A method including: scanning a sample over a period of time using an electro-magnetic radiation source, the period of time including a first time period and a second time period, a sample portion of the electro-magnetic radiation source being directed to the sample in a sample arm of an optical interferometric system, and a reference portion of the electro-magnetic radiation source being directed to a reference arm of the optical interferometric system; applying, using a phase modulator, a phase shift comprising a first phase shift and a second phase shift to at least one of the reference portion or the sample portion of the electro-magnetic radiation source, the first phase shift being applied during the first time period and the second phase shift being applied during the second time period, the second phase shift having a difference of 90 degrees from the first phase shift.

In a measurement by means of OCT, when dispersion is present in a measured target or an optical system in the vicinity of the measured target, resolution of the measurement is degraded. One spectral interference fringe intensity is acquired when a phase difference between measurement light and reference light is not introduced, two spectral interference fringe intensities are acquired in a time-series manner when a phase difference of is introduced, a required calculation is performed based on the intensity, and a tomographic image not having reduced resolution due to dispersion is acquired.

The phase shift interferometer is configured to measure the shapes of measurement objects by acquiring a plurality of images of interference fringes while shifting the phases of the interference fringes. The interference fringes are provided with a phase difference of 90 relative to each other utilizing polarization of light. Images of the interference fringes are captured by two respective cameras while, in accordance with a conventional phase shift method, mechanically displacing a reference surface or a reference optical path to shift the phases. The phases of the interference fringes are calculated independently from the respective images acquired by the cameras and an average of the two phase calculation results is calculated.

A three-dimensional measurement device includes an optical system that: splits an incident light into two lights; radiates one light to a measurement object and the other light to a reference surface; and emits the combined light; a first irradiator that emits a first light that comprises a polarized light of a first wavelength and enters a first element of the optical system; a second irradiator that emits a second light that comprises a polarized light of a second wavelength and enters a second element of the optical system; a first camera that takes an image of the first light emitted from the second element when the first light enters the first element; a second camera that takes an image of the second light emitted from the first element when the second light enters the second element; and an image processor that performs measurement based on the images.

A truncated non-linear interferometer-based sensor system includes an input port that receives an optical beam and a non-linear amplifier that amplifies the optical beam with a pump beam and renders a probe beam and a conjugate beam. The system's local oscillators have a relationship with the respective beams. The system includes a sensor that transduces an input with the probe beam and the conjugate beam or their respective local oscillators. It includes one or more phase-sensitive detectors that detect a phase modulation between the respective local oscillators and the probe beam and the conjugate beam. Output from the phase-sensitive-detectors is based on the detected phase modulation. The phase-sensor-detectors include measurement circuitry that measure the phase signals. The measurement is the sum or difference of the phase signals in which the measured combination exhibit a quantum noise reduction in an intensity difference or a phase sum or an amplitude difference quadrature.

A 3D surface map of a workpiece is determined using an interferometric quantitative phase imaging technique. The workpiece includes a transparent thin film or layers stack. The 3D surface map is corrected based on a thickness and a refractive index of the transparent thin film or layers stack. This technique can be used with an inspection system configured to perform an interferometric quantitative phase imaging.

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 3D surface map of a workpiece is determined using an interferometric quantitative phase imaging technique. The workpiece includes a transparent thin film or layers stack. The 3D surface map is corrected based on a thickness and a refractive index of the transparent thin film or layers stack. This technique can be used with an inspection system configured to perform an interferometric quantitative phase imaging.