Imager with image rotation

Abstract

A method and system for optical subassembly include a light source, an objective lens, a transmission subassembly between the light source and the objective lens including an adjustment mechanism to adjust a position of a beam steering device and to direct an illumination light beam to a sample via the beam steering device and to direct the received light beam from the sample to a first location or a second location of the objective lens, and an emission subassembly between the objective lens and an image forming device to direct the received light beam from the first or second side of the sample to an image forming device via a light sheet imaging module, the transmission subassembly or the emission subassembly including a signal redirection module to direct a received light beam from the first side of the sample unrotated, and from the second side of the sample rotated.

Description

[0001] IMAGER WITH IMAGE ROTATION

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The contents of the related applications filed on even date herewith entitled “Automated Imaging in Content Screening” and “Thermal Management of Imaging Systems” are hereby incorporated in their entirety by reference. Furthermore, the priority filings corresponding to these two applications, US 63 / 614,714 and US 63 / 614,740, are incorporated by reference herein in their entirety. This application claims the priority benefit of US 63 / 614,743, the contents of which are expressly incorporated herein by reference in their entirety.

[0004] BACKGROUND

[0005] High content screening (HCS) is traditionally achieved through 2D imaging of thin samples. New trends in bioimaging require 3D imaging of more complex structures like organoids and spheroids, which cannot always be imaged with sufficient quality using the existing HCS instruments on the market. High contrast 3D imaging is possible through Selective Plane Illumination Microscopy (SPIM), also referred to as Oblique Plane Microscopy (OPM). However, being able to obtain a good quality focus, contrast and resolution of a resulting image generated via SPIM on an image capture device presents challenges to be addressed in order to create a 3D HCS imaging platform that produces quality images.

[0006] SUMMARY

[0007] In one aspect, an optical subassembly includes a light source, an objective lens in proximity to a sample stage configured to hold a sample, and a transmission subassembly arranged between the light source and the objective lens. The transmission subassembly includes an adjustment mechanism to adjust a position of a beam steering device proximal to the light source and configured to direct an illumination light beam from the light source to the sample stage. The beam steering device can direct the illumination light beam to one of a first location of the objective lens and a second location of the objective lens opposite the first location with respect to a central axis thereof. An emission subassembly is arranged along an optical pathway between the objective lens and an image forming device, and can direct a received light beam from one of a first side of the sample and a second side of the sample to an image forming device via a light sheet imaging module. At least one of the transmission subassembly and the emission subassembly can include a signal redirection module. In a first configuration of the signal redirection module the received light beam is directed from a first side of the sample unrotated, and wherein in a second configuration the received light beam is directed from a second side of the sample rotated.

[0008] The signal redirection module can include a mirror, a mirror combination, a spatial light modulator, and a prism. The received light beam can be rotated at an angle in a range of 90° to 270°. The received light beam can be rotated 180°. The beam steering device can include an adjustable mirror. The adjustable mirror can rotate around an axis of rotation thereof by one of a first angle and a second angle different from the first angle. The adjustable mirror at the first angle directs the received light beam to the first location of the objective lens and the resulting received light beam is emitted from the first side of the sample, and the adjustable mirror at the second angle directs the received light beam from the light source at the second location of the objective lens, and the resulting received light beam is emitted from the second side of the sample. The emission subassembly can direct the received light beam to the image forming device via an imaging module. The imaging module can include a first portion configured to receive the reflected light beam along a first axis, and a second portion having relay lenses and relay objectives to receive the light beam from the first portion along a second axis at one of the relay lenses and to return the received light beam to the first portion from one of the relay objectives. The first portion can direct the received light beam received from the second portion to the image capture device. The signal redirection module can be located within the first portion so as to receive the received light beam. The signal redirection module can be located in the transmission subassembly on a light path of the light source signal between the light source and the objective lens. The signal redirection module can be located in the emission subassembly on a light path of the sample signal between the objective lens and the imaging module. The beam steering device can include one of a mirror, a prism and a spatial light modulator. The adjustment mechanism can rotate or translate at least one of the mirror, the prism and the spatial light modulator. At least one of the transmission subassembly and the emission subassembly includes one or more lenses, one or more objectives, and one or more mirrors.

