Light-microscopy method, light microscope, illumination and detection device, and computer program

Abstract

The invention relates to a light-microscopy method, wherein a focus of the illumination light (B) is generated in the sample (2), wherein emission light (E) emanating from emitters in the sample (2) reaches a detector (6) in a detection beam path (5), wherein the detector (5) comprises a plurality of detector elements (60) which are arranged in a detection plane (D) and detect the emission light (E), wherein a first scanning device (7) and a second scanning device (8) are arranged one behind the other in the illumination beam path (4) and are each designed to shift the focus of the illumination light (B) in the sample (2), wherein the first scanning device (7) is arranged only in the illumination beam path (4) so that the emission light (E) is only de-scanned by the second scanning device (8), wherein a relative position (R) between a centre (Z) of a projection (P) of the detection plane (D) into the sample (2) and a focus position (F) of the illumination light (B) in the sample is determined, wherein detection signals detected by the detector elements (60) are evaluated taking the determined relative position (R) into account. The invention also relates to a light microscope (1), an illumination and detection device (100) and a computer program for carrying out the method.

Description

[0001] Light microscopic method, light microscope, illumination and detection device and computer program

[0002] Technical field of the invention

[0003] The invention relates to a light microscopic method, i.e. a method for light microscopic imaging or for locating and / or tracking individual emitters in a sample, as well as a light microscope, an illumination and detection device and a computer program for carrying out the method.

[0004] State of the art

[0005] Light microscopes are known from the prior art in which a sample can be illuminated with illumination light, e.g., excitation light, via two different scanning devices arranged one after the other in the beam path. The scanning devices typically have different properties; for example, one of the scanning devices may enable a high scanning speed but cover only a small field of view, while the other scanning device has a larger field of view but is slower. This is typically the case, for example, with a combination of an electro-optical scanning device and a mechanical scanning device such as a galvanometer scanner.

[0006] Such combinations of different scanners (sometimes also referred to as "tandem scanners") can be intended for various applications.

[0007] For example, a confocal laser scanning microscopy technique is known from the publication “Pixel hopping enables fast STED nanoscopy at low light dose” by B. Vingon, C. Geisler and A. Egner, Optics Express 28 (4), 4516-4528 (2020). In this technique, an excitation focus is scanned across the sample using a galvanometer scanner. The fluorescence light captured in specific sub-intervals of the pixel residence time is compared with a lower threshold to determine whether labeled sample structures are located at the corresponding position. If the lower threshold is not reached within the predefined time interval, a second electro-optical scanning device is used to jump the excitation focus to the next scan position. Similarly, the process can jump to the next pixel if the light recorded for a pixel reaches an upper threshold after only a sub-interval of the pixel residence time.This method protects the sample by reducing exposure and shortens the overall measurement time. Since pixel dwell times vary across the image field, deviations between the target and actual positions of the galvanometer scanner affect image quality. However, these deviations can be corrected with the faster electro-optical scanner. The emitted light is scanned by the galvanometer scanner and the electro-optical scanner to enable confocal detection with an avalanche photodiode.

[0008] This has the disadvantage that, due to the polarization dependence of the electro-optical scanner, half of the fluorescence light is lost, which negatively affects the signal-to-noise ratio.

[0009] In localization microscopy according to the MINFLUX principle, a tandem scanner, e.g. a combination of a galvanometer scanner and an electro-optic scanner, is also frequently used according to the state of the art.

[0010] MINFLUX is a method for locating or tracking isolated emitters in a sample. In this method, an intensity distribution of illumination light with a local minimum, e.g., a donut or bottle beam, is positioned at illumination locations around a pre-estimated, roughly estimated position of an isolated emitter. Emission light is recorded for these illumination locations, and a new estimated position of the isolated emitter is obtained from the illumination locations and their corresponding light quantities using a position estimator. Depending on the specific implementation of the method, a super-resolution image of the sample or a trajectory of a moving emitter can be determined from these estimated positions.

[0011] Various implementations of a MINFLUX method are described, for example, in the publications by F. Balzarotti et al., “Nanometer resolution imaging and tracking of fluorescent molecules with minimal photon fluxes”, Science 355 (6325), 606-612 (2017), KC Gwosch et al., “MINFLUX nanoscopy delivers 3D multicolor nanometer resolution in cells”, Nat. Methods, 17 (2), 217-224 (2020) and R. Schmidt et al., “MINFLUX nanometer-scale 3D imaging and microsecond-range tracking on a common fluorescence microscope”, Nat. Commun. 12 (1), 1478 (2021).

[0012] Many MINFLUX methods utilize a galvanometer scanner for coarse positioning of the illumination focus (and sometimes also for pre-localization, i.e., the initial determination of the roughly estimated emitter position), while the positioning of the minimum intensity distribution at the illumination positions is performed with a fast electro-optic scanner. Electro-optic scanners offer the advantage of very high scanning speed and positional accuracy. However, in addition to the small field of view, a disadvantage is their polarization dependence, which results in the loss of some of the fluorescence light when it is scanned by the electro-optic scanner.

[0013] Since such a loss of light is not tolerable with the low emission light quantities of the MINFLUX technique, the emission light in MINFLUX microscopes is usually only scanned by the galvanometer scanner, but does not pass through the electro-optical scanner on its way to the detector.

[0014] With such microscopes, perfect confocal detection does not occur, since the deflection of the focus by the electro-optical scanner affects the position of the emission light in the detection plane.

[0015] While the focus deflections caused by the electro-optical scanner are typically small in the MINFLUX technique compared to the size of the confocal pinhole, the deviation from confocal detection due to partial unscanning can still affect the amount of detected emission light and thus the position estimation, especially in early steps of iterative MINFLUX procedures where the deflections are larger.

[0016] Object of the invention

[0017] This leads to the task of providing a light microscopy method using two independent scanning devices, in which the advantages of the different scanning devices can be used without having to accept a loss of signal quality.

[0018] Solution

[0019] This problem is solved by the method, the light microscope, the illumination and detection device, and the computer program according to the independent claims. Advantageous embodiments are specified in the dependent claims and are described below.

[0020] Description of the invention

[0021] A first aspect of the invention relates to a light microscopy method, wherein a sample is illuminated with illumination light via an illumination beam path, a focus of the illumination light being generated in the sample, emission light emanating from emitters in the sample reaching a detector via a detection beam path that partially coincides with the illumination beam path, the detector comprising a plurality of detector elements arranged in a detection plane that detect the emission light, the detection plane being an image plane with respect to a focal plane in the sample in which the focus of the illumination light is located, and wherein a first scanning device and a second scanning device are arranged one after the other in the illumination beam path, each configured to shift the focus of the illumination light in the sample.and wherein the second scanning device is arranged in the common illumination and detection beam path, while the first scanning device is arranged only in the illumination beam path, so that the emission light is scanned only by the second scanning device, and wherein a relative position between a center of a projection of the detection plane into the sample and a focus position of the illumination light in the sample is determined, depending on a deflection of the illumination light by the first and second scanning devices as well as a deflection of the emission light by the second scanning device, wherein detection signals acquired by the detector elements are evaluated taking into account the determined relative position.

