A three-dimensional imaging system including a light source configured to emit a beam of spatially incoherent light, having a given central length, configured to illuminate a biological sample being transmitted; an optical imaging system including a microscope lens with a given object focal plane near which the sample is positioned; mechanisms for axially moving the microscope lens relative to the sample; a two-dimensional acquisition device including a plurality of elementary detectors arranged in a detection plane optically conjugate with the object focal plane and a processing unit. For each section of a biological object of the sample, a plurality of two-dimensional interferometric signals resulting from optical interference between the illumination beam and a beam scattered by an object field of the section are acquired and at least a first image is calculated from the plurality of two-dimensional interferometric signals.

A projection exposure tool for microlithography for imaging mask structures of an image-providing substrate onto a substrate to be structured includes a measuring apparatus configured to determine a relative position of measurement structures disposed on a surface of one of the substrates in relation to one another in at least one lateral direction with respect to the substrate surface and to thereby simultaneously measure a number of measurement structures disposed laterally offset in relation to one another.

The invention relates to a differential interferometer module adapted for measuring a direction of displacement between a reference mirror and a measurement mirror. In an embodiment the differential interferometer module is adapted for emitting three reference beams towards a first mirror and three measurement beams towards a second mirror for determining a displacement between said first and second mirror. In a preferred embodiment the same module is adapted for measuring a relative rotation around two perpendicular axes as well. The present invention further relates to a lithography system comprising such a interferometer module and a method for measuring such a displacement and rotations.

The invention relates to a lithography system comprising an optical column, a moveable target carrier for displacing a target such as a wafer, and a differential interferometer module, wherein the interferometer module is adapted for emitting three reference beams towards a first mirror and three measurement beams towards a second mirror for determining a displacement between said first and second mirror. In a preferred embodiment the same module is adapted for measuring a relative rotation around two perpendicular axes as well. The present invention further relates to an interferometer module and method for measuring such a displacement and rotations.

Provided is a high-resolution reflection tomographic imaging system and method. The high-resolution reflection tomographic imaging system of the present disclosure may include an objective lens, a tube lens, a camera, an illumination element configured to introduce temporally coherent and spatially incoherent light, and a semi-reflective surface element configured to split the light into a sample and a reference beam between the tube lens and the camera, such that a sample beam from the sample and the reference beam cause interference for tomographic imaging.

A parallelism measurement optical system module includes a polarization beam splitter, a mirror positioned on a first surface of the polarization beam splitter, a first quarter wave plate positioned on a second surface of the polarization beam splitter that is perpendicular to the first surface, and a second quarter wave plate positioned on a third surface of the polarization beam splitter that is perpendicular to the first surface and parallel to the second surface.

Systems, methods, and media for multiple beam optical coherence tomography are provided which, in some embodiments, include: a light source; a splitter that outputs a fraction of light to various waveguides; optical components that receive light from the waveguides and direct the light as beams that simultaneously impinge a sample at different lateral positions, and collect backscattered light from the lateral positons; another splitter that outputs a fraction of light to waveguides of a reference arm as reference light samples; a mixer that receives the backscattered light samples and the reference light samples, and combines each backscattered sample with a corresponding reference sample such that the mixer outputs fringes; and a detector that receives the fringes, and outputs OCT signals, each indicative of a structure of the sample at a respective lateral position.

A tomography apparatus based on a low coherence interferometer according to embodiments of the inventive concepts may include a plurality of wavelength-tunable lasers arranged in parallel, and an optical coupling unit interleaving pulses sequentially outputted from the plurality of wavelength-tunable lasers to increase a wavelength tuning speed of the wavelength-tunable lasers by N times where N corresponds to the number of the wavelength-tunable lasers. According to embodiments of the inventive concepts, the tomography apparatus may rapidly increase the wavelength tuning speed by applying the interleaving technique to obtain accurate tomographic image information, and thus the tomography apparatus can be widely used in medical fields (e.g., medical engineering and biomedical engineering), an aerospace field, a spectroscopy field, and a sensor field.

A system and method for the monitoring of ammonia in a fluid. The ammonia monitoring system includes an ammonia sensor that is configured to detect trace amounts of ammonia (NH.sub.3) in a fluid (i.e., gas or liquid) that is pumped through it in real time. The real time ammonia sensor includes an interferometer configured to track the amount of ammonia that is pumped into the real time ammonia sensor. The ammonia monitoring system, via the real time ammonia sensor, is further configured to detect ammonia levels in industrial poultry houses and provide electronic feedback to the building's ventilation control system.

Fizeau interferometers, in-flight metrology systems and methods of testing optical systems are described. Collimated or near collimated light is directed to interact with at least one diffractive focusing element of an optical system. The collimated or near collimated light is modified by the diffractive focusing element to form first diffracted light. The first diffracted light is directed to an image surface of the diffractive focusing element. A portion of light directed from the image surface is reflected by the diffractive focusing element back to the image surface as second diffracted light. The second diffracted light has a different diffraction order than the first diffracted light. The second diffracted light is detected to characterize the optical system.