[0009] According to another aspect, a method includes generating an illumination light beam at a light source, directing the generated illumination light beam to a first location of an objective lens in proximity to the sample via a beam steering device, directing, via a light sheet imaging module located along an optical path between the objective lens and an image forming device, a received light beam emitted from a first side of the sample to the image forming device, directing the generated illumination light beam to a second location of the objective lens via the beam steering device, and directing, via the light sheet imaging module, the received light beam from the second side of the sample to the image forming device in the light sheet imaging mode, the second side being opposite the first side.

[0010] The method can also include forming a first image of the first side of the sample in the light sheet mode, forming a second image of the second side of the sample in the light sheet mode, and forming a composite image of the first side and the second side of the sample in the light sheet imaging mode. Directing the received light beam from the first side of the sample can include directing the received light beam to the image forming device unrotated. Directing the received light beam from the second side of the sample can include rotating the sample signal before directing the sample signal to the image forming device. Directing the received light beam from the first side of the sample and directing the rotated received light beam from the second side can be performed independently. Directing the received light beam from the first side of the sample and from the second side of the sample can include directing the sample signal through a signal redirection module. The signal redirection module can be located in the light sheet imaging module.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIGS. 1A-1C are schematic views of an imaging system including SPIM, according to examples of this disclosure.

[0013] FIG. 2 is a schematic view of a movable SPIM imaging selection module in an imaging system, according to various examples of this disclosure.

[0014] FIGS. 3A-3C are schematic views of beam steering in an imaging system including SPIM, according to examples of this disclosure. FIGS. 4A-4C illustrate examples of a signal redirection module, in accordance with examples of the disclosure.

[0015] FIG. 5 is a flowchart illustrating a method of performing light sheet imaging, in accordance with various examples of the disclosure.

[0016] FIG. 6 depicts a block diagram of a computing device.

[0017] DETAILED DESCRIPTION

[0018] Selective Plane Illumination Microscopy (SPIM), also referred to as Oblique Plane Microscopy (OPM) or light sheet microscopy, is a technique for obtaining optically sectioned images of a sample. SPIM uses two objective lenses, separated by an angle such as, e.g., an angle of 90°, relative to one another and both objective lenses are used to view the same sample. One lens is used to illuminate only a thin “sheet” within the sample and the second lens is used to produce a diffraction-limited image of this sheet. A drawback of SPIM is that two objective lenses are required and this gives rise to disadvantages at least because the alignment of the two objective lenses is typically difficult to achieve and to maintain. Another disadvantage is that it is mechanically difficult to arrange for the two objective lenses to be placed close enough to one another so that a high numerical aperture lens can be used to collect the light while still being able to produce a thin sheet of illumination, and that a special sample holder is required to be used. Other challenges include the fact that improving the image quality, e.g., improving the image focus, contrast and / or resolution, is difficult to achieve in oblique plane imaging in its current configuration. The use of OPM in large, complex 3D samples, may be substantially limited due to the impact of the refractive index and the sample structure on the illumination angle when imaging deep in a vertical, or “Z” direction.

[0019] Furthermore, dual illumination SPIM and the variations of illumination from two sides Light Sheet Fluorescence Microscopy (LSFM) have the advantage to create a more uniform composite image or isotropic image from the two vantage points that also reduces the loss of data when there is an obstruction to one of the illumination paths. When using a single objective SPIM technique, it is typically difficult to employ a similar approach to illuminate and view from two or more sides, and if the sample is near the wall of the sample holder and only one view is possible, then it may not be possible to image the sample unless the entire sample holder is rotated. There is therefore a need to be able to use a technique similar to SPIM, but that allows for the imaging of opposing sides of a sample, and forms a composite image of the sample based on the images of the opposing sides at an image forming device. Examples of the disclosure allow viewing of the opposite side of the sample by rotating the sample emission signal to re-use pre-aligned remote focus optical elements, and adding mirror combinations or prisms to provide an adequate rotation method for the sample emission signal. Example systems may allow to independently control illumination to pair with the side of the object to be viewed. Motorized components which translate, tilt, or rotate a prism, a mirror system, or a spatial light modulator may be used to make this adjustment, as discussed in greater detail below. It may thus be possible to calibrate the illumination angle and position with the emission path in any viewing orientation, and to choose paths to image if there is a risk of obstruction by, e.g., the sample stage or sample holder. As such, examples of the disclosure may allow to create an isotropic image from two or more views as well as improve contrast and resolution of the resulting image.