[0022] In this method, a c-scanned arrangement is implemented for the second scanning device, while a non-c-scanned arrangement is implemented for the first scanning device. Because the emission light is not descanned by the first scanning device, polarization-dependent scanners, such as electro-optical deflectors, can be used in the first scanning device without experiencing signal loss. In contrast to a single detector behind a pinhole aperture in the detection beam path, the use of a detector with multiple detector elements arranged in a single detection plane in this arrangement allows emission light to be detected even in situations where the first scanning device deflects the illumination light to such an extent that the emission light would no longer reach a single detector.In this case, the emission light travels along the detector in the detection plane and, depending on the deflection of the illumination light by the first scanning device, hits different detector elements.

[0023] According to the invention, this behavior is taken into account during the evaluation of the detection signals by determining a relative position between the center of the projection of the detection plane into the sample and the focus position, and by performing the evaluation based on this relative position. This center can, in particular, correspond to the point in the detection plane that the emission light strikes or would strike if the first scanning device did not deflect the illumination light (i.e., if it were in a zero position). In the latter situation, the focus of the illumination light in the sample and the emission light projected into the detection plane are confocal.

[0024] According to the invention, a deviation from confocality due to a deflection of the illumination light beam by means of the first scanning device (which manifests itself in the displacement of the relative position) is taken into account when determining a light microscopic image or a position of a single emitter in the sample.

[0025] The relative position can be represented, in particular, as a vector in a coordinate system whose origin can be the center of the projection of the detection plane onto the sample. Specifically, the detection plane can be projected onto the focal plane, so that this vector also lies in the focal plane. Alternatively, however, the detection plane can also be projected onto a plane within the sample that differs from the focal plane, so that the vector can have a non-zero axial component (parallel to an optical axis of the objective lens that focuses the illumination light onto the sample).

[0026] The relative position in the focal plane within the sample does not need to be explicitly determined, as long as a value is determined that is representative of the deviation from confocality. Alternatively, instead of the relative position, the displacement of the detection PSF in the detection plane, which depends on the deflection of the focus by the first scanning device, can be determined. From this, and taking the image scale into account, the relative position between the center of the projection and the focus position can then be determined.

[0027] The illumination light can be, for example, excitation light that induces light emissions from emitters in the sample. This can be achieved, for instance, through the fluorescence excitation of fluorophores. However, illumination light that is scattered or reflected by emitters in the sample also falls under the term "excitation light" in the context of this specification. Alternatively, the illumination light can also be suppression light that prevents light emissions from emitters in the sample. This includes, for example, STED light, which excites emitters in the sample from the excited state to the ground state through stimulated emission depletion. Naturally, the sample can also be illuminated with combined excitation and suppression light, which can, in particular, be focused together and scanned across the sample.

[0028] Depending on the type of illumination, the emission light can be, for example, fluorescent light, reflected light or scattered light.

[0029] In this application, emitters are understood to be objects which, when illuminated with light, can be considered point light sources for the purposes of the measurements according to the invention. Depending on the type of light, an emitter can therefore be, for example, a light-reflecting nanoparticle, a quantum dot, a fluorescent dye molecule (fluorophore), or a molecule or nanoparticle labeled with one or more fluorescent dye molecules. Depending on the size of the molecule and the spacing of the fluorophores, a molecule or nanoparticle labeled with several fluorophores can, of course, also have several emitters within the meaning of the definition used here.

[0030] Depending on the type of detector and the measurement method, detector elements can generate detection signals in different ways when they detect emission light. Certain detector elements, such as ava / anc / ie photodiodes (APDs) or hybrid detectors, are capable of detecting individual photons, and with suitable evaluation electronics, it may be possible to determine the arrival times of individual photons. With other detector types, such as photomultipliers, a photon rate—that is, the number of photons detected in a specific time interval—can be measured using an analog electrical detection signal.

[0031] In particular, the detector elements can be read independently of one another. Unlike cameras, where pixels are read out line by line or group by group, independent readout is possible, for example, with APD arrays or hybrid detector arrays. With independent readout of the detector elements, the detection signals can be evaluated more flexibly and accurately based on the relative position. APD arrays have the additional advantages of high measurement speed and a low dark count rate. Limitations exist with regard to the size of the detection area and the number of pixels. Recently, however, increasingly larger and more finely pixelated APD arrays have been developed. Fine pixelation is advantageous for the present invention because a larger number of pixels allows the evaluation of the detector signals to be adapted more precisely to the determined relative position, particularly with less signal loss.

[0032] The first and second scanning devices are not arranged parallel to each other, but rather one behind the other in the illumination beam path. This does not necessarily mean that the first and second scanning devices are directly adjacent to each other. Of course, further optical elements can be positioned between the first and second scanning devices.

[0033] According to one embodiment, the relative position is determined based on a position signal from the first scanning device and / or a position signal from the second scanning device. The position signal can, for example, be a target position signal sent by a control unit to the optical units of the first or second scanning device so that the optical units perform a target deflection of the illumination light. Alternatively, the position signal can, for example, be an actual position signal indicating the current state of the optical units of the first or second scanning device, such as the actual angular position of a mirror in a galvanometer scanner. Such a current state can be determined in various ways, for example, by means of a position encoder or an optical sensor. Galvanometer scanners, for example, have...often via an output position signal for feedback control, which represents a difference between a target position signal and an actual position of the galvanometer mirror, which can be caused in particular by a phase shift and / or damping.

[0034] In particular, knowledge of the target and / or actual positions of the scanning devices allows conclusions to be drawn about the actual deflection of the illumination light by the first scanning device and the second scanning device, which in turn makes it possible to determine the relative position between the focus of the illumination light in the sample and the center of the projection of the detection plane into the sample.

[0035] According to a further embodiment, the relative position is determined based on an actual position signal from the second scanning device, or based on a deviation between a target position signal and an actual position signal from the second scanning device, or estimated based on a target position signal from the second scanning device. For the first scanning device, it can be assumed, in particular, that the actual position signal corresponds to the target position signal. This can be the case, especially, if the first scanning device reacts significantly faster to the position signals than the second scanning device, e.g., in a combination of a first electro-optical scanning device (e.g., based on electro-optical deflectors) and a second mechanical scanning device (e.g., based on galvanometer scanners).In this case, the relative position can be determined, in particular, based on the target position signal of the first scanning device and the deviation between the target position signal and the actual position signal of the second scanning device. In a concrete implementation, for example, the relative position could be determined from the target position signal of a first electro-optical scanning device and the feedback signal (deviation between target and actual position) of a second galvanometric scanning device.

[0036] According to another embodiment, the first scanning device is controlled based on the deviation between the target position signal and the actual position signal of the second scanning device in order to correct the focus position. With some scanning devices, particularly those based on galvanometer scanners, positional errors regularly occur, which can lead to a deviation of the actual scan curve (i.e., the trajectory of the illumination light focus in the sample) from a desired scan curve. These errors can occur particularly under conditions where mechanical components such as galvanometer mirrors are subjected to high accelerations, for example, at reversal points of a raster scan or during irregular movements such as rapid jumps. If the first scanning device has a higher speed than the second scanning device, such deviations can advantageously be corrected, for example, by...A signal representing the deviation between the target position and the actual position of the second scanning device is fed to the control system of the first scanning device. In this way, the image quality can be further improved by avoiding scan artifacts. By taking the relative position into account during evaluation, as described in the invention, this avoidance of scan artifacts can advantageously be achieved without a loss of confocality.

