A low-coherence interferometer apparatus for determining information on interfaces of an object including: a polychromatic light source; an optical system generating a measurement optical beam and a reference optical beam; a delay line introducing a variable optical delay between the optical beams; detection optics combining the beams, and producing a spectral signal representative of an optical-power spectral density of the resulting interference signal; a control and processing module acquiring a plurality of spectral signals for a plurality of optical delays, determining, for each spectral signal, optical retardation information between interfering beams within a spectral measurement range, analyse the variation in the retardations, and assign the optical retardation determined on the basis of the different spectral signals to interface curves, corresponding to straight lines with positive, negative, zero or almost-zero gradient, depending on the respective optical delay of the acquisition of the spectral signals, and to deduce information of the object.

The present document relates to a scanning probe microscopy system and method for mapping nanostructures on the surface of a sample. The system comprises a sample support structure, a scan head including a probe comprising a cantilever and a probe tip, and an actuator for scanning the probe tip relative to the sample surface. The system also includes an optical source, and a sensor unit for obtaining a sensor signal indicative of a position of the probe tip. The sensor unit includes a partially reflecting element for reflecting a reference fraction and for transmitting a sensing fraction of the optical signal. It further includes directional optics for directing the sensing fraction as an optical beam towards the probe tip, and for receiving a reflected fraction thereof to provide a sensed signal. Moreover the sensor includes an interferometer for providing one or more output signals, and signal conveyance optics for conveying the sensed signal and the reference signal to the interferometer. The directional optics is configured for directing the sensing fraction such that at least a part of the sensing fraction is reflected by the probe tip such as to form the reflected fraction.

Apparatus and methods are described for optically analyzing an object having a plurality of layers, without needing to use a reference mirror. Light is generated using an extended broadband light source. The light is directed toward the object, such as to create respective images of the light source on the respective layers of the object. Light that is reflected from a point of the object is gathered into a conjugate point in a detector. The thicknesses of the plurality of layers at the point of the object are determined, by analyzing, within the gathered light, interference between light reflected from the plurality of layers of the object at the point. Other applications are also described.

A system for compensating for phase noise, with particular application in lidar, includes a compensation interferometer that receives a signal from a source, and splits it into a first and second path, with a path length difference between them. Typically the path length is significantly less than that of the return distance to a target. The output of the compensation interferometer, which consists of phase noise generated in time is vectorially summed during a time similar to a signal flight time to a target, and the result used to reduce phase noise present on measurements of a target. It further includes means for selecting such that competing noise elements are reduced or optimised.

A cascaded interferometric system for Fourier domain optical coherence tomography (OCT) in which the output of one sub-system interferometer is directed through a second sub-system interferometer for performing the Fourier transform in hardware.

Apparatus and methods are described for optically analyzing an object having a plurality of layers, without needing to use a reference mirror. An extended broadband light source produces light, and directs the light toward the object, such as to create respective images of the light source on the respective layers of the object. An imaging system gathers light that is reflected from a point of the object into a conjugate point in the detector. The detector determines the thicknesses of the plurality of layers at the point of the object by analyzing, within the gathered light, interference between light reflected from the plurality of layers of the object at the point. Other applications are also described.

What is proposed is a device (1) for optically measuring an object, comprising an interferometer (2) having a measurement arm (21), wherein the measurement arm (21) is provided for optically measuring the object, and comprising a focusing element (3) arranged within the measurement arm (21). According to the invention, the device (1) comprises a first retardation element (4) arranged within the measurement arm (21) and downstream of the focusing element (3), wherein the first retardation element (4) has a movable displacement element (42), by means of which the optical path length of the beam path of the measurement arm (21) is variable.

A device for measuring heights and/or thicknesses on a measurement object, includes (i) a first low-coherence interferometer for combining, in one spectrometer, a reference optical beam and a measurement optical beam originating from reflections of the light on interfaces of the measurement object, to produce a grooved spectrum signal with spectral modulation frequencies, (ii) apparatus for measuring an item of position information representative of the relative optical length, (iii) electronic and calculating apparatus arranged for determining at least one spectral modulation frequency representative of an optical path difference between the measurement optical beam and the reference optical beam, and for determining, by exploiting the item of information and the spectral modulation frequency, at least one height and/or thickness on the measurement object, and (iv) second optical apparatus for measuring distance and/or thickness with a second measurement beam incident on the measurement object on a second face opposite the measurement beam.

An optical sectioning apparatus using optical interference microscopy and fluorescence microscopy, including: a beam splitter capable of splitting an incident light beam into a reflected light beam and a transmitted light beam; a wide band light source for providing the incident light beam; a reference arm unit for making the transmitted light beam travel a round trip along an adjustable optical path; a short wavelength light source; a first dichroic splitter, with a first side facing the short wavelength light source and a third side facing the beam splitter, being capable of providing a light-blocking effect on wavelengths shorter than a preset wavelength; an objective lens, with a collimated side facing a second side of the first dichroic splitter; a sample carrier unit facing a focal side of the objective lens; and a projection lens and a sensor units for receiving an output light beam.

An optical sectioning apparatus using optical interference microscopy and fluorescence microscopy, including: a beam splitter capable of splitting an incident light beam into a reflected light beam and a transmitted light beam; a wide band light source for providing the incident light beam; a reference arm unit for making the transmitted light beam travel a round trip along an adjustable optical path; a short wavelength light source; a first dichroic splitter, with a first side facing the short wavelength light source and a third side facing the beam splitter, being capable of providing a light-blocking effect on wavelengths shorter than a preset wavelength; an objective lens, with a collimated side facing a second side of the first dichroic splitter; a sample carrier unit facing a focal side of the objective lens; and a projection lens and a sensor units for receiving an output light beam.