[0020] Various examples of the disclosure further include a beam steering device configured to steer the beam of a light signal emanating from a light source towards different locations of an objective lens, and thus towards various locations, or sides, of the sample proximal to the objective lens. As the sample emits a sample signal as a result of the illumination, each side of the sample emits a different signal, and the images formed by the imaging device from both emitted sample signals may be combined to form a composite image of the sample. In an example, when sample signals of opposite sides of the sample are emitted, one of the sample signals may be rotated by, e.g., a signal redirection module, so as to be imaged at the image forming device without the need for establishing a different light path to accommodate the sample signal. Such a signal redirection module may include e.g., a truncated rightangle prism, also referred to as Dove prism, a two air-spaced components prism, also referred to as Pechan prism, or any other prism configuration that may independently direct a signal therethrough when the prism is rotated into various positions.

[0021] Thus, the signal redirection modules described herein may be utilized in any type of multimodal imaging system that includes SPIM in addition to at least one other imaging modality, e.g., brightfield, widefield, or confocal imaging. Such systems are described below with respect to the examples depicted in FIGS. 1A-1B. In an example of a multimodal imaging system, the system may first determine sample locations of interest using brightfield, widefield, and / or confocal modes, followed by SPIM imaging. Based on the determination of the sample locations of interest and various parameters of the system (such as the location of the side walls), the side of the sample to be imaged during SPIM the imaging process is determined. Alternatively, or additionally, during SPIM imaging, if it is determined that the sample is too close to an obstruction such as, e.g., the side wall of the sample holder, the opposite side of the sample may also be imaged from the opposite side. In another example, SPIM imaging may be performed in various orientations by capturing various sides of the sample, and a composite image of the sample based on the images of the sample taken under various orientations may be formed. In other examples, the signal redirection module may be utilized in imaging systems that are dedicated solely to SPIM imaging. Such a system is described below with respect to the example depicted in FIG. 1C.

[0022] FIG. 1 A is a schematic view of an imaging system, according to examples of this disclosure. The imaging system 100A is an example of an optical arrangement that may be of a multimodal type (including a SPIM modality and one or more other imaging modalities). In general, when operating in an imaging modality other than SPIM, focusing module 175 is in the path of returned light RL. This condition is depicted in FIG. 1A. When operating in a SPIM modality, a SPIM or imaging module 200 affects the location of the focusing module 175 in the path of returned light RL, thus acting effectively to change the focusing effect of the focusing module 175, with further effects on the returned light RL as described below.

[0023] For example, the returned light RL may be a fluorescent emission. Fluorescent emissions are the emissions of light from a sample at one wavelength due to excitation at another wavelength. Fluorescent excitation and emission processes are a form of inelastic scattering of incident light and can be used to characterize a sample by providing information about the types of fluorescent emissions (number of photons emitted, and wavelength of emitted photons) based on a particular intensity and spectrum of incident light. “Autofluorescence” refers to fluorescence that occurs naturally upon exposure of a sample to an excitation source, while fluorescence more broadly can refer either to autofluorescence or to exogenous fluorescence via the application / integration of external fluorophores like fluorescent dyes, fluorescent proteins, and fluorescent nanoparticles or other fluorescence treatments.

[0024] Confocal fluorescence microscopy is a laser-based technique where radiation of one wavelength excites a fluorescent response in a sample that is detected at second wavelength or range of wavelengths. Extensive libraries of fluorescent dyes have been developed to target different functional and structural elements of biological materials, for example cells, tissues, and organisms. Fluorescence microscopy enables researchers and clinicians to create, visualize and analyze micrographs of a sample where each color represents the distribution of specific target structures within the biological material. Various fluorescence microscopy techniques are described, for example in Renz, “Fluorescence Microscopy — A historical and Technical Perspective,” Cytometry Part A, Vol 83, pp. 767-779 (2013) and Sanderson et al., “Fluorescence Microscopy,” Cold Spring Harb Protoc. 2014(10): pdb.top071795. doi: 10.110 l / pdb.top071795.

[0025] FIG. 1 A describes an optical light source 110 such as, e.g., a laser, a light emitting diode (LED), an incandescent lamp, a halogen lamp, an arc lamp, and the like, configured to generate an illumination light or incident light IL, a fiber selector 120 configured to direct the illumination light IL to a given or desired light path, filters 130 and 135, an ocular lens 190, and an image forming device 195 such as, e.g., a camera 195. The fiber selector 120 may include a selectable first optical fiber 122 and a selectable second optical fiber 124, each selectable optical fiber 122 or 124 being configured to emit the illumination light IL therethrough towards a given signal path.