[0037] According to another embodiment, the focus of the illumination light is deflected at a higher speed with the first scanning device than with the second. Here, "speed" refers specifically to the bandwidth of the scanning device, which indicates how many positions the scanning device can address within a given time interval, e.g., one second. The speed or bandwidth can be determined by various parameters, depending on the type of scanning device. These parameters can include, in particular, the response time of the control electronics, which elapses between the receipt of a control signal and the electronics' response. Furthermore, the time it takes, for example, for an electrical voltage to build up or an electrical current to flow in a driver circuit can influence the speed of the scanning device.In mechanical scanners such as galvanometer scanners, the inertia of moving optical elements such as galvo mirrors can also play a role in the scanning speed.

[0038] According to another embodiment, the relative position is determined based on a signal from a position sensor. Such a position sensor can be provided internally or externally with respect to the corresponding scanning device. Particularly in mechanical scanners such as galvanometer scanners, the position sensor can detect the current position of a movable optical element such as a galvo mirror. More generally, however, it is also possible for the position sensor to detect the position of the illumination beam at a suitable point in the illumination beam path.

[0039] The output signal of the position sensor can be used, as described above for position signals of the scanning devices, in particular additionally for correcting deviations between a target position and an actual position of components of one or both scanning devices, or for correcting deviations between a desired scan curve and an actual scan curve of the illumination light focus.

[0040] According to a further embodiment, the relative position is determined from a distribution of light emissions detected by the detector elements in the detection plane. A shift in the relative position between the focus of the illumination light in the sample and the center of the projection of the detection plane into the sample (which arises from different deflections of the illumination light by the first scanning device and the second scanning device when only partial scanning is performed) leads to a migration of the emission light in the detection plane, which can be analyzed by evaluating the detection signals of the individual detector elements.

[0041] According to a simple example, for each scan position of the illumination focus in the sample, the detector element or group of adjacent detector elements that captures the most emission light could be determined. Using the known dimensions of the detector and the known or measurably determined magnification of the microscope optics, the relative position can then be derived. As mentioned above, the relative position in the sample does not need to be explicitly calculated. Even considering the migration of the detection PSF image on the detector during evaluation is already covered by the present invention, since this indirectly determines and utilizes the relative position as defined.Provided that the detector and the computing and control electronics of the microscope can process this information quickly enough, in addition to taking the relative position into account in the evaluation according to the invention, a correction of the position signals for the first scanning device and / or the second scanning device could also be carried out on this basis.

[0042] According to another embodiment, the illumination light is excitation light that excites the emitters in the sample to emit light. In particular, the excitation light can excite the emitters to fluoresce.

[0043] According to a further embodiment, the illumination light is a blocking light that prevents the emission of light from emitters in the sample that are excited by additional excitation light. The blocking light can, in particular, be STED light. The additional excitation light can, in particular, illuminate the illumination beam path together with the blocking light and, in particular, be scanned across the sample by means of the first scanning device and / or the second scanning device.

[0044] According to a further embodiment, an intensity distribution of the illumination light with a local intensity minimum, in particular an intensity zero, is formed at the focus of the illumination light in the sample. The local intensity minimum can be a central intensity minimum, which is located, in particular, at the geometric focus. Furthermore, the local intensity minimum can, in particular (ideally), be an intensity zero. In particular, areas of increasing intensity border the local intensity minimum in at least one spatial direction (furthermore, in particular, in two or three spatial directions). The local minimum can be point-like, linear, or planar.

[0045] For example, the intensity distribution can be a donut shape, where the local minimum is located in the focal plane and is surrounded laterally (but not along the optical axis, i.e., axially) by areas of increasing intensity, or it can be a so-called bottle beam (sometimes also referred to as a 3D donut), where the local minimum is surrounded both laterally and axially by areas of increasing intensity. A donut shape can be created, for example, by phase modulating the illumination light in or near a pupil plane conjugate to the back aperture of the microscope objective, using a vortex phase pattern (also called a phase clock). A bottle beam can be generated by phase modulating the illumination pattern with a ring-shaped phase pattern in or near the pupil plane.Finally, intensity distributions with an area-like local minimum (sometimes also referred to as a crescent intensity distribution) can be achieved by phase modulation with a simply segmented phase pattern.

[0046] Intensity distributions with a local intensity minimum, which are scanned across a sample by scanning devices, are used, for example, in STED microscopy and MINFLUX microscopy.

[0047] In STED microscopy, a STED light intensity distribution with a local minimum is typically superimposed with a regular focus of fluorescence excitation light, with the maximum of the excitation light being aligned with the minimum of the STED light. The excitation light and the STED light are then scanned together across the sample. By narrowing the effective detection point spread function with the STED light, raster images with a resolution below the diffraction limit (i.e., better than the diffraction limit) can be acquired in this way.

[0048] In MINFLUX microscopy, the sample is typically illuminated with an intensity distribution of excitation light with a local minimum of illumination positions around a pre-estimated, roughly estimated position of a single emitter. An emission signal from the sample is recorded for each illumination position, and subsequently, the position of the single emitter is determined with increased accuracy using a position estimator. This process can then be repeated iteratively, achieving a resolution in the lower single-digit nanometer range in the prior art. Single emitters are defined as emitters (e.g., individual fluorophores or other point light sources) in a light-emitting state that are spaced above the diffraction limit or are otherwise optically separable.Variants of the MINFLUX technique have also been described in which an excitation light distribution with a maximum at the geometric focus is combined with a STED light intensity distribution with a local minimum and shifted to the aforementioned illumination positions in order to determine the position of the isolated emitter from the respective light emissions.

[0049] According to another embodiment, evaluating the detection signals acquired by the detector elements results in optical sectioning of the emission light by a synthetic aperture, wherein the center of the synthetic aperture is determined based on the specified relative position. Here, "synthetic aperture" refers to a group of detector elements of the detector comprising at least a first subgroup and a second subgroup, the second subgroup surrounding the first. For imaging or for position estimation of an emitter, only the emission signals of the detector elements of the inner subgroup are used.In this way, a pinhole aperture in the detection beam path can be simulated using a detector with multiple detector elements, and, as with the physical pinhole aperture, light from planes above and below the focal plane in the sample can be blocked ("optical sectioning"). The first subgroup can consist of a single detector element or multiple detector elements. Furthermore, the first and second subgroups can comprise all detector elements of the detector, or there can be at least one further subgroup of detector elements.

[0050] In a conventional confocal laser scanning microscope with a physical pinhole aperture and single detector (e.g. a photomultiplier or a single avalanche photodiode), the beam path is adjusted so that the emission light is centered on the pinhole aperture.

