Imaging systems are provided allowing examination of different object regions spaced apart in a depth direction by visual microscopy and by optical coherence tomography. An axial field of view and a lateral resolution is varied depending on which object region is examined by the imaging system. The proposed imaging systems are in particular applicable for thorough examination of the human eye.

Methods and systems for focusing and measuring by mean of an interferometer device, having an optical coherence tomography (OCT) focusing system, by separately directing an overlapped measurement and reference wavefront towards a focus sensor and towards an imaging sensor; where a predefined focusing illumination spectrum of the overlapped wavefront is directed towards the focus sensor, and where a predefined measurement illumination spectrum of the overlapped wavefront is directed towards the imaging sensor. Methods and systems for maintaining focus of an interferometer device, having an OCT focusing system, during sample's stage moves.

The invention relates to an optical system for examining an eye by means of optical coherence tomography. The OCT system is designed in such a way that at least a first and a second state of the optical system can be selectively set by controlling the variable optical unit. In the first state, the OCT measurement beam has a measurement focus at an object distance from the objective, wherein the object distance has a value between 50 millimeters and 400 millimeters. In the second state, the measurement beam has defocusing at the same object distance, wherein the defocusing corresponds to a distance of a virtual or real focus from a position of the object distance that is greater than 100 millimeters.

Exemplary apparatus and method are provided for illuminating a sample. With such exemplary apparatus and/or method, it is possible to, using at least one source arrangement, provide at least one first electro-magnetic radiation. Using an optical system of an optics arrangement, it is possible to receive the first electro-magnetic radiation(s), and modifying the at least one first electro-magnetic radiation to be at least one second electro-magnetic radiation so as to be forwarded to the sample. Further, with the optical system, it is possible to extend the at least one second electro-magnetic radiation into or across the sample for a distance of at least 2 times the Raleigh range of a Gaussian beam when the optics arrangement and the sample are stationary with respect to one another. Additionally, using the optical system, it is possible to control a placement of a focus of the at least one second electro-magnetic radiation on or in the sample.

A distance measuring device for measuring a distance to an object to be measured comprises a beam splitter for splitting broadband coherent light emitted by a light source in measuring light which is guided through an object arm to the object to be measured and in reference light which is guided to a reference arm. A focusing optics with a focus being movable along an optical axis of the object arm is provided in the object arm, wherein the focusing optics comprises a movable optical element and is configured such that a movement of the movable optical element along the optical axis causes a higher movement of the focus of the focusing optics along the optical axis and wherein the movable optical element of the focusing optics is coupled to the reference arm such that the optical path length of the reference arm can be tracked synchronously with and dependent on the movement of the focus of the focusing optics.

A white light interferometric metrology device operates in the image plane and objective pupil plane. The interferometric metrology device extracts the electric field with complex parameters and that is a function of azimuth angle, angle of incidence and wavelength from interferometric data obtained from the pupil plane. Characteristics of the sample are determined using the electric field based on an electric field model of the azimuth angle, the angle of incidence and the wavelength that is specific for a zero diffraction order. A center of the pupil in the pupil plane may be determined based on a Fourier transform of the interferometric data at each new measurement and used to convert each pixel from the camera imaging the objective pupil plane into a unique set of angle of incidence and azimuth angle of light incident on the sample.

An interferometric measuring machine includes an exchangeable lens module system for an optical probe. The probe includes a lens body containing the optical apparatus of an interferometer and a lens module containing an objective lens along an object arm of the interferometer that can be exchanged with other lens modules for varying the measuring characteristics of the probe. The lens modules are adapted to accommodate objective lenses having different focal lengths while maintaining a desired optical path length of the object arm of the interferometer.

Imaging systems are provided allowing examination of different object regions spaced apart in a depth direction by visual microscopy and by optical coherence tomography. An axial field of view and a lateral resolution is varied depending on which object region is examined by the imaging system. The proposed imaging systems are in particular applicable for thorough examination of the human eye.

The invention relates to an optical system for examining an eye by means of optical coherence tomography. The OCT system is designed in such a way that at least a first and a second state of the optical system can be selectively set by controlling the variable optical unit. In the first state, the OCT measurement beam has a measurement focus at an object distance from the objective, wherein the object distance has a value between 50 millimeters and 400 millimeters. In the second state, the measurement beam has defocussing at the same object distance, wherein the defocussing corresponds to a distance of a virtual or real focus from a position of the object distance that is greater than 100 millimeters.

The present invention is related with the two-channel point-diffraction interferometer for testing the optical systems or optical elements. The two-channel point-diffraction interferometer comprising a laser source inducing a linearly polarized laser beam which is divided by a beam splitter to a working channel and to a reference channel whereas the one half of light as working channel is directed from the first collimator to the working collimator by a first single-mode optical fibre to keep polarization of light unchanged, and another half of light as reference channel is directed from the second collimator to the reference collimator by a second single-mode optical fibre to keep polarization of light unchanged.