[0026] In examples, either or both of the first optical fiber 122 and the second optical fiber 124 may be or include a fiber bundle, the bundle including a plurality of fibers.

[0027] FIG. 1 A also describes a first lens 140 and a second lens 150, a mirror 160, and an objective lens 170. The objective lens 170 may face a sample 180 arranged on a movable stage 185, and the sample 180 is movable via the movable stage 185 in a planar or XY direction that is parallel to the objective lens 170. The controller 102 is configured to switch between various modes including the SPIM mode and, e.g., select the optical fibers 122 and 124 in view of a desired imaging mode. Operation of at least one of the laser 110 or the fiber selector 120 is controlled via the controller 102 to direct the illumination light IL in a SPIM light path, the illumination light IL being referred to in this case as the illumination signal.

[0028] The selectable first optical fiber 122 of the fiber selector 120 is configured to emit the illumination light IL therethrough towards the light sheet light path, and the selectable second optical fiber 124 is configured to emit another light source signal therethrough towards, e.g., a widefield or confocal light path (not shown). The controller 102 may be coupled to or include a computing system such as, e.g., the computer system 600 discussed below with respect to FIG. 6.

[0029] In operation during the SPIM mode, also referred to herein as light sheet mode, the laser 110 generates the illumination light IL that is transmitted through fiber selector 120 to the dichroic mirror 125. The illumination light IL received at the dichroic mirror 125 is reflected onto a mirror 160 and onto objective lens 170. The path of the illumination light IL is radially off-centered with respect to the objective lens 170 or other focusing optic, such that the illumination light IL reaches the sample 180 at a non-perpendicular angle with respect to the surface of the sample 180. In an example, the light path between the illumination source 110 and the sample 180 is referred to as an optical subassembly. One example of such an optical subassembly can include fiber selector 120, dichroic mirror 125, mirror 160, and objective 170, though in alternative embodiments there may be more, fewer or different elements as part of the optical subassembly that accomplish the same effect of directing the illumination light IL to the sample at an angle.

[0030] The illumination light IL is received at the objective lens 170 in an off-centered configuration and is transmitted to the sample 180 at an incident angle a, as illustrated in FIG. 1. FIG. 1 also depicts an optical light, which may be an emission light or a so- called reflected light “RL,” which is used herein for clarity. Emitted or reflected light is reflected from the sample 180 at an oblique angle that is substantially equal and opposite to the incident angle a, and travels through the objective lens 170 in an off- centered configuration in the opposite direction of the illumination light IL and at an oblique angle to a central axis of the objective lens 170. In another example, the optical light may be a fluorescent light or signal that follows the same path as the returned light RL and is characterized by the emission of light by a sample that has absorbed light or other electromagnetic radiation. The returned light RL travels through an off-centered radial portion of the objective lens 170, is reflected from an off-centered radial portion of the mirror 160, and travels through an off-centered radial portion of the dichroic mirror 125 and of the second lens 150. Upon leaving the second lens 150, the returned light RL continues to travel through an off-centered radial portion of the first lens 140, through filters 130 and 135, and onto a focusing module 175. The focusing module 175 may be movable and may be configured to receive the off-centered returned light RL and convert the returned light RL from an off-centered beam to a parallel beam 178 onto ocular lens 190. The ocular lens 190 is configured to focus the parallel beam returned light RL onto the image acquisition device 195 such as, e.g., camera 195.

[0031] When the system 100A is in the SPIM imaging modality, the SPIM imaging module 200 is positioned nearby and may be mechanically coupled to the focusing module 175. Thus, in a multimode imaging system, and as described elsewhere herein, the SPIM imaging module 200 may be moved into the path of the returned light RL, when in the SPIM imaging mode, and moved out of the path of the returned light RL when in a different imaging mode. The imaging module 200 receives the off-center returned light RL and converts the returned light RL from an off-centered beam to a parallel beam 178 onto ocular lens 190. The ocular lens 190 is configured to focus the parallel beam returned light RL onto the image forming device 195 such as, e.g., camera 195. An example of the imaging module 200 is depicted in FIG. 2.

