The imaging quality of an optical imaging system is interferometrically measured. A wavefront measurement has a first imaging scale .sub.1 in a first direction and a second imaging scale .sub.2 in a second, perpendicular direction. The second imaging scale differs from the first imaging scale by a scale ratio (.sub.1/.sub.2)1 (anamorphic imaging system). A first measurement structure (MS1) on a first structure carrier arranged on the object side of the imaging system has a two-dimensional mask structure suitable for shaping the coherence of measurement radiation. A second measurement structure (MS2) on a second structure carrier arranged on the image side of the imaging system has a diffraction grating. The first and second measurement structures are mutually adapted, taking account of the scale ratio so that an interference pattern arises upon imaging the first measurement structure onto the second measurement structure using the anamorphic imaging system.

A method and an apparatus for measuring a coherence of a light source of a holographic display through steps of: photographing an interference pattern generated by light output from the light source; obtaining an interference pattern feature information with respect to the interference pattern from an interference pattern image of the interference pattern; and measuring the coherence of the light source based on the interference pattern feature information, are provided.

A wavefront sensor includes a mask and a sensor utilized to capture a diffraction pattern generated by light incident to the mask. A reference image is captured in response to a plane wavefront incident on the mask, and another measurement image is captured in response to a distorted wavefront incident on the mask. The distorted wavefront is reconstructed based on differences between the reference image and the measurement image.

According to a first aspect, there is provided a method of holographic wavefront sensing, the method including: receiving a light beam, which has a wavefront to be analyzed, on a transparent, flat substrate, which is provided with a lattice of opaque dots, wherein the substrate is arranged above an image sensor; detecting by the image sensor an interference pattern formed by diffracted light, being scattered by the opaque dots, and undiffracted light of the light beam received by the image sensor; processing the detected interference pattern to digitally reconstruct a representation of a displaced lattice of opaque dots, which would form the interference pattern on the image sensor upon receiving the light with a known wavefront; and comparing the representation of the displaced lattice to a known representation of the lattice of opaque dots on the substrate to determine a representation of the wavefront form of the received light beam.

A wavefront sensor system suitable for integration into an integrated circuit light detector may provide for wave angle sensors having varying functional relationships between the wave angle and signal to provide improved dynamic range. These wave angle sensors may be combined with integrated circuit phase angle sensors for a more complete analysis of the waveform.

Systems and methods disclosed herein provide for gas imaging. A gas imaging system comprises a lenslet array configured to receive thermal radiation from a scene and transmit a plurality of substantially identical sub-images of the thermal radiation; a birefringent polarization interferometer configured to generate an optical path difference for each ray of the plurality of sub-images based on a respective position of each ray entering the BPI, the optical path differences combining to form an interference fringe pattern; and an infrared focal plane array configured to capture a thermal image of the plurality of sub-images modulated by the interference fringe pattern due to the optical path differences through the BPI. The captured thermal image may represent a plurality of interferogram sample points of the thermal radiation from the scene, and may be used to construct a plurality of hyperspectral images of the thermal radiation from the scene.

A wavefront measuring device and method obtain wavefront information of an optical system. The method including: irradiating the optical system with a light beam; allowing the light beam passed via the optical system to come into a diffraction grating having periodicity in a first direction; and obtaining the wavefront information based on an interference fringe formed by light beams generated from the diffraction grating. The diffraction grating including: first portions which allow light to pass therethrough; and second portions which shield light, each of the second portions being provided between two of the first portions. A ratio between a width of one of the first portions in the first direction and a width of one of the second portions in the first direction is changed in the first direction, the one of the first portions and the one of the second portions being adjacent to each other.

A shearing interferometer includes first and second shearing plates disposed opposite to each other. The first shearing plate includes a first front surface and a first back surface, and splits an input beam input to the first front surface into first and second beams reflected at the first front and back surfaces, respectively. The second shearing plate includes a second front surface and a second back surface. The second shearing plate splits the first beam into third and fourth beams reflected at the second front and back surfaces, respectively, and splits the second beam into fifth and sixth beams reflected at the second front and back surfaces, respectively. Each of the first and second shearing plates has a thickness which limits a phase delay between the fourth beam and the fifth beam to a degree determined to allow interference to occur between the fourth beam and the fifth beam.

A method for evaluating the quality of the measurement of an optical wavefront, said measurement being obtained by means of a wavefront analyzer by direct measurement, the method comprising: the acquisition (10) of an optoelectronic signal for the measurement of the wavefront by means of a wavefront sensor, said sensor comprising a two-dimensional detector; the determination (11) on the basis of said optoelectronic signal of at least one parameter characteristic of a parasitic component of the optoelectronic signal; the evaluation (12) of a quality factor of the measurement of the wavefront as a function of said at least one parameter characteristic of the parasitic component of the signal; the display (13) to a user of a level of quality of the measurement as a function of said quality factor.

A wavefront sensor system suitable for integration into an integrated circuit light detector may provide for wave angle sensors having varying functional relationships between the wave angle and signal to provide improved dynamic range. These wave angle sensors may be combined with integrated circuit phase angle sensors for a more complete analysis of the waveform.