An optical interferometer based on multi-mode interference (MMI) devices includes an input port, an output port, a first MMI device connected to the input port at an input face of the first MMI device, a second MMI device connected to the first output port at an output face of the second MMI device. In the optical interferometer, an output face of the first MMI device and an input face of the second MMI device are directly connected, the first MMI device includes a first and a second self-imaging points at an interface between the first MMI device and the second MMI device, and a propagation axis of the second MMI device is tilted with respect to a propagation axis of the first MMI device, causing a path length difference between an upper optical path via the first self-imaging point and a lower optical path via the second self-imaging point.

The present invention relates to an arrangement for the generation of images of optical sections of a three-dimensional (3D) volume in space such as an object, scene, or target, comprising: an illumination unit, an optical arrangement for the imaging of the object onto at least one spatially resolving detector, a scanning mechanism for scanning the entire object and a signal processing unit for the implementation of a method for digital reconstruction of a three-dimensional representation of the object from images of said object as obtained by said detector (which may be in a form of a hologram), wherein the optical arrangement includes a diffractive optical element (herein a phase pinhole), realized using a Spatial Light Modulator (SLM) configured to mimic an actual physical pinhole, while allowing the formation of a three-dimensional representation for a specific point of interest in said object, such that for each scanning position a single hologram or an image is recorded.

An optical interferometer based on multi-mode interference (MMI) devices includes an input port, an output port, a first MMI device connected to the input port at an input face of the first MMI device, a second MMI device connected to the first output port at an output face of the second MMI device. In the optical interferometer, an output face of the first MMI device and an input face of the second MMI device are directly connected, the first MMI device includes a first and a second self-imaging points at an interface between the first MMI device and the second MMI device, and a propagation axis of the second MMI device is tilted with respect to a propagation axis of the first MMI device, causing a path length difference between an upper optical path via the first self-imaging point and a lower optical path via the second self-imaging point.

A spectrometer and method for determining an emitted light spectrum. An input light signal is received and directed to an array of interferometers using waveguides. A plurality of self-interfering signals are detected from a first plurality of interferometers in the array of interferometers. The first plurality of interferometers has fewer interferometers than required to satisfy the Nyquist criterion for reconstructing the emitted light spectrum. The emitted light spectrum is reconstructed from the plurality of self-interfering signals using compressive sensing. The plurality of self-interfering signals can provide an interference pattern used to reconstruct the emitted light spectrum. A second plurality of interferometers may output a second plurality of self-interfering signals to reconstruct a low resolution spectrum of the input light signal satisfying the Nyquist criterion. Low resolution signal components can be detected from the low resolution spectrum and used to pre-process the interference pattern.

A spectrometer and method for determining an emitted light spectrum. An input light signal is received and directed to an array of interferometers using waveguides. A plurality of self-interfering signals are detected from a first plurality of interferometers in the array of interferometers. The first plurality of interferometers has fewer interferometers than required to satisfy the Nyquist criterion for reconstructing the emitted light spectrum. The emitted light spectrum is reconstructed from the plurality of self-interfering signals using compressive sensing. The plurality of self-interfering signals can provide an interference pattern used to reconstruct the emitted light spectrum. A second plurality of interferometers may output a second plurality of self-interfering signals to reconstruct a low resolution spectrum of the input light signal satisfying the Nyquist criterion. Low resolution signal components can be detected from the low resolution spectrum and used to pre-process the interference pattern.

A method, an interferometer, and a signal processing device, each for determining an input phase and/or an input amplitude of an input light field, are disclosed. Here, an input light field is divided into a first light field and a second light field by amplitude splitting. The first light field and the second light field are propagated such that the propagated second light field is defocused relative to the propagated first light field. The propagated first light field is superimposed on the propagated light field and caused to interfere.

A method, an interferometer, and a signal processing device, each for determining an input phase and/or an input amplitude of an input light field, are disclosed. Here, an input light field is divided into a first light field and a second light field by amplitude splitting. The first light field and the second light field are propagated such that the propagated second light field is defocused relative to the propagated first light field. The propagated first light field is superimposed on the propagated light field and caused to interfere.

The present invention provides a novel simple, portable, compact and inexpensive approach for interferometric optical thickness measurements that can be easily incorporated into an existing microscope (or other imaging systems) with existing cameras. According to the invention, the interferometric device provides a substantially stable, easy to align common path interferometric geometry, while eliminating a need for controllably changing the optical path of the beam. To this end, the inexpensive and easy to align interferometric device of the invention is configured such that it applies the principles of the interferometric measurements to a sample beam only, being a single input into the interferometric device.

An optical interferometer based on multi-mode interference (MMI) devices includes an input port, an output port, a first MMI device connected to the input port at an input face of the first MMI device, a second MMI device connected to the first output port at an output face of the second MMI device. In the optical interferometer, an output face of the first MMI device and an input face of the second MMI device are directly connected, the first MMI device includes a first and a second self-imaging points at an interface between the first MMI device and the second MMI device, and a propagation axis of the second MMI device is tilted with respect to a propagation axis of the first MMI device, causing a path length difference between an upper optical path via the first self-imaging point and a lower optical path via the second self-imaging point.

The present invention is related with the two-channel point-diffraction interferometer for testing the optical systems or optical elements. The two-channel point-diffraction interferometer comprising a laser source inducing a linearly polarized laser beam which is divided by a beam splitter to a working channel and to a reference channel whereas the one half of light as working channel is directed from the first collimator to the working collimator by a first single-mode optical fibre to keep polarization of light unchanged, and another half of light as reference channel is directed from the second collimator to the reference collimator by a second single-mode optical fibre to keep polarization of light unchanged.