A truncated non-linear interferometer-based atomic force microscope (AFM) includes an input port and a non-linear amplifier that renders a probe beam and a conjugate beam. The AFM includes local oscillators having a relationship with the probe beam and the conjugate beam. The displacement of the AFM's cantilever is transduced by the probe beam, and/or the conjugate beam or their respective local oscillators. The AFM's phase-sensitive detectors detect a phase modulation between the respective local oscillators and the probe beam and the conjugate beam. The detected phase modulation corresponds to the change in phase. The AFM's circuitry measures phase signals that are indicative of the cantilever displacement. The resulting measurement signals exhibit a quantum noise reduction in either the intensity difference or phase sum quadrature.

A vibration measurement device 10 includes an excitation unit (signal generator 11 and vibrator 12) for exciting an elastic wave to an inspection target S, an illumination unit (wavelength stabilized laser beam source 13 and illumination light lens 14) for performing stroboscopic illumination to a measurement region of a surface of the inspection target S using a wavelength stabilized laser beam source 13, a displacement measurement unit (speckle-sharing interferometer 15) for collectively measuring a displacement of each point of the measurement region in the back-and-forth direction by speckle interferometry or speckle-sharing interferometer. By using the wavelength stabilized laser beam source 13, an interference image can be obtained even when the inspection target S has large surface irregularities.

A tomographic imaging system includes a light source, a light irradiation unit that irradiates light to a transparent material composite thin film sample and a reference mirror and acquires an interference signal between light reflected and scattered from the sample and light reflected from the reference mirror, a light measuring unit that measures the interference signal acquired by the light irradiation unit, a light transmission unit that transmits the light output from the light source to the light irradiation unit and transmits the interference signal of the light transmitted from the light irradiation unit to the light measuring unit; and a signal processing apparatus that converts the interference signal of the sample, outputs the converted interference signal as a tomographic image, and monitors the interference signal acquired by the light irradiation unit to modulate intensity and a polarization state of the light input to the light irradiation unit.

A tomographic imaging system includes a light source, a light irradiation unit that irradiates light to a transparent material composite thin film sample and a reference mirror and acquires an interference signal between light reflected and scattered from the sample and light reflected from the reference mirror, a light measuring unit that measures the interference signal acquired by the light irradiation unit, a light transmission unit that transmits the light output from the light source to the light irradiation unit and transmits the interference signal of the light transmitted from the light irradiation unit to the light measuring unit; and a signal processing apparatus that converts the interference signal of the sample, outputs the converted interference signal as a tomographic image, and monitors the interference signal acquired by the light irradiation unit to modulate intensity and a polarization state of the light input to the light irradiation unit.

The invention provides a positioning system to determine an absolute position of a moveable target relative to a reference, comprising an interferometer system with a first light source to emit light at a fixed frequency and a second light source to emit light at at least two different frequencies. The positioning system is configured to determine, based on movement of the target, a phase difference curve associated with a first frequency of the second light source and a phase difference curve associated with a second frequency of the second light source as a function of a phase difference associated with the fixed frequency of the first light source and to determine a cross-point to determine the absolute position of the moveable target. The invention also relates to a lithographic apparatus and corresponding method.

An endoscopic imaging device (e.g., a catheter) comprises a light-transmitting tubing, at least one optical fiber disposed in the light-transmitting tubing, and at least one metalens. The metalens is optically coupled to the optical fiber and is configured to focus light from the optical fiber, through the light-transmitting tubing, and to a target point located outside of the light-transmitting tubing. The metalens includes a plurality of nanostructures. The nanostructures define a phase profile that corrects astigmatism caused by the light-transmitting tubing.

Interferometer displacement measurement system and method are disclosed, wherein, a measurement light is processed by a first polarization splitting prism, a first wave plate, a first splitting prism, an optical waveguide component and a reflector, and then is returned to a first photoeletric detector and a second photoeletric detector. The reference light is processed by a second polarization splitting prism, a second wave plate, a second splitting prism and a reflecting mirror, and then is returned to the first photoeletric detector and the second photoeletric detector. The first photoeletric detector forms a measurement signal according to the processed measurement light and the processed reference light, and the second photoeletric detector forms a reference signal according to the processed measurement light and the processed reference light. Displacement information of the object to be detected is determined according to the measurement signal and the reference signal.

Interferometer displacement measurement system and method are disclosed, wherein, a measurement light is processed by a first polarization splitting prism, a first wave plate, a first splitting prism, an optical waveguide component and a reflector, and then is returned to a first photoeletric detector and a second photoeletric detector. The reference light is processed by a second polarization splitting prism, a second wave plate, a second splitting prism and a reflecting mirror, and then is returned to the first photoeletric detector and the second photoeletric detector. The first photoeletric detector forms a measurement signal according to the processed measurement light and the processed reference light, and the second photoeletric detector forms a reference signal according to the processed measurement light and the processed reference light. Displacement information of the object to be detected is determined according to the measurement signal and the reference signal.

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; acquiring in-phase data based on a first interference between first backscattered electro-magnetic radiation during the first time period and the at least one of the reference portion or the sample portion subjected to the first phase shift; acquiring quadrature data based on a second interference between second backscattered electro-magnetic radiation during the second time period and the at least one of the reference portion or the sample portion subjected to the second phase shift; and determining a complex interference signal based on the in-phase data and the quadrature data.

A method of providing optical coherence tomography (OCT) imaging may comprise using an on-chip frequency comb source interfaced with an OCT system by a circulator as an imaging source and reconstructing OCT images from resulting spectral data from target tissue illuminated by the imaging source.