S. E. Putilin

The transmission of 45 bits of information by a pair of interfering femtosecond pulses with superwide spectra

It has been experimentally demonstrated that 45 bits of information can be optically recorded and transmitted by one quasi-discrete spectral supercontinuum, formed when two femtosecond pulses with superwide spectra interfere with a time delay between them less than the width of each pulse.

Ultrafast information transfer through optical fiber by means of quasidiscrete spectral supercontinuums

Abstract. Information transfer through single-mode optical fiber by means of quasidiscrete spectral supercontinuums in the 1300- to 1620-nm wavelength range has been demonstrated. Using 16 spectral lines in each supercontinuum at the repetition rate of 70 MHz allows for a 1.1-Gb/s information transfer rate to be achieved. It has been shown that the proposed information transfer method can achieve a 0.8-Tb/s information transfer rate using existing telecommunications equipment.

Particularities of femtosecond spectral supercontinuum generation in anisotropic crystal media with quadratic nonlinearity

Results of supercontinuum generation experiments in case of excitation by optical pulses with central wavelength 828 nm, duration 40-50 fs, energy up to 1,0-1,5 mJ are presented. Supercontinuum radiation was detected in crystal DKDP and other crystals with χ(2)-nonlinearity at range from 400 nm to 1450 nm, as well as up to 2300 nm, where radiation within blue range 400-480 nm and IR-range 900-2300 nm was caused by parametric processes. Obtained radiation was analog of microstructured fibers supercontinuum radiation in the width of output spectrum.

Formation of a Sequence of Femtosecond Optical Pulses with a Terahertz Repetition Rate

We have shown experimentally that, upon interference of two frequency-modulated femtosecond pulses, a sequence of ultrashort subpulses is formed to which a quasi-discrete spectral continuum corresponds in the spectral range. We have shown that it is possible to control the duration and repetition rate of subpulses in the sequence by varying the delay between the interfering pulses.

An Investigation of the Transmission of Iron-Doped Zinc Selenide in the Terahertz-Frequency Range

We present the results of our experimental investigation of the transmission of plates of zinc-selenide crystal doped with iron at a level of 0.23 mass % in the terahertz-frequency range and compare them with the transmission of undoped samples. We show that the presence of iron impurities in a zinc-selenide sample makes the medium more transparent in the frequency range from 0.35 to 0.5 THz. The transmission of a doped sample in this range increases to 20% compared to pure ZnSe. This result can be used in the future to create efficient devices for controlling terahertz radiation.

Spatial-temporal dynamics of the terahertz field generated by femtosecond filament

We present the study on spatial distribution of the maximum of terahertz field amplitude in time domain when generated by a femtosecond filament. It is shown that as a result of the propagation of the terahertz field forms a spherical wave front, on the edge of which the maximum of amplitude has a temporary delay in contrary to its central part.

Time-Resolved Inline Digital Holography for Investigation of Noncollinear Pump Pulse-Induced Phase Variation

Time-resolved inline digital holography technique for investigation of optical nonlinear interaction of high-energy pump with probe pulse in transparent samples is presented. The observed inline hologram in the Fresnel diffraction zone depends on variation of refractive index and allows one to analyze some properties of the nonlinear media.

Direct measurement of the parameters of a femtosecond pulse train with a THz repetition rate generated by the interference of two phase-modulated femtosecond pulses

A femtosecond pulse train with THz repetition rate generated by the interference of two phase-modulated pulses has been recorded experimentally. Pulse repetition rates and their duration have been measured. It has been shown that at the 50-fs time delay between phase-modulated pulses the repetition rate is 3.1 THz with a pulse width of 200 fs, while at the 120-fs time delay the repetition rate is 7.1 THz with a pulse width of 67 fs.