5 results about "Reciprocal lattice" patented technology

A reciprocal lattice image, which represents a lattice point group of a reciprocal lattice, is generated by performing a two-dimensional Fourier transform on a target image. In addition, a target lattice, in which an arrangement of the lattice point group approximates an arrangement of a target focal spot group, is estimated with reference to a lattice vector of the reciprocal lattice. Then, lattice coordinates of a lattice point, which is closest to a target focal spot, of the target lattice are assigned to each corresponding target focal spot, thereby pairing the target focal spot with a reference focal spot.

Systems, methods, and media for calibrating a scanning electron microscope (SEM). The system includes a processor and a memory. The memory stores instructions that, when executed by the processor, configure the system to perform operations. An electron microscope image of a periodic structure is generated by the SEM. A Fourier transform of the electron microscope image is computed to generate a spectrum. Reciprocal lattice vectors are computed based on a known periodicity of the periodic structure. A pixel mask is generated based on the reciprocal lattice vectors and applied to filter the spectrum. A quality metric is generated based on an aggregate magnitude of the filtered spectrum and a magnitude of a zero-frequency component of the filtered spectrum. A pixel scaling parameter, focus parameter, and / or stigmation parameter of the SEM are determined based on the quality metric.

This invention provides a multi-channel three-dimensional quasi-phase matching method and apparatus. The method includes: focusing fundamental frequency light through a microscope objective to obtain fundamental frequency light with a modified focusing state; incident the modified fundamental frequency light onto a nonlinear photonic crystal via normal incidence, and obtaining an outgoing second harmonic through the nonlinear photonic crystal; and finally, outputting multi-channel frequency-doubled light waves based on the outgoing second harmonic. This invention focuses fundamental frequency light onto a nonlinear photonic crystal via a microscope objective, changing the direction range of the incident fundamental frequency wave vector simply by altering the numerical aperture of the focusing objective. Combined with the spatial reciprocal lattice vector combination of the three-dimensional nonlinear photonic crystal, the quasi-phase matching condition is satisfied, achieving variable multi-channel frequency doubling. This invention achieves controllable multi-channel second harmonic generation without structural changes.

A method of operating a spectrometer includes positioning a crystal analyzer such that a first reciprocal lattice vector corresponding to a first crystal surface of the crystal analyzer is coplanar with a source axis and a detector axis; and performing a first scan by changing a first angle between the source axis and the first crystal plane and changing a second angle between the detector axis and the first crystal plane such that the first angle is substantially equal to the second angle; rotating the crystal analyzer such that a second reciprocal lattice vector corresponding to a second crystal surface of the crystal analyzer is coplanar with the source axis and the detector axis; and performing a second scan by changing the first angle and changing the second angle such that the first angle is substantially equal to the second angle.

The light emitting device of the present disclosure is an S-iPM laser with M-point oscillation of a phase modulation layer. In-plane wave number vectors of 4 directions each including a wave number spread corresponding to an angle spread of emergent light from the light emitting device are formed on a reciprocal lattice space of the phase modulation layer. A magnitude of at least one of the in-plane wave number vectors is less than 2π / λ. A prescribed phase distribution included in the phase modulation layer includes an element for condensing the emergent light.