Search results for "Physics::Optics"
showing 10 items of 1958 documents
Generation and detection of optical rogue-wave-like fluctuations in fiber Raman amplifiers
2009
Rogue wave-like statistics is reported in a fiber Raman amplifier. The pump-signal noise transfer leads to the development of large peak-power fluctuations following a powerlaw probability distribution. Discrimination of the rarest events is demonstrated.
Polychromatic Cherenkov radiation and supercontinuum in tapered optical fibers
2012
We numerically demonstrate that bright solitons in tapered optical fibers can emit polychromatic Cherenkov radiation providing they remain spectrally close to the zero dispersion wavelength during propagation along the fiber. The prime role in this phenomenon is played by the soliton self-frequency shift driving efficiency of the radiation and tuning of its frequency. Depending on tapering and input pulse power, the radiation is emitted either as a train of pulses at different frequencies or as a single temporally broad and strongly chirped pulse.
Accurate measurement of Poisson ratio in optical fibers based on forward-stimulated Brillouin scattering
2021
The interaction between light and sound in optical fibers is a phenomenon that researchers have been investigated for many decades. Among all the opto-acoustic effects that occurs in optical fibers, forward-stimulated Brillouin scattering (FSBS) has become of great interest as sensing mechanism due to the dependence of the excited acoustic resonances on both internal parameters [1] , [2] and surroundings [3] of the optical fiber. The vibrational modes behind FSBS are transverse acoustic resonances, in particular, the radial modes R 0m and the torsional-radial modes TR 2m . Most of the experiments reported based on FSBS exploit the properties of either the radial or the torsional-radial mode…
Observation of Modulational Instability induced by a dynamical Bragg grating in an optical fiber
2001
We present a detailed experimental study on Bragg Modulational Instability in a highly birefringent fiber. The originality of our scheme is that the index modulation is obtained through cross phase modulation with a beating wave.
OPCPA using beams shaped by diffractive optical elements
2011
Optical parametric chirped pulse amplification (OPCPA) is becoming a widely accepted technique for the generation of high energy ultrashort laser pulses. Flat-top spatial profile pump beams can improve the efficiency of OPCPA, however such beams can be energetically costly to generate and are difficult to implement for low pump energy systems. An elegant and efficient solution to the generation of flat-top spatial profiles is the use of a diffractive optical element (DOE), however these devices distort the geometric phase of the pulses, possibly making them unsuitable for phase coherent interactions such as OPCPA.
Diffractive optics for high-resolution low-coherence digital holography
2010
We study the properties of the recording of off-axis holograms when a 10 fs pulsed laser is used as illumination source. A proper optical design involving one diffractive lens outside a Michelson interferometer enables the recording of full-field off-axis holograms with high resolution and optical sectioning. We demonstrate our approach with some experimental results that show optical sectioning with a maximum resolution of 3.5 µm. We note that the axial resolution of the technique is reduced up to 9 µm when the object beam travels through a few millimeters of glass due to the pulse broadening along dispersive media.
Diffractive pulse-front tilt for low-coherence digital holography
2010
We use a diffractive lens to generate the proper pulse-front-tilt to record full-field off-axis holograms with a 10fs laser source. We experimentally demonstrate optical sectioning of three-dimensional samples with a resolution of about 5 microns.
Rogue wave statistics from a noise-like-pulse laser
2014
We report on experimental conditions in a fiber ring laser where noise-like pulse emission fulfills the rogue wave criteria. We highlight the role of dispersion, and use the dispersive Fourier-transform method to study spectral fluctuations.
Dissipative rogue waves out of fiber lasers
2012
We study rogue waves in dissipative systems such as unidirectional fiber laser. We have found that the probability of producing extreme pulses in this setup is higher than in any other system considered so far.
Experimental verification of a self-consistent calculation for continuous frequency-tune with a 400 GHz band second harmonic gyro-BWO
2013
A self-consistent code is introduced to develop a continuous frequency tunable gyro-BWO. A cavity is designed with TE8,5 mode for 400 GHz band second harmonic oscillation. The experimental verification has been carried out and 2 GHz tunability is observed with output powers of higher than 40 W.