[0051] In the method according to the invention, the emission light can shift within the detection plane depending on the relative deflection of the illumination light by the first scanning device, due to the partial scanning of the emission light. In the embodiment described above, where the center of the synthetic aperture is determined based on the relative position, the first and second subgroups are selected for evaluating the emission signals depending on the location of the emission light spot within the detection plane. In particular, the subgroups are selected such that the maximum emission light distribution falls on the single detector element or a central detector element of the first subgroup. According to a further embodiment, the evaluation of the detection signals acquired by the detector elements includes a weighted summation of the detection signals.In other words, the detection signals of the detector elements are multiplied by weights, in particular where the weights can be real numbers from 0 to 1. A sum of the weighted detection signals is then calculated. This sum is used in the evaluation of the detection signals. Since the weights can also include the numbers 0 and 1, this embodiment specifically includes the implementation of a synthetic aperture described above, where the detector elements of the first subgroup are assigned a weight of 1 and the detector elements of the second subgroup are assigned a weight of 0. Of course, numerous alternatives are also possible. For example, a "semi-transparent" aperture (using a weight between 0 and 1 for the second subgroup) or an aperture with a "soft edge" (achieved through a gradual increase in weights from the outside to the inside) could also be implemented.

[0052] According to a further embodiment, the evaluation of the detection signals acquired by the detector elements comprises the processing of scan images of the sample acquired by individual detector elements, in particular by pixel reassignment or image deconstruction. In particular, a central detector element or a central group of detector elements is determined based on the ascertained relative position. In particular, a scan image can be acquired according to the principle of image scanning microscopy.

[0053] The term "pixel reassignment" describes a superposition of the individual images of the scan field of the individual detector elements. The pixels of the individual images are shifted relative to the central detector element or relative to the center of the detection plane by a so-called shift vector, depending on a position vector of the corresponding detector element. Optionally, these shifts are scaled with a scaling factor, and then the pixel intensities of the individual images are summed. A Sheppard sum can be calculated, meaning that theoretical shift vectors can be used. Alternatively, empirically determined shift vectors can also be used. These methods can lead to a significant increase in axial resolution through optical sectioning and a slight increase in lateral resolution (as with a resolution of approximately...).0.2 Airy Units closed aperture) while simultaneously improving the signal-to-noise ratio.

[0054] Image deconstruction is specifically a multi-image deconstruction based on the individual images from the detector elements. Various non-iterative or iterative algorithms can be used for this deconstruction. Such deconstruction allows for an increase in image resolution and signal-to-noise ratio.

[0055] In the context of the embodiments described above, the term "single image" refers to a scan image comprising pixels assigned to different scan positions of the illumination light's focus within the sample, with the pixel intensities representing the light emissions detected by the individual detector element for the corresponding scan positions. In this case, the respective detector element is initially read out like a single detector, with the resulting image being either confocal or non-confocal, depending on the relative position and the position of the corresponding detector element within the detection plane.

[0056] According to a further embodiment, the first scanning device comprises an electro-optic or acousto-optic deflector. Such scanning devices exhibit particularly high speed and are therefore especially suitable for the applications described here, such as correcting a slower scanning device, performing jumps, and controlling the illumination positions in MINFLUX microscopy.

[0057] According to another embodiment, the second scanning device comprises a mechanical scanner, in particular a galvanometer scanner. Mechanical scanners are relatively simple in design and often have a comparatively large field of view. However, the speed of these scanners is limited, particularly by the inertia of the mechanical components. Therefore, they can be readily combined with faster scanning devices such as electro-optical and acousto-optic scanners.

[0058] According to a further embodiment, the detection plane has a size that (taking into account the imaging scale) corresponds at least to the diameter of an Airy disk of the emission light projected from the sample onto the detection plane. In this way, the entire detection point spread function of the emission light can be imaged onto the detector. In particular, the size of the detection plane corresponds to at least 1.2 times, more specifically at least 1.5 times, and even more specifically twice the diameter of the Airy disk. The larger the area imaged onto the detection plane, the greater the displacement of the relative position between the focus position of the illumination light and the center of the projection of the detection plane onto the sample, caused by the deflection with the first scanning device, can be, and this displacement is taken into account during evaluation.This allows for more flexible use of the first scanning device. According to a further embodiment, the emission light is deflected by a deflecting element (e.g., comprising a piezoelectric tip-tilt actuator) arranged in the detection beam path in order to focus the emission light onto a specific area of ​​the detection plane.

[0059] Ideally, the detection plane should be large enough to cover the entire deflection range of the first scanning device, ensuring that the emitted light is always focused into the detection plane. However, when using currently available array detectors, it is often necessary to compromise between parameters such as size, pixelation, speed, dark count rate, and so on. Therefore, deflecting the emitted light with the deflection element allows for greater flexibility regarding the array detectors that can be used.

[0060] According to another embodiment, the sample is scanned with the first scanning device and / or the second scanning device at the focus of the illumination light, and a scan image of the sample is determined based on the evaluation of the detection signals. In the scan image, the pixels correspond to different scan positions of the illumination light focus within the sample. Thus, for example, an image can be acquired according to the principles of laser scanning microscopy, image scanning microscopy, and / or STED microscopy. In STED microscopy, as mentioned above, the sample is scanned with a combination of an excitation light focus and an intensity distribution of STED light with a local intensity minimum.

[0061] In particular, the scan image is acquired by scanning the sample with a combination of the first scanning device and the second scanning device.

[0062] According to another embodiment, the sample is scanned with focus using the first scanning device and / or the second scanning device such that different pixel residence times result for different scan pixels, particularly with a constant detector integration time. The term "pixel residence time" describes the duration over which the detector signal is integrated to obtain the pixel intensity for a pixel. It results from the scan speed (speed of the focus of the illumination light relative to the sample) and the detector integration time. In other words, the scan speed changes across the image field. The different scan speed can be an undesirable side effect of the respective scanning device (especially the second scanning device), which can be corrected, in particular, with the first scanning device, or the different scan speed can be desirable, e.g.,to perform jumps in the illumination light focus with the first scanning device.

[0063] One consequence of differing pixel dwell times is that positional errors of a scanning device, especially the second scanning device, can manifest as image artifacts. Such positional errors can then advantageously be corrected with the first scanning device without any loss of signal strength and / or signal quality.

[0064] According to a further embodiment, the focus of the illumination light is deflected by the first and second scanning devices such that the focus of the illumination light remains stationary at a scan position during the pixel dwell time and is abruptly shifted to another scan position after the pixel dwell time has elapsed. This can be achieved, for example, by controlling the scan position with the first and second scanning devices, whereby any deviation between a target state and an actual state of the second scanning device (in particular, a deviation between a target and actual position of optical elements such as galvo mirrors) is corrected by the first scanning device during a settling time. The first scanning device, in particular, has a higher speed than the second scanning device. The first scanning device could, for example, be a...The first scanning device is an electro-optical or acousto-optic scanning device, while the second scanning device can be, for example, a mechanical scanning device such as a galvanometer scanning device. By taking the relative position into account according to the invention, it is ensured that the scan image is always captured confocally despite the correction by the first scanning device.

[0065] According to a further embodiment, during a scan of the sample, the second scanning device checks at a first scan pixel whether the emission light detected by the detector elements exceeds or falls below a light threshold within a partial interval of a pixel residence time of the first scan pixel, wherein the focus of the illumination light is shifted to a position of another scan pixel by means of the first scanning device if the light threshold is exceeded or fallen below.

[0066] In this embodiment, so-called pixel hopping is implemented adaptively depending on the sample structure, particularly to protect the sample in areas of interest, e.g., from photobleaching or (in the case of a sample with living cells) phototoxicity. This technique, described in the prior art, is a variation of techniques such as CLEM (controlled light exposure microscopy), RESCUE (reduction of state transition cycles), or DYMIN (dynamic intensity minimum), in which the intensity of the illumination light is adaptively adjusted depending on the sample structure to protect the sample. However, it has the additional advantage of enabling faster image acquisition overall.

