A method comprises: splitting laser light into sample light, reference light, and monitor light; routing the reference light into a reference arm of an OCT interferometer; routing the monitor light into a monitor device, which generates at least one optical monitor signal representing at least one time-dependent property of the monitor light; generating at least one electric monitor signal from the at least one optical monitor signal; illuminating in a point-shaped manner a sample with sample light, wherein the illumination point is guided on the surface of the sample along a predetermined trajectory; superimposing the light scattered by the sample with the reference light emerging from the reference arm to generate an electric OCT signal; wherein the at least one electric monitor signal and the electric OCT signal are AD-converted in alternating sequence, in each case equidistantly in time, to form a single digital data stream.

The present invention discloses a processing method for laser heterodyne interferometric signal based on locking edge with high frequency digital signal. A reference signal and a measurement signal of heterodyne interferometer, after being processed by photodetector, signal amplifier, filtering circuit, voltage comparator and high frequency digital edge locking module, are transferred to pulse counting synchronized latching processing module, to obtain entire cycle interference fringe numbers and filling pulse numbers in one interference fringe cycle, of the reference signal and the measurement signal; the numbers are transferred to a computer to obtain displacement and speed of a measured object; usage of a high frequency digital pulse signal to lock the rising edge of laser heterodyne interferometric signal can improve the gradient of the rising edge of interference signal and eliminate wrong pulse caused by noises, and improve the accuracy and stability of the processing for the following signals.

A programmable photonic integrated circuit implements arbitrary linear optics transformations in the spatial mode basis with high fidelity. Under a realistic fabrication model, we analyze programmed implementations of the CNOT gate, CPHASE gate, iterative phase estimation algorithm, state preparation, and quantum random walks. We find that programmability dramatically improves device tolerance to fabrication imperfections and enables a single device to implement a broad range of both quantum and classical linear optics experiments. Our results suggest that existing fabrication processes are sufficient to build such a device in the silicon photonics platform.

An inspection system is disclosed. In one embodiment, the inspection system includes an interferometer sub-system configured to acquire an interferogram of a sample. The inspection system may further include a controller communicatively coupled to the interferometer sub-system. The controller is configured to: receive the interferogram from the interferometer sub-system; generate a phase map of the sample based on the received interferogram, wherein the phase map includes a plurality of pixels; select a sub-set of pixels of the plurality of pixels of the phase map to be used for phase unwrapping procedures; perform one or more phase unwrapping procedures on the sub-set of pixels of the phase map to generate an unwrapped phase map; and generate a surface height map of the sample based on the unwrapped phase map.

The present invention relates to an ophthalmologic apparatus for acquiring depth information of an eye including a light source; a measurement optical path guiding measurement light; a reference optical path generating reference light; and a detector generating a detection signal containing an interference signal of the measurement light via the measurement optical path and the reference light coming from the reference optical path; an actuator driving at least part of the interference optical system to vary an optical path length difference between the measurement optical path and the reference optical path; a standard optical system including optical members disposed corresponding to the optical path length differences in one of the measurement optical path and the reference optical path. Optical members guide part of the measurement light or the reference light to the detector.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and a signal generator that outputs the reference signal input to the demodulation circuit and outputs a drive signal input to the optical modulator, in which Vd/Vr<10, where Vr is a voltage of the reference signal and Vd is a voltage of the drive signal.

An efficient method of evaluating the level of contrast of an OCT dataset is presented. The method develops a metric to segregate useful and not-so-useful data in one or more OCT B-scans, in order to reduce spurious subsequent analyses of the data by downstream segmentation algorithms. It is designed to be fast and efficient and is applied to determining autofocus of an OCT instrument real-time and in identifying a real image from its complex conjugate twin.

A proposed password is decomposed into basic components to determine and score transitions between the basic components and create a password score that measures the strength of the proposed password based on rules, such as concatenation, insertion, and replacement. The proposed password is scored against all known words, such as when a user is first asked to create a password for an account or access. The proposed password can also be scored against one or more previous passwords for the user, such as when the user is asked to change the user's previous password, to determine similarity between the two passwords.

An optical imaging system includes an optical radiation source (410, 510), a frequency clock module outputting frequency clock signals (420), an optical interferometer (430), a data acquisition (DAQ) device (440) triggered by the frequency clock signals, and a computer (450) to perform multi-dimensional optical imaging of the samples. The frequency clock signals are processed by software or hardware to produce a record containing frequency-time relationship of the optical radiation source (410, 510) to externally clock the sampling process of the DAQ device (440). The system may employ over-sampling and various digital signal processing methods to improve image quality. The system further includes multiple stages of routers (1418, 1425) connecting the light source (1410) with a plurality of interferometers (1420a-1420n) and a DAQ system (1450) externally clocked by frequency clock signals to perform high-speed multi-channel optical imaging of samples.

A wafer metrology system includes an interferometer sub-system and a controller. The interferometer sub-system is configured to generate an interferogram with an intensity map that corresponds to a modulated representation of a wafer surface. Further, the interferometer sub-system includes a detector configured to capture the interferogram. The controller includes one or more processors configured to generate a wrapped phase map of the interferogram, define patterns associated with features on the wafer, and correct phase discontinuities by applying a phase unwrapping procedure to the wrapped phase map to generate an unwrapped phase map and correcting phase discontinuities in the unwrapped phase map based on the patterns, or by combining phase unwrapping and correction in a unified step. Further, the patterns comprise two or more structures such that a portion of the unwrapped phase map associated with structures of the same type is continuous across borders separating structures of the same type.