Apparatus and methods are described use with a bodily sample that contains cells. A microscope (24) is focused, such that a focal plane of the microscope (24) at least approximately coincides with a level at which at least some cells belonging to the sample are at least partially disposed. At least one on-focus microscopic image of the sample, while the focal plane of the microscope (24) approximately coincides with the level. The microscope (24) is focused such that the focal plane of the microscope is offset with respect to the level, at least one off-focus microscopic image of the sample is acquired, while the focal plane of the microscope (24) is offset with respect to the level. A property of at least a portion of the sample is determined, at least partially based upon the on-focus and off-focus images. Other applications are also described.

The present disclosure is directed to a method of disturbance correction and to a laser scanning microscope carrying out this method. Specifically, it is directed to an image recording method according to the MINFLUX principle, in which a spatially isolated fluorescence dye molecule is illuminated at a sequence of scan positions by an intensity distribution with a local intensity minimum, and the number of fluorescence photons emitted by the fluorescence dye molecule is detected at each of the scan positions. The location of the molecule is determined with a high spatial resolution from the scan positions and the numbers of fluorescence photons. A disturbance is captured when illuminating the fluorescence dye molecule and detecting the fluorescence light, said disturbance being considered in corrective fashion when determining the location of the fluorescence dye molecule.

A method for adjusting a focus of an optical system includes focusing measurement light in a sample space using an optical arrangement. The measurement light is transmitted on a sample side of the optical arrangement through at least one optical medium. The measurement light reflected by a reflector and transmitted through a further optical arrangement is detected using a detector arrangement. A working distance between the optical arrangement and the reflector is ascertained based on the measurement light detected by the detector, wherein a focus of the measurement light lies on the reflector for the working distance.

An optical assembly in a laser scanning microscope, having an optical scanning unit providing a first pupil plane, a first beam deflecting device, made of a first scanner arranged on the first pupil plane, for scanning excitation radiation in a first coordinate direction, a first focusing device generating a second pupil plane, optically conjugated to the first pupil plane, and a second beam deflecting device for deflecting the excitation radiation. The second deflecting device is arranged on the second pupil plane. A second focusing device to generate a third pupil plane, is optically conjugated to the first pupil plane and the second pupil plane. A third beam deflecting device is arranged on the third pupil plane, and a variable beam deflecting device is provided to switch an optical beam path between a first beam path and a second beam path.

A computer-implemented method for determining a value for at least three setting parameters by means of an input unit in the form of a graphical user interface with an input cursor positionable in an input area is provided. At least two of the at least three setting parameters can be set independently of one another. The method includes determining a position of the input cursor within the input area; determining a coordinate of the position of the input cursor for each particular setting parameter of the at least three setting parameters as a function of a distance in each case of the position of the input cursor from at least one coordinate origin allocated to the particular setting parameter; and determining a value for each particular setting parameter of the at least three setting parameters as a function of the coordinate determined for each particular setting parameter.

A re-scan microscope for forming an image of a sample is disclosed. The system comprises an illumination optical system for directing, and optionally focusing, illumination light at the sample herewith providing an illumination light spot at the sample. The illumination light spot causes emission light from the sample. The microscope system further comprises a detection optical system for focusing at least part of the emission light onto an imaging plane of an imaging system herewith causing an emission light spot on the imaging plane. The microscope system also comprises a rotatable element for, when rotating, moving the illumination light spot over and/or through the sample and simultaneously moving the emission light spot over said imaging plane of the imaging system. The rotatable element comprises at least two reflective surfaces.

The invention relates to an optical assembly for scanning excitation radiation and/or manipulation radiation in a laser scanning microscope. The optical assembly according to the invention is characterized in that in addition to a first and a second focusing device, a third focusing device is provided in order to generate a third pupil plane which is optically conjugated to a first pupil plane, a third beam deflecting device is arranged on the third pupil plane in order to deflect the excitation radiation and/or manipulation radiation, a first beam deflecting means is provided between the second focusing device and the second pupil plane and the second pupil plane and the third focusing device in order to deflect the excitation radiation and/or manipulation radiation coming from the third focusing device while bypassing the second beam deflecting device in the direction of the second focusing device, a fourth focusing device is provided for generating a fourth pupil plane which is optically conjugated to the third pupil plane, and a variable second beam deflecting means is arranged on the fourth pupil plane in order to switch an optical beam path between a first beam path and a second beam path. The invention additionally relates to a laser scanning microscope.

A variable focal length lens apparatus is provided with a variable focal length lens in which a focusing position periodically changes in response to a drive signal that is input; a light source that emits detection light at an object via the variable focal length lens; an photodetector that receives the detection light that is reflected by the object, and outputs a light detection signal; a signal processor that, based on the light detection signal that is input, outputs a light emission signal that is synchronized to a focusing time point where the detection light is focused on a surface of the object; an illuminator that provides pulse illumination to the object with illuminating light, based on the light emission signal that is input; and an image capturer that captures an image of the object through the variable focal length lens.

An optical system for a light-sheet microscope comprises transporting optics configured to project, into a sample, a light sheet for illuminating a sample plane positioned obliquely to an optical axis of the transporting optics and to project the illuminated sample plane into an intermediate image space. The transporting optics comprises an interchanging system that includes a first light-deflection element and a second light-deflection element. The interchanging system is configured to switch an illumination direction along which the light sheet illuminates the sample by alternately introducing the first light-deflection element and the second light-deflection element into a beam path of the transporting optics. The first light-deflection element causes a partial image inversion in only one direction. The second light-deflection element causes a complete image inversion in two directions.

An objective for a microscope includes a displaceable lens group for correcting a spherical aberration. The displaceable lens group is designed in so that an offset of same in the direction perpendicular to the optical axis leads to only a small coma.