[0032] Relevant to the imaging system 100A of FIG. 1A which depicts the focusing module 175, the imaging module 200 may include a signal redirection module 172 that is configured to direct the received sample signal therethrough either unrotated or rotated by a given angle, when the imaging system 100A is imaging in the SPIM mode. In the figures, the signal redirection module 172 is illustrated as any one of signal redirection modules 172A, 172B, 172C, 172C’ or 172D. Accordingly, the discussion herein of the “signal redirection module 172” corresponds to any one of the above signal redirection modules. The given angle of rotation of the received sample signal may be in a range of 90° to 270°, and may be, e.g., an angle of 180°. In other examples, the angle of rotation may be lower than 90° and greater than 270°. The signal redirection module 172 may be or include, e.g., a prism, a mirror, or a combination of both. Although FIG. 1A illustrates the signal redirection module 172 being located in, e.g., the imaging module 200, the signal redirection module 172 may also be located in other locations of the system 100A on the light path of the emitted returned light RL, for example, before to the filter 130 or elsewhere. In some configurations, a signal redirection module 172 may be located in both the illumination and emission paths of the system.

[0033] Regardless of location of the signal redirection module 172, during operation, when the sample signal is received from a first side of the sample, e.g., an off-centered first side, then the sample signal may be directed through the signal redirection module 172 without being rotated. In FIG. 1A, the first side of the sample 180 is the side where the illumination light IL reaches the sample from the objective lens 170 on the right of the sample (viewed from the illumination direction). When the sample signal is received from a second side of the sample opposite the first side, e.g., on the left of the sample 180 in FIG. 1A, then the sample signal may be rotated by the signal redirection module (e.g., the module 172) by a given rotation angle such as, e.g., a rotation angle in a range of 90° to 270°, or, e.g., an angle of 180°.

[0034] In a multimode version of the imaging system 100 A, the movable imaging module 200 may be movable in the Z direction, (relative, e.g., to the XY movement of the stage 185) as illustrated in FIG. 1 A, and may be configured to be placed on the path of the returned light RL in order to convert the returned light RL from an off-centered beam to the parallel beam 178 that then projects onto ocular lens 190. For example, when the fiber selector 120 directs the illumination light IL to an off-centered portion of the dichroic mirror 125 in a light sheet mode, then the movable imaging module 200 is moved along the Z direction to be placed on the light path of the returned light RL. On the other hand, when the fiber selector directs the illumination light IL to a center portion of the dichroic mirror 125 and through a path corresponding to another imaging mode such as, e.g., a widefield or confocal mode (not shown), then the movable imaging module 200 may be moved off the light path of the returned light RL, such that the returned light RL simply passes through the focusing module 175. In other examples, the beam steering device 127 receives light directly from the light source 110 (without the fiber selector 120 therebetween). In another example, the light path of the returned light RL between the sample 180, the objective lens 170, the mirror 160, the dichroic mirror 125, the second lens 150, the first lens 140, the filters 130 and 135, the focusing module 175 and the ocular lens 190 may be referred to herein, or included within, as an emission subassembly. In another example, the light path of the illumination light IL between the light source 110, the beam steering device 127, the dichroic mirror 125, the mirror 160, and the objective lens 170, may be referred to herein, or included within, as a transmission subassembly. Alternatively, any one of the first lens 140 and the second lens 150 may be movable with respect to each other along the optical axis in order to adjust the distance therebetween. Adjusting the distance between the first lens 140 and the second lens 150 may improve the quality, e.g., the focus, contrast and resolution, of the image formed on the image forming device.

[0035] For each of the images, a focus score can be determined. As described above, a focus score can be based on contrast, resolution, field of view, or some combination of these factors. A focus score is a data type that is related to the purpose of the imaging process — for example, sufficient contrast to ensure signal-to-noise that sufficient resolution to make out a feature of interest, or sufficient field of view to capture an entire feature or field of interest.

[0036] Where there are multiple images obtained for a given layer, the images can be ranked for each layer based on the focus score associated with that image. The instrument settings associated with the highest-ranked images can be compared and combined to determine which settings provide the best results on each layer, or across all layers. These instrument settings can be stored for each layer as candidate instrument positions, and can be specific to the highest-ranking positions for remote focus position, the pupil position and the steering position, for example.

[0037] Once these instrument settings are stored, one or more final images can be acquired for each of the layers based on at least one candidate instrument position associated with each layer.