[0067] In this context, the method according to the present invention has the special advantage that fast scanning devices particularly well suited for pixel hopping, such as electro-optic or acousto-optic deflectors, can be used without having to descan the emission light through them with signal loss.

[0068] According to another embodiment, the scanning speeds of the first and second scanning devices vary over a scan area, but overall the focus of the illumination light in the sample shifts at a constant speed over the scan area.

[0069] In this process, the first scanning device can, for example, correct positional errors of the second scanning device, thus enabling an overall scan curve with pixel integration times homogeneously distributed across the image field. This is particularly important when the second scanning device is a mechanical device, such as a galvanometer scanner, and the first scanning device is a faster device, such as an electro-optical or acousto-optic scanner.

[0070] According to a further embodiment, at least one position of an isolated emitter in the sample is determined based on the evaluation of the detection signals by shifting an intensity distribution of the illumination light formed at the focus of the illumination light in the sample with a local intensity minimum, in particular an intensity zero point, from the first scanning device and / or the second scanning device at illumination positions of an illumination pattern by a first estimated position of the isolated emitter, and wherein, based on detection signals of the detector elements acquired for the different illumination positions, at least one further estimated position of the isolated emitter is determined with improved accuracy compared to the first estimated position.

[0071] This means that the method according to the embodiment described last is a MINFLUX method as defined here. The illumination light is primarily excitation light, but can also be STED light, which is additionally directed onto the sample along with focused excitation light.

[0072] The detector is specifically designed to detect individual photons. A detector with multiple detector elements suitable for single-photon detection is, for example, a so-called APD array.

[0073] The first estimated position of the isolated emitter can be determined using an independent method, such as a raster scan with an excitation light focus, pinhole orbit scanning, wide-field microscopy, or by illuminating activatable emitters in a spatially confined area with activation light. The illumination positions of the illumination pattern can be sequentially controlled, particularly with the first scanning device, which could be, for example, an electro-optic or acousto-optic scanner. The light emissions detected during a dwell time at each illumination position can then be assigned to that position. Alternatively, the intensity distribution can be continuously shifted across the illumination positions, for example, with the second scanning device, which could be, for example, a galvanometer scanner.In this way, the corresponding illumination position can be determined for each detected photon, i.e., the position where the minimum was located at the time of detection or registration of the photon. The continuous movement can be performed, for example, on a circular path or on non-circular paths such as Lissajous figures, hypotrochoids, epitrochoids, or similar paths.

[0074] The further estimated position can be calculated, for example, using a maximum likelihood estimator or a vector sum (equivalent to a least mean square estimator). The position estimator can be calibrated for specific measurement conditions.

[0075] In position estimation, the detection signals recorded by the individual detector elements for a given illumination position can simply be summed, or, for example, a weighted sum of the detection signals with weights from 0 to 1 can be determined, in particular where the weights can be determined depending on the position of the respective detector element in the detection plane.

[0076] In particular, the method can be performed iteratively by arranging the local intensity minimum of the illumination light at illumination positions around the further estimated position determined in the previous step and detecting light emissions from the isolated emitter, using the same illumination pattern or a modified illumination pattern (especially with a smaller extent and increased light intensity). This process can be repeated, in particular, until the accuracy of the position determination converges or until the emitter to be located stops emitting light.

[0077] According to a further embodiment, the local intensity minimum of the intensity distribution of the illumination light is located at the illumination positions by means of the first scanning device, wherein the detection signals of the individual detector elements for different illumination positions are weighted differently based on the determined relative position between the focus position of the illumination light in the sample and the center of the projection of the detection plane into the sample, and wherein the at least one further estimated position is determined based on the weighted detection signals. The weights can, in particular, be real numbers from 0 to 1.

[0078] In this way, position estimation errors caused by deviations from confocality depending on the deflection of the illumination light by the first scanning device without descanning the emission light by the first scanning device can be reduced.

[0079] According to a further embodiment, the center of the detection plane projection onto the sample is shifted to the first estimated position of the isolated emitter by the second scanning device before the intensity distribution is shifted to the illumination positions. In this way, the center of the image field corresponds specifically to the center of the illumination pattern. This ensures that the deviation from confocality has the same magnitude (but different directions) for all illumination positions, which can particularly facilitate the weighting of the detector signals.

[0080] According to a further embodiment, the positions of a first isolated emitter and a second isolated emitter are determined based on the evaluation by shifting the intensity distribution from the first scanning device at illumination positions by first estimated positions of the first emitter and / or the second emitter, and wherein, based on detection signals of the detector elements acquired for the various illumination positions, at least one further estimated position of the first emitter and the second emitter is determined with improved accuracy compared to the first estimated position.

[0081] Under certain circumstances, it may be possible to locate two different emitters in parallel using a MINFLUX method. First, the emitters could be spaced above the diffraction limit, and separate illumination patterns could be provided for the first and second emitters, between which the first scanning device switches back and forth. The present invention is advantageous in that the deviations from confocality that occur with a stationary image field (i.e., a stationary second scanning device) due to the deflection with the non-scanning first scanning device are relatively large and therefore contribute more to localization errors than with other MINFLUX methods.By weighting the detection signals of the individual detector elements differently depending on the determined relative position, which differs considerably for the two different illumination patterns, this error can be corrected using the method according to the invention.

[0082] In some cases, the first and second emitters can also be localized in parallel if they are separated by a distance below the diffraction limit, for example if they are emitters with different emission spectra or emission lifetimes, or if they blink asynchronously.

[0083] According to a further embodiment, the center of the projection of the detection plane in the sample with the second scanning device is positioned at a position between the first estimated position of the first emitter and the first estimated position of the second emitter, in particular at a midpoint between the first estimated position of the first emitter and the first estimated position of the second emitter.

[0084] This has the advantage that the deviations from confocality for illumination positions around the first emitter and illumination positions around the second emitter are of a similar order of magnitude. This facilitates the different weighting of the detection signals.

[0085] According to a further embodiment, a background value is determined based on detection signals acquired by the detector elements, and the further estimated position is corrected based on this background value. In particular, at least one detector element can be selected based on the determined relative position, and the background value is determined based on its detection signal.

[0086] For example, a detector element can be selected that lies outside the region onto which the detection point spread function of a single emitter is mapped. Light detected by this detector element is then highly likely to be background light.

[0087] According to another embodiment, the diameter of a synthetic pinhole aperture is adjusted based on the determined background value.

[0088] The synthetic aperture can be implemented as described above by dividing the detector elements into at least two groups, one of which is enclosed by another group. The detection signals of the outer group contribute little or not at all to the position estimation. The synthetic aperture allows background light to be blocked, thus improving the position estimation. Depending on the intensity of the background light (which may vary spatially within the sample or over time), the size of the synthetic aperture can be adjusted to block more or less background light.

[0089] Additionally, at least one detector element, whose detection signal is not used for position estimation due to the synthetic aperture, can be used for further background measurement in order to perform a background correction.

[0090] According to a further embodiment, the intensity minimum of the intensity distribution of the illumination light is shifted to a new position in the sample using the second scanning device, whereby a positional error of the second scanning device is corrected in a time interval during and / or after the shift to the new position by means of the first scanning device.

