Results 211 to 220 of about 491,257 (266)
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Phase-modulation scatterometry
Applied Optics, 2002Phase-modulation scatterometry is a metrology technique for determining, by means of a phase modulator as a key device, the parameters of gratings. The main source of error to be dealt with are the fluctuations of the phase-modulation amplitude. The grating zeroth-order reflectance modulated by the phase modulator is converted into a signal by the ...
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Modulated cross-phase-modulation spectra
OSA Annual Meeting, 1993When a weak probe and a strong pump pulses propagate together in a material, coupled interactions occur through the third order nonlinearity. This process leads to the self-phase-modulation (SPM) and cross-phase-modulation (XPM). The spectral shift of XPM can be controlled by adjusting the time delay between the pump and probe pulses.1 When the pump ...
Q. Z. Wang +4 more
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Modulating ionization through phase control
Physical Review A, 1992We present a theory of modulating ionization by controlling the phases of incident laser fields. Specific calculations have been performed for the Na atom using the density-matrix equations. Significant modulation of the ion signal can be obtained by choosing the appropriate combinations of laser intensities and frequencies, in resonant as well as ...
T. NAKAJIMA +3 more
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Organic polymer phase modulator
Optical Society of America Annual Meeting, 1991There has been an increasing interest in using organic polymers to implement optical waveguide devices. Organic polymers have low intrinsic losses, and devices built with these materials can easily be fabricated using standard VLSI technology. However, most organic polymers have a glass transition temperature (T g ) of less than 100°C.
Yuen, S.F. +2 more
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Photoelastic modulator: polarization modulation and phase modulation
Journal of Optics, 1995Photoelastic modulators are studied here as both birefringence (or polarization) and phase modulators. In the first part of this work we have determined the influences of time dependent variations of index and thickness, for an ideal modulator where oscillation is supposed to be perfectly longitudinal.
D Yang, J C Canit, E Gaignebet
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Birefringence modulation in fiber-optic phase modulators
Optics Letters, 1994We report an unusually large birefringence modulation in fiber-optic phase modulators formed with cylindrical piezoelectric transducers when driven at a few hundred kilohertz. The magnitude of the birefringence modulation is a strong function of modulation frequency.
JEONG, HJ +3 more
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Note on self-phase modulation and cross-phase modulation
Optics Communications, 1995Abstract It is investigated to what extent self-phase modulation and cross-phase modulation operate when a single badly mode locked laser pulse travels in a nonlinear medium. We restrict our investigation of intensity induced phase effects to those that can be measured with stationary interference patterns.
B. Lesche, W. Margulis
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Review of Scientific Instruments, 1999
A new type of optical modulator is reported in which a phase grating is used to diffract a beam of light. Piezoelectric elements modulate the phase shift between adjacent portions of the grating, and hence control the diffraction efficiency. Efficiencies of up to about 17% have been observed, compared to the theoretical maximum of about 40% for ...
Mohammed S. Hasan, Martin Feldman
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A new type of optical modulator is reported in which a phase grating is used to diffract a beam of light. Piezoelectric elements modulate the phase shift between adjacent portions of the grating, and hence control the diffraction efficiency. Efficiencies of up to about 17% have been observed, compared to the theoretical maximum of about 40% for ...
Mohammed S. Hasan, Martin Feldman
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Modulation instability induced by cross-phase modulation
Physical Review Letters, 1987Modulation instability that leads to breakup of intense cw radiation into a train of ultrashort pulses during propagation in optical fibers occurs only in the presence of anomalous group-velocity dispersion. It is shown that a new kind of modulation instability can occur even in the normal-dispersion regime when two copropagating optical fields ...
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International Journal of Modern Physics B, 1993
General aspects of modulated magnetic phases are reviewed. The present understanding of the microscopic origin of such phases is discussed. A few examples of modulated magnetic phases are treated in detail. Temperature, pressure and magnetic-field-induced transitions of the modulated magnetic phases are reviewed.
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General aspects of modulated magnetic phases are reviewed. The present understanding of the microscopic origin of such phases is discussed. A few examples of modulated magnetic phases are treated in detail. Temperature, pressure and magnetic-field-induced transitions of the modulated magnetic phases are reviewed.
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