[0038] The imaging system 100A further includes beam shaping optics or a beam steering device 127 which is illustrated herein as, e.g., an adjustable mirror. The beam steering device 127 may also be or include a spatial light modulator instead of an adjustable mirror. The beam steering device 127 may also be referred to herein as beam steering mirror 127, or pupil position adjustment mirror 127, and is configured to reflect the illumination light IL received form the fiber selector 120 onto various portions of the dichroic mirror 125. The imaging system 100A may also include an adjustment mechanism 129, which may include at least one motorized actuator to enable a translational movement of the beam steering device 127. In another example, the adjustment mechanism 129 may be configured to rotate the beam steering device 127 by an angle around an axis thereof. In yet another example, both rotational and translational movements may be performed by the adjustment mechanism 129. The adjustment mechanism 129 may be configured to translate the beam steering device 127 along a direction “X” of the illumination light IL, or a direction “X” that is parallel to the direction of the illumination light IL. Although the adjustment mechanism 129 is discussed above and illustrated in the drawings as a single mechanism, the adjustment mechanism 129 may be or include an individual rotation mechanism and / or an individual translation mechanism. FIGS. 3A-3C further discussed below illustrate the above-discussed configurations in greater detail.

[0039] FIG. IB is a schematic view of another example of an imaging system 100B, according to examples of this disclosure. Components of the imaging system 100B are described above in the context of FIG. 1A and, as such, are not necessarily described further. In the imaging system 100B of FIG. IB, the signal redirection module 172, is on the light path of the illumination light IL, as opposed to being located along the path of returned light RL, as depicted in FIG. 1 A. More specifically, the signal redirection module 172 is illustrated in FIG. IB as being on the path of illumination light IL between the beam steering device 127 and the dichroic mirror 125, but may also be in other locations of the transmission subassembly on the light path of the illumination light IL. Generally, with respect to FIG. IB, the signal redirection module 172 may be at various locations on the path of illumination light IL in the transmission subassembly. This configuration of imaging system 100B may be appropriate for multimodal imaging systems utilizing SPIM in addition to another imaging modality.

[0040] FIG. 1C is a schematic view of another example of an imaging system 100C, according to examples of this disclosure. Components of the imaging system 100C are described above in the context of FIGS. 1A and IB and, as such, are not necessarily described further. The imaging system 100C of FIG. 1C is characterized by an absence of a fiber selector such as, e.g., the fiber selector 120 illustrated in FIGS. 1 A and IB. Accordingly, in FIG. 1C, the illumination light IL is generated by the light source or laser 110 directly onto the beam steering device 127. The configuration illustrated in FIG. 1C corresponds to a single mode imaging device where the only mode of imaging is, e.g., SPIM imaging, which reduces or removes the need for a fiber selector. In such a SPIM-dedicated imaging system 100C, the signal redirection module 172 A may be located on the path of returned light RL (as described in FIG. 1 A), and / or the signal path redirection module 172B may be located on the path of illumination light IL (as described in FIG. IB). In other examples of a SPIM-dedicated imaging system 100C, the laser 110 may be replaced with the laser 110 / fiber selector 120 configuration of FIGS. 1A, IB.

[0041] FIG. 2 shows the returned light RL received at a mirror 281 that redirects the returned light RL with respect to the initial light path of the returned light RL onto a first lens 282, also referred to herein as first relay lens 282. The returned light RL is received in a radially off-centered portion of the relay lens 282 and onto another relay lens 283, also in a radially off-centered portion thereof. The lens 283 then directs the returned light RL to a radially off-centered portion of a mirror 284 which redirects the returned light RL at an angle with respect to the incident returned light RL and towards a first relay objective 286. Other optical arrangements are possible, but importantly the returned light RL is directed such that it is received off-center at the first relay objective 286. The mapping of the pupils of first and second relay objectives 286 and 287 results in spatially-resolved data that can be used as described herein. Movement of the upper stage 204 affects the spatial position of the incoming returned light RL beam and these lenses map that incoming position to a 1 : 1 spatially-resolved position on the objectives 286, 287, either centered or offset depending upon the incoming RL.

[0042] The first relay objective 286 transmits that redirected returned light RL to a second relay objective 287, the second relay objective 287 converts the radially off- centered returned light RL to a parallel beam onto a mirror 289. The mirror 289 then redirects the received parallel beam of the returned light RL out of the movable imaging module 200 as a parallel beam 288. As a result, the RL, initially entering the movable imaging module 200 as a radially off-centered light signal or light source signal, is converted to a centered parallel beam 288 that is usable to an image acquisition device such as, e.g., the camera 195 illustrated in FIGS. 1A-1C. The relay objectives 286 and 287 may be aligned and fixed in space on, e.g., a platform, to preserve the alignment therebetween.