[0091] Particularly when the second scanning device is a mechanical scanner, such as a galvanometer scanner, rapid jumps to new sample positions—as might be necessary after localizing an emitter when moving to the position of a new emitter in a MINFLUX method—can cause oscillations of the optical elements, such as galvo mirrors. Advantageously, such positional errors can be corrected by the first scanning device, such as an electro-optical or acousto-optic scanner, thus reducing the waiting time required before the next illumination sequence for emitter localization begins.

[0092] A second aspect of the invention relates to a light microscope comprising an illumination optic configured to illuminate a sample with illumination light via an illumination beam path of the light microscope and to generate a focus of the illumination light in the sample, a detector arranged in a detection beam path of the light microscope which partially coincides with the illumination beam path, comprising a plurality of detector elements arranged in a detection plane which are configured to detect emission light emanating from emitters in the sample, wherein the detection plane is an image plane with respect to a focal plane in the sample in which the focus of the illumination light is located, and a first scanning device and a second scanning device, each configured to shift the focus of the illumination light in the sample.wherein the first scanning device and the second scanning device are arranged one after the other in the illumination beam path, and wherein the second scanning device is arranged in the common illumination and detection beam path, while the first scanning device is arranged only in the illumination beam path, so that the emission light is scanned only by the second scanning device.

[0093] The light microscope has a processing unit designed to determine the relative position between the center of a projection of the detection plane into the sample and a focus position of the illumination light in the sample. This relative position depends on the deflection of the illumination light by the first and second scanning devices, as well as the deflection of the emission light by the second scanning device. The processing unit then evaluates the detection signals acquired by the detector elements, taking this determined relative position into account. The processing unit is a logical component of the illumination and detection device, but does not necessarily have to be physically connected to it; for example, it can be implemented on a cloud server.

[0094] The light microscope is specifically designed to perform the procedure according to the first aspect.

[0095] A third aspect of the invention relates to an illumination and detection device for a light microscope comprising a first connection configured to connect the illumination and detection device to a light microscope, a second connection configured to couple illumination light into an illumination beam path of the illumination and detection device, a detector comprising a plurality of detector elements arranged in a detection plane, which are configured to detect emission light emanating from emitters in a sample, wherein the detection plane is an image plane with respect to a focal plane in the sample in which the focus of the illumination light is located, and at least one first scanning device configured to shift the focus of the illumination light in the sample, wherein the first scanning device is arranged only in the illumination beam path, but not in the detection beam path.so that the emission light is not scanned by the first scanning device, a computing unit designed to determine a relative position between a center of a projection of the detection plane into the sample and a focus position of the illumination light in the sample, dependent on a deflection of the illumination light by the first scanning device, and to evaluate detection signals acquired by the detector elements taking into account the determined relative position.

[0096] The computing unit is a logical component of the lighting and detection device, but does not have to be physically connected to it; it can, for example, be implemented on a cloud server.

[0097] The lighting and detection device is specifically designed to carry out the procedure according to the first aspect.

[0098] According to one embodiment, the illumination and detection device comprises a second scanning device configured to shift the focus of the illumination light in the sample, wherein the first scanning device and the second scanning device are arranged sequentially in the illumination beam path of the illumination and detection device, and wherein the second scanning device is arranged in a common illumination and detection beam path, such that the emission light is scanned by the second scanning device. Alternatively, the second scanning device can be part of the light microscope to which the illumination and detection device can be connected via the first connection.

[0099] A fourth aspect of the invention relates to a computer program comprising commands that cause the light microscope according to the second aspect or the illumination and detection device according to the third aspect to carry out the method according to the first aspect.

[0100] Further features and advantages of the light microscope according to the second aspect, the illumination and detection device according to the third aspect, and the computer program according to the fourth aspect will become apparent from the description of the method according to the first aspect.

[0101] Advantageous embodiments of the invention are described in the claims, the description, the drawings, and the accompanying explanations. The described advantages of features and / or combinations of features of the invention are merely examples and can have an effect alternatively or cumulatively.

[0102] Regarding the disclosure content (but not the scope of protection) of the original application documents and the patent, the following applies: Further features can be seen in the drawings – in particular the depicted relative arrangements and functional connections. The combination of features from different embodiments of the invention or from features of different claims is also possible, deviating from the chosen cross-references in the claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features from different claims. Likewise, features listed in the claims can be omitted for further embodiments of the invention, but this does not apply to the independent claims of the granted patent.

[0103] The reference numerals contained in the patent claims do not constitute a limitation of the scope of the subject matter protected by the patent claims. They merely serve the purpose of making the patent claims easier to understand.

[0104] Exemplary embodiments of the invention are described below with reference to figures. These do not limit the subject matter of this disclosure or the scope of protection.

[0105] Brief description of the characters

[0106] Fig. 1 shows an embodiment of a light microscope according to the invention; Fig. 2 schematically shows the projection of the detection plane into the sample to illustrate the method according to the invention;

[0107] Fig. 3 shows an embodiment of a lighting and detection device according to the invention.

[0108] Description of the characters

[0109] Fig. 1 shows a light microscope 1, which can be designed to image a sample 2 labeled with emitters using scanning microscopy (especially laser scanning microscopy) and / or to locate and / or track individual emitters in the sample 2 using a MINFLUX method.

[0110] The light microscope 1 has an illumination optic 3 for illuminating the sample 2 with illumination light B, in particular excitation light, wherein, according to the illustrated example, the illumination optic 3 comprises a light source 30 and an optional light modulator 31 for spatial modulation of the amplitude and / or phase distribution of the illumination light B. The light modulator 31 is required for the localization and tracking of individual emitters using a MINFLUX method in order to generate an intensity distribution of the illumination light B with a local intensity minimum, e.g., a donut or a bottle beam, in the sample 2, but is not required if the light microscope 1 is used for imaging by scanning microscopy. The illumination light B illuminates the sample 2 via an illumination beam path 4 that runs between the light source 30 and the objective 11.

[0111] According to one variant, the illumination optics 3 can also include an additional light source for generating blocking light, e.g., STED light, which is coupled into the illumination beam path 4 via another beam splitter and combined with the excitation light (not shown). In this case, a light modulator for spatially modulating the amplitude and / or phase distribution of the illumination light can also be located in the blocking light beam path in order to generate an intensity distribution of the blocking light with a local intensity minimum in the sample, e.g., a donut or a bottle beam.

[0112] The illumination beam path 4 is separated from a detection beam path 5 by means of a beam splitter 12, in which a detector 6 with several detector elements 60, e.g. an APD array, arranged in a detection plane D (see Fig. 2) is located.

[0113] The light microscope 1 comprises a first scanning device 7, in particular comprising at least one electro-optic or acousto-optic modulator, and a second scanning device 8, in particular a mechanical one, e.g. a galvanometric scanning device, wherein the second scanning device 8 comprises at least one movable optical element 80 (e.g. a galvanometer mirror) for deflecting the illumination light B. Both scanning devices 7, 8 are connected to a control unit 10 and are configured to deflect the illumination light B independently of one another when corresponding position signals are transmitted from the control unit 10 to the respective scanning device 7 or 8.

