A device and method for phase imaging and element detection based on wavefront modulation are provided to overcome the disadvantages of an existing interferometry such as twin image elimination, limit resolution, under-sampling wavefront measurement, and multi-modal measurement. From the perspective of light field encoding, the accurate measurement to a complex amplitude of a light field to be measured is completely achieved by the iterative calculation, and at the same time, a twin image problem may be effectively eliminated, and it has the multi-modal (multi-wavelength) reconstruction ability. Theoretically, it is able to reach the diffraction limit resolution, may be widely used in phase imaging, optical element surface-type detection, polarization distribution measurement and the like, and it has a wide range of applications.

According to the present disclosure, there is provided a device (2) and a method for measuring a wavelength for a laser device. The device (2) for measuring a wavelength for a laser device includes: a first optical path assembly and a second optical path assembly. The first optical path assembly and the second optical path assembly constitute a laser wavelength measurement optical path. The second optical path assembly includes: an FP etalon assembly (11) and an optical classifier (13). The homogenized laser beam passes through the FP etalon assembly (11) to generate an interference fringe. The optical classifier (13) is arranged after the FP etalon assembly (11) in the laser wavelength measurement optical path, and configured to deflect the laser beam passing through the FP etalon assembly (11). The FP etalon assembly (11) allows two FP etalons (FP1, FP2) to share the same optical path for an interference imaging, and therefore a compact structure having a small volume, a simple design, and a high stability are achieved. In cooperation with the optical classifier (13), a precise measurement for a laser wavelength may be achieved, and at the same time a wavelength measurement range is large. It is suitable for an online measurement for a laser wavelength and a corresponding closed-loop control feedback.

A method for analyzing the wavefront effect of an optical system includes: illuminating a measurement mask (110, 310) with illumination light, producing an interferogram in a specified plane using a diffraction grating (150) from a wavefront from the illuminated measurement mask and traveling through the optical system; and capturing the interferogram with a detector (170). Different angular distributions of the illumination light incident on the measurement mask are produced via a mirror arrangement of independently settable mirror elements. A plurality of interferograms are captured in a plurality of measurement steps, wherein these measurement steps differ respectively in angular distribution of the illumination light that is incident on the measurement mask. A matching wavefront deviation portion in the measurement results obtained respectively in the measurement steps is ascertained to determine the respective system wavefront deviations of the optical system for the pupil regions illuminated respectively in the individual measurement steps.

A metrology system includes a first beam analysis system for analyzing at least one first measurement beam that was coupled from the excitation laser beam before a reflection on the target material and a second beam analysis system for analyzing at least one second measurement beam that was coupled from the excitation laser beam after a reflection on the target material. Each of the first beam analysis system and the second beam analysis system has at least one wavefront sensor system.

An optical receiver is provided that includes a detector array of multiple detector elements, and processing circuits coupled to the multiple detector elements. The detector array is configured to receive light from an external source, mix the light with light from a local oscillator to generate a spatial fringe across the detector array. The multiple detector elements are configured to convert respective portions of the spatial fringe incident on the multiple detector elements to corresponding electrical signals. The processing circuits are configured to process the electrical signals. This includes the processing circuits configured to sum those of the corresponding electrical signals from one or more of the multiple detectors, and subtract the sum from a second sum of those of the corresponding electrical signals from one or more other of the multiple detectors.

A method for analyzing the wavefront effect of an optical system includes: illuminating a measurement mask (110, 310) with illumination light, producing an interferogram in a specified plane using a diffraction grating (150) from a wavefront from the illuminated measurement mask and traveling through the optical system; and capturing the interferogram with a detector (170). Different angular distributions of the illumination light incident on the measurement mask are produced via a mirror arrangement of independently settable mirror elements. A plurality of interferograms are captured in a plurality of measurement steps, wherein these measurement steps differ respectively in angular distribution of the illumination light that is incident on the measurement mask. A matching wavefront deviation portion in the measurement results obtained respectively in the measurement steps is ascertained to determine the respective system wavefront deviations of the optical system for the pupil regions illuminated respectively in the individual measurement steps.

A system and method for low noise electromagnetic radiation measurement enabling to measure weak signals is provided. The electromagnetic radiation measurement system is configured for detecting weak electromagnetic radiation input signals overcoming the quantum limit. The electromagnetic radiation|measurement system includes at least one or more first 50/50 power splitter receiving the input signal; two or more identical balanced heterodyne receivers; two or more LNAs; one or more local oscillator (LO), one or more optical isolator; one or more second 50/50 power splitter; a digital correlator; and a computer or a similar computational device.

A spectroscope for measuring a spectrum of input light includes a fringe former that forms first fringes having a first pitch by splitting the input light, a diffraction grating that disperses each of the first fringes, a moire pattern former that forms a moire pattern by overlaying the first fringes that have been dispersed, on second fringes having a second pitch different from the first pitch, and an image pickup device that measures the spectrum of the input light by detecting the moire pattern. At least one of the fringe former and the moire pattern former includes a cylindrical lens array.

An optical receiver is provided that includes a detector array of multiple detector elements, and processing circuits coupled to the multiple detector elements. The detector array is configured to receive light from an external source, mix the light with light from a local oscillator to generate a spatial fringe across the detector array. The multiple detector elements are configured to convert respective portions of the spatial fringe incident on the multiple detector elements to corresponding electrical signals. The processing circuits are configured to process the electrical signals. This includes the processing circuits configured to sum those of the corresponding electrical signals from one or more of the multiple detectors, and subtract the sum from a second sum of those of the corresponding electrical signals from one or more other of the multiple detectors.

A method and an apparatus for measuring a coherence of a light source of a holographic display through steps of: photographing an interference pattern generated by light output from the light source; obtaining an interference pattern feature information with respect to the interference pattern from an interference pattern image of the interference pattern; and measuring the coherence of the light source based on the interference pattern feature information, are provided.