[0043] The movable imaging module 200 may include a first portion 204 and a second portion 208. The first portion 204, also referred to herein as movable portion 204, includes the mirrors 281 and 289. The second portion 208, also referred to herein as fixed portion, includes a plurality of relay lenses such as, e.g., relay lenses 282, 283, and a plurality of relay objectives such as, e.g., relay objectives 286 and 287, and the mirror 284. The first portion 204 is configured to receive the returned light RL along a first axis, e.g., the axis of the RL.

[0044] Moving mechanism 279 is mechanically coupled to first portion 204 to cause translation thereof relative to second portion 208. Movement mechanism 279 can be controlled by, e.g., the controller 102 illustrated in FIGS. 1A-1E. In other examples, both the portions 204 and 208 may be movable via, e.g., the moving mechanism 279. In alternative examples, the portion 204 is fixed and the portion 208 is movable via, e.g., the moving mechanism 279. Although only two relay lenses 282 and 283 are depicted and discussed herein, more than two relay lenses (or other optical handling components) may be part of the movable imaging module 200, or part of the second portion thereof 208. 204 and 208 are independent but optically aligned to each other. First portion 204 can select whether light is transmitted through second portion 208 or not, and returns the output back into the widefield path, creating a multimodal system for use in OPM.

[0045] Accordingly, in operation, when the SPIM or light sheet mode is activated, the first portion 204 is placed on the light path of the optical signal or returned light RL on the optical axis of the ocular lens 190, and directs the returned light RL from the first portion 204 into the second portion 208 before returning to the first portion 204 and out of mirror 289 as parallel beam 288. Ln particular, the second portion 208 receives, from the first portion 204 along an axis of the Z direction, the optical signal returned light RL at the first relay lens 282. The second portion 208 transmits the returned light RL from the relay lens 282 to the second relay lens 283 and to a first relay objective 286, then from the first relay objective 286 to the second relay objective 287, and then transmits the returned light RL to the first portion 204 from the second relay objective 287. The first portion 204 then transmits the returned light RL received from the second relay objective 287 to an image capture device such as, e.g., the camera 195 illustrated in FIGS. 1A-1C. The second portion 208 may include a moving mechanism 280 that is configured to adjust, typically along the Z direction or axis, a position of at least one of the first relay lens 282 and the second relay lens 283 based upon an instruction from the controller 102. As shown in FIG. 2, a sufficiently large face of the mirror 281 can receive returned light RL at a variety of Z positions, and translation of first portion 204 in the Y axis can also reflect incoming returned light RL to different spatially-resolved positions within second portion 208. Whether in the Z direction or some other direction, a controller (e.g., 102) can be used to implement relative movement between first portion 204 and second portion 208. Although two relay lenses 282 and 283 are illustrated in FIG. 2, other relay lenses may be present in the second portion 208 to relay the returned light RL from the first relay lens 282 to the first relay objective 286. It should be understood that mode selection module 204 is not limited to use in SPIM, and could be used for SPIM or any number of optical modules that could be assembled on an instrument.

[0046] In examples where the imaging module 200 is utilized in a multimode imaging system, it is necessary to move the imaging module 200 into and out of the path of returned light RL. Such an imaging module 200 may therefor include a first portion 204 and a second portion 208, either or both of which may be movable. In one example, the first portion 204, referred to in this example as the movable portion 204, includes the mirror 281 / signal redirection module 172, as well as the mirror 289. The second portion 208, referred to herein in this example as the fixed portion, includes a plurality of relay lenses such as, e.g., relay lenses 282, 283, and a plurality of relay objectives such as, e.g., relay objectives 286 and 287, and the mirror 284. Although portions 204 and 208 are referred to above as being movable with respect to one another, in various examples, portions 204 and 208 may be fixed together in space and movable together so that the distance between the portions 204 and 208 remains constant. The first portion 204 is configured to receive the returned light RL along a first axis, e.g., the axis of the returned light RL, and may be movable via a moving mechanism 279 controlled by, e.g., the controller 102 illustrated in FIGS. 1A-1B. In other examples, both the portions 204 and 208 may be movable together via, e.g., the moving mechanism 279. Although only two relay lenses 282 and 283 are depicted and discussed herein, more than two relay lenses may be part of the movable imaging module 200, or part of the second portion thereof 208.