[0114] The illumination light B travels via the illumination beam path 4 from the light source 30 through the first scanning device 7, the optional light modulator 31, the beam splitter 12 and the second scanning device 8 to the objective 11, which focuses the illumination light B into the sample 2.

[0115] In sample 2, emitters excited by the illumination light B or further excitation light emit emission light E, which is focused by the objective 11 and passes via the detection beam path 5, i.e. from the objective 11 via the second scanning device 8, to the beam splitter 12, which reflects the emission light and from the beam splitter 12 to the detector 6.

[0116] The detector elements 60 of the detector 6 detect the emission light E and generate respective detection signals for the detector elements 60, which are transmitted to a computing unit 9.

[0117] The computing unit 9 can, for example, calculate a raster image of sample 2 from the detection signals, or, in the case of a MINFLUX method, estimate the position of a single emitter in sample 2 from the light emissions recorded for different illumination positions of the local intensity minimum of the intensity distribution of the illumination light B in sample 2.

[0118] Fig. 1 shows that the illumination beam path 4, through which the illumination light B travels from the light source 30 to the lens 11, coincides in the area between the lens 11 and the beam splitter 12 with the detection beam path 5, through which the emission light travels from the lens 11 to the detector 6.

[0119] The second scanning device 8 is thus located in the common illumination beam path 4 and detection beam path 5. The second scanning device 8 therefore scans the illumination light B across the sample 2 and detects the emission light E from the sample 2.

[0120] The first scanning device 7, on the other hand, is arranged between the light source 30 and the beam splitter 12, and is therefore located only in the illumination beam path 4, but not in the detection beam path 5. Accordingly, the illumination light B is scanned by the first scanning device 7 across the sample 2, but the emission light E is not scanned by the first scanning device 7. Due to this setup, the situation sketched in Fig. 2 can occur if the illumination light B is deflected by the first scanning device 7.

[0121] Fig. 2 shows the detector 6 with the detector elements 60 arranged in the detection plane D and its projection P (schematically represented with a simplified beam path without optical components) into the focal plane in the sample 2, in which the focus of the illumination light B is located. The focus is positioned at the focus position F in the sample 2.

[0122] In the depicted situation, the center Z of the detection plane D (which in this example corresponds to the position of the central detector element 60 in the third row and third column of the detector array) does not coincide with the focus position F due to the deflection of the illumination light B by the first scan device 7 and the failure of the first scan device 7 to descan the emission light E. The relative position R between the center Z and the focus position F is represented by a vector in Fig. 2.

[0123] According to the invention, this deviation from confocality is taken into account in the evaluation of the detection signals of the detector elements 60 by determining the relative position R from the computing unit 9 and incorporating it into the evaluation of the detection signals.

[0124] For example, the detection signals can be evaluated by the processing unit 9 in such a way that a synthetic aperture is realized using the detector 6. This aperture blocks light from planes above and below the focal plane in the sample 2, thus enabling optical sectioning. The center of the synthetic aperture, i.e., the detector element 60 or the group of detector elements 60 that forms the center of a sub-area of ​​the detection plane D where the detection signals of the detector elements 60 contribute to the measurement signal, can be determined based on the calculated relative position. Another possibility is to calculate a weighted sum of the detection signals, where the weights are determined based on the calculated relative position R.

[0125] Fig. 3 shows an embodiment of an illumination and detection device 100 according to the invention, with a first connection 110 for connecting to a light microscope 1 and a second connection 120 for connecting to a light source 30 for coupling illumination light B into an illumination beam path 4 of the illumination and detection device 100. Components identical to those of the light microscope 1 shown in Fig. 1 are marked with the same reference numerals. By connecting the second scanning device 8 of the light microscope 1 to the first connection 110 and the light source 30 to the second connection 120, the setup shown in Fig. 1 and described above is realized. In particular, the first connection 110 can be connected to a light input of the light microscope 1, e.g.a so-called port, in particular such that connection 110 ensures a predetermined orientation of the beam path of the illumination and detection device 100 to the light microscope 1. The second connection 120 can, for example, be a fiber coupler that inserts a laser source into the illumination beam path 4 of the...

[0126] Lighting and detection device 100 couples in.

[0127] Reference symbol list

[0128] 1 light microscope

[0129] 2 Sample

[0130] 3 Lighting optics

[0131] 4 Lighting beam path

[0132] 5 Detection beam path

[0133] 6 Detector

[0134] 7 First scanning device

[0135] 8 Second scanning device

[0136] 9 Calculation unit

[0137] 10 Control unit

[0138] 11 Lens

[0139] 12 beam splitters

[0140] 30 light sources

[0141] 31 Light modulator

[0142] 60 detector element

[0143] 80 Optical element

[0144] 100 Lighting and detection device

[0145] 110 First connection

[0146] 120 Second connection

[0147] B Lighting light

[0148] D Detection level

[0149] E emission light

[0150] F Focus position

[0151] P projection

[0152] Optical axis

[0153] R Relative position

[0154] Z Center

Claims

Patent claims 1. Light microscopy method, wherein a sample (2) is illuminated with illumination light (4) via an illumination beam path (4), wherein a focus of the illumination light (B) is generated in the sample (2), wherein emission light (E) emanating from emitters in the sample (2) reaches a detector (6) via a detection beam path (5) which partially coincides with the illumination beam path (4), wherein the detector (5) comprises a plurality of detector elements (60) arranged in a detection plane (D) which detect the emission light (E), wherein the detection plane (D) is an image plane with respect to a focal plane in the sample (2) in which the focus of the illumination light (B) is located, wherein a first scanning device (7) and a second scanning device (8) are arranged one after the other in the illumination beam path (4), each configured to shift the focus of the illumination light (B) in the sample (2),and wherein the second scanning device (8) is arranged in the common illumination beam path (4) and detection beam path (5), while the first scanning device (7) is arranged only in the illumination beam path (4), so that the emission light (E) is scanned only by the second scanning device (8), characterized in that a relative position (R) between a center (Z) of a projection (P) of the detection plane (D) into the sample (2) and a focus position (F) of the illumination light (B) in the sample (2), which depends on a deflection of the illumination light (B) by the first scanning device (7) and the second scanning device (8) as well as a deflection of the emission light (E) by the second scanning device (8), is determined, wherein detection signals acquired by the detector elements (60) are evaluated taking into account the determined relative position (R).

2. Method according to claim 1, characterized in that the relative position (R) is determined on the basis of a position signal from the first scanning device (7) and / or a position signal from the second scanning device (8), in particular wherein the relative position (R) is determined on the basis of an actual position signal from the second scanning device (8) or on the basis of a deviation between a target position signal and an actual position signal from the second scanning device (8), or is estimated on the basis of a target position signal from the second scanning device (8), further in particular wherein the first scanning device (7) is controlled on the basis of the deviation between the target position signal and the actual position signal from the second scanning device (8) in order to correct the focus position (F), nor furthermore, in particular, the focus of the illumination light (B) is deflected at a higher speed with the first scanning device (7) than with the second scanning device (8).

3. Method according to claim 1 or 2, characterized in that an intensity distribution of the illumination light (B) with a local intensity minimum, in particular an intensity zero point, is formed at the focus of the illumination light (B) in the sample (2).

