contemporary Physics (Armenian Academy of Sciences), 2018, Vol. 53, No. 2, pp. 129–135. © Allerton Press, Inc., 2018.
Original Russian Text © N. Karapetyan, H. Toneyan, A. Kutuzyan, M. Sukiasyan, V. Avetisyan, D. Gulqanyan, K. Apresyan, L. Mouradian, 2018, published in
Izvestiya Natsional'noi Akademii Nauk Armenii, Fizika, 2018, Vol. 53, No. 2, pp. 173–180.