[0047] Accordingly, in operation, when the SPIM or light sheet mode is activated in a multimode system, at least the first portion 204 is placed on the light path of the returned light RL and on the optical axis of the ocular lens 190, and directs the returned light RL from the first portion 204 into the second portion 208 before returning to the first portion 204 and out of mirror 289 as parallel beam 288. In particular, the second portion 208 receives, from the first portion 204 along an axis of the Z direction, the returned light RL at the first relay lens 282. The second portion 208 directs the returned light RL from the relay lens 282 to the second relay lens 283 and to a first relay objective 286, then from the first relay objective 286 to the second relay objective 287, and then directs the returned light RL to the first portion 204 from the second relay objective 287. The first portion 204 then directs the returned light RL received from the second relay objective 287 to an image capture device such as, e.g., the camera 195 illustrated in FIGS. 1A-1B. The second portion 208 may include a moving mechanism 280 that is configured to adjust, along the Z direction or axis, a position of at least one of the first relay lens 282 and the second relay lens 283. Although two relay lenses 282 and 283 are illustrated in FIG. 2, other relay lenses may be present in the second portion 208 to relay the returned light RL from the first relay lens 282 to the first relay objective 286.

[0048] FIGS. 3A-3C are schematic views of beam steering in an imaging system, according to examples of this disclosure. FIGS. 3A and 3B depict alternative or complementary beam steering configurations. In FIG. 3 A, the beam steering device 127, proximal to the light source 110 or the fiber selector 120, is configured to reflect light received from the light source 110 onto the objective lens 170 and to be rotatable around an axis thereof so as to reflect the light signal received from the fiber selector 120 onto the dichroic mirror 125 at varying angles such as, e.g., angles al and a2. In other examples, the beam steering device 127 receives light directly from the light source 110 with no fiber selector such as the fiber selector 120 therebetween. For example, a rotation of the adjustable mirror at a first angle reflects the light received from the light source at a corresponding first location of the objective lens, and a rotation of the adjustable mirror at a second angle different from the first angle reflects the light received from the light source at a corresponding second location of the objective lens, the second location being different from the first location. The axis of rotation of the beam steering device 127 may be along an axis or direction that is angled with respect to both the Z direction and the X direction. As the angle of reflection ai varies, the location of incidence of the illumination light IL on the sample 180 varies. Accordingly, it is possible to vary the location of the illumination light IL received at the dichroic mirror 125, and consequently the location of the illumination light IL received at the sample 180, by varying the angle ai of incidence of the illumination light IL received from the light source 110.

[0049] FIG. 3B is an imaging system including SPIM, according to examples of this disclosure. In FIG. 3B, the mirror adjustment mechanism 129 is configured to translate the beam steering device 127 along a longitudinal direction X that is parallel to the direction of the light received from the light source 110 or fiber selector 120, which varies a position of the pupil of the beam steering device 127. For example, a longitudinal movement of the beam steering device 127 at a first distance along the longitudinal direction X reflects the light received from the light source 110 at a corresponding first location of the dichroic mirror 125, and a longitudinal movement of the beam steering device 127 at a second distance along the longitudinal direction X different from the first distance reflects the light received from the light source 110 at a corresponding second location of the dichroic mirror 125, the second location being different from the first location. Accordingly, the beam steering device 127 is configured to be translatable along a direction “X” that is the direction of the illumination light IL, or a direction parallel to the direction of the illumination light IL so as to reflect the light signal received from the fiber selector 120 onto the dichroic mirror 125 at varying locations xO, xl and x2. As the location xi of incidence of illumination light IL on the dichroic mirror 125 varies, the location of incidence of the illumination light IL on the objective 170, and then on the sample 180, varies.

[0050] FIG. 3C illustrates the imaging of two sides of a same sample 180, according to various examples of the disclosure. For example, as the beam emanating from the beam steering device 127 illustrated in FIGS. 3A and 3B may be incident on one side of the sample 180 via a side of the objective lens 170, illustrated in FIG. 3C as Side A. The beam emanating from the beam steering device 127 may also be incident on an opposite side of the sample 180 via another side of the objective lens 170, illustrated in FIG. 3C as Side B, when the beam steering device 127 translates along the “X” axis. Accordingly, by varying the location of the illumination light IL via the beam steering device 127 along the “X” axis, it is possible to illuminate opposite sides of the same sample 180. As a result, an emitted sample signal from each side may be received at the image forming device 195 illustrated in FIGS. 1A-1C, and a composite image of the sample 180 may be formed based on the images of the two sides thereof. FIG. 3C illustrates operation of the beam steering device 127 by a movement