Search results
Results from the WOW.Com Content Network
This allows quasi-phase-matching to exist at different domain widths . From this equation it is apparent, however, that as the quasi-phase match order increases, the efficiency decreases by . For example, for 3rd order quasi-phase matching only a third of the crystal is effectively used for the generation of signal frequency, as a consequence ...
The structure is designed to achieve quasi-phase-matching (QPM) in the material. Periodically poled crystals are frequently used as nonlinear optical materials. They are more efficient at second-harmonic generation than crystals of the same material without periodic structure.
This would lead to beam walk-off, which limits the nonlinear optical conversion efficiency. Two other methods of phase matching avoid beam walk-off by forcing all frequencies to propagate at a 90° with respect to the optical axis of the crystal. These methods are called temperature tuning and quasi-phase-matching.
Nonlinear photonic crystals are usually used as quasi-phase-matching materials. They can be one-dimensional, [1] two-dimensional [2] or three-dimensional. [3]
The more precise mathematical definition is that there is never translational symmetry in more than n – 1 linearly independent directions, where n is the dimension of the space filled, e.g., the three-dimensional tiling displayed in a quasicrystal may have translational symmetry in two directions.
Quantitative phase contrast microscopy, a group of microscopy methods; Quasi-phase-matching, a technique in nonlinear optics; Queen's Police Medal, awarded to UK/Commonwealth police officers; Questions of Procedure for Ministers, the confidential predecessor of the Ministerial Code (United Kingdom)
The interactions in PPKTP are based upon quasi-phase-matching, achieved by periodic poling of the crystal, whereby a structure of regularly spaced ferroelectric domains with alternating orientations are created in the material. PPKTP is commonly used for Type 1 & 2 frequency conversions for pump wavelengths of 730–3500 nm.
Schematic of SPDC process. Note that conservation laws are with respect to energy and momentum inside the crystal.. Spontaneous parametric down-conversion (also known as SPDC, parametric fluorescence or parametric scattering) is a nonlinear instant optical process that converts one photon of higher energy (namely, a pump photon) into a pair of photons (namely, a signal photon, and an idler ...