4. Method according to one of the preceding claims, characterized in that the evaluation of the detection signals detected by the detector elements (60) effects optical sectioning of the emission light (E) by a synthetic pinhole aperture, wherein a center of the synthetic pinhole aperture is determined on the basis of the determined relative position (R).

5. Method according to one of the preceding claims, characterized in that the evaluation of the detection signals detected by the detector elements (60) comprises a weighted summation of the detection signals.

6. Method according to one of the preceding claims, characterized in that the evaluation of the detection signals recorded by the detector elements (60) comprises a calculation of scan images of the sample (2) recorded by individual detector elements (60), in particular by a pixel reassignment or an image unfolding, in particular wherein a central detector element (60) or a central group of detector elements (60) is determined on the basis of the determined relative position (R).

7. Method according to one of the preceding claims, characterized in that the detection plane (D) has a size that corresponds at least to the diameter of an Airy disk of the emission light imaged from the sample (2) into the detection plane (D).

8. A method according to any one of claims 1 to 7, characterized in that the sample (2) is scanned with the first scanning device (7) and / or the second scanning device (8) with the focus of the illumination light (B), wherein a scan image of the sample (2) is determined based on the evaluation of the detection signals, in particular wherein the sample is scanned with the focus by means of the first scanning device (7) and / or the second scanning device (8) such that different pixel dwell times result for different scan pixels or wherein scan speeds of the first scanning device (7) and the second scanning device (8) over a scan area vary over time, but overall a shift of the focus of the illumination light (B) in the sample (2) occurs at a constant speed over the scan area, furthermore in particular wherein during a scan of the sample (2) at a first scan pixel is checked by means of the second scan device (8) whether emission light (E) detected by the detector elements (60) exceeds or falls below a light threshold within a sub-interval of a pixel residence time of the first scan pixel, wherein the focus of the illumination light (B) is shifted to a position of another scan pixel by means of the first scan device (7) if the light threshold is exceeded or fallen below.

9. Method according to any one of claims 1 to 7, characterized in that, based on the Evaluation of the detection signals determines at least one position of a single emitter in the sample (2) by determining an intensity distribution of the illumination light (B) formed at the focus of the illumination light (B) in the sample with a local intensity minimum, in particular an intensity zero, from the first Scanning device (7) and / or the second scanning device (8) is displaced at illumination positions of an illumination pattern around a first estimated position of the isolated emitter, and wherein, based on detection signals of the detector elements (60) acquired for the various illumination positions, at least one further estimated position of the isolated emitter is determined with improved accuracy compared to the first estimated position, in particular wherein the local intensity minimum of the intensity distribution of the illumination light (B) is positioned at the illumination positions by means of the first scanning device (7),wherein the detection signals of the individual detector elements (60) for different illumination positions are weighted differently based on the determined relative position (R) between the focus position (F) of the illumination light (B) in the sample (2) and the center (Z) of the projection (P) of the detection plane (D) into the sample (2), and wherein the at least one further estimated position is determined based on the weighted detection signals, further in particular wherein the center (Z) of the projection (P) of the detection plane (D) into the sample (2) is shifted to the first estimated position of the isolated emitter with the second scanning device (8) before the intensity distribution is shifted to the illumination positions.

10. Method according to claim 9, characterized in that, based on the evaluation, the positions of a first isolated emitter and a second isolated emitter are determined by shifting the intensity distribution from the first scanning device (7) at illumination positions around first estimated positions of the first emitter and / or the second emitter, and wherein, based on the various Illumination positions detected detection signals of the detector elements (60) determine at least one further estimated position of the first emitter and the second emitter with improved accuracy compared to the first estimated position, in particular wherein the center (Z) of the projection (P) of the detection plane (D) in the sample (2) is positioned with the second scanning device (8) at a position between the first estimated position of the first emitter and the first estimated position of the second emitter, in particular at a midpoint between the first estimated position of the first emitter and the first estimated position of the second emitter.

11. Method according to claim 9 or 10, characterized in that a background value is determined on the basis of detection signals acquired by means of the detector elements (60), wherein the further estimated position is corrected on the basis of the background value, in particular wherein at least one detector element (60) is selected on the basis of the determined relative position (R), on the basis of whose detection signal the background value is determined, in particular wherein a diameter of a synthetic pinhole aperture is adjusted on the basis of the background value.

12. Method according to one of claims 9 to 11, characterized in that the intensity minimum of the intensity distribution of the illumination light (B) is moved to a new position in the sample (2) by the second scanning device (8), wherein a position error of the second scanning device (8) is corrected in a time interval during and / or after the relocation to the new position by means of the first scanning device (7).

13. Light microscope (1) comprising - an illumination optic (3) designed to illuminate a sample (2) with illumination light (B) via an illumination beam path (4) of the light microscope (1) and to create a focus of the illumination light (B) in the sample, - a detector (6) arranged in a detection beam path (5) of the light microscope (1) which partially coincides with the illumination beam path (4) and comprises a plurality of detector elements (60) arranged in a detection plane (D) which are configured to detect emission light (E) emanating from emitters in the sample, wherein the detection plane (D) is an image plane with respect to a focal plane in the sample (2) in which the focus of the illumination light (B) is arranged, - a first scanning device (7) and a second scanning device (8), each configured to shift the focus of the illumination light (B) in the sample (2), wherein the first scanning device (7) and the second scanning device (8) are arranged one behind the other in the illumination beam path (4), and wherein the second scanning device (8) is arranged in the common illumination beam path (4) and detection beam path (5), while the first scanning device (7) is arranged only in the illumination beam path (4), so that the emission light (E) is scanned only by the second scanning device (8), characterized in that the light microscope (1) has a computing unit (9) configured toto determine a relative position (R) between a center (Z) of a projection (P) of the detection plane (D) into the sample (2) and a focus position (F) of the illumination light in the sample, dependent on a deflection of the illumination light (B) by the first scanning device (7) and the second scanning device (8) as well as a deflection of the emission light (E) by the second scanning device (8), and to evaluate detection signals acquired by the detector elements taking into account the determined relative position.

14. Illumination and detection device (100) for a light microscope (1) comprising - a first connection (110) configured to connect the illumination and detection device (100) to a light microscope (1), - a second connection (120) designed to couple illumination light (B) into an illumination beam path (4) of the illumination and detection device (100), - a detector (6) comprising a plurality of detector elements (60) arranged in a detection plane (D) which are configured to detect emission light (E) emanating from emitters in a sample (2), wherein the detection plane (D) is an image plane with respect to a focal plane in the sample (2) in which the focus of the illumination light (B) is arranged, - at least a first scanning device (7) configured to shift the focus of the illumination light (B) in the sample (2), wherein the first scanning device (7) is arranged only in the illumination beam path (4) but not in the detection beam path (5), so that the emission light (E) is not scanned by the first scanning device (8), - a computing unit (9) which is configured to determine a relative position between a center (Z) of a projection (P) of the detection plane (D) into the sample (2) and a focus position (F) of the illumination light (B) in the sample (2), which depends on a deflection of the illumination light (B) by the first scanning device (7), and to evaluate detection signals acquired by the detector elements (60) taking into account the determined relative position.

15. Computer program comprising commands that cause the light microscope (1) according to claim 13 or the illumination and detection device (100) according to claim 14 to perform the method according to any one of claims 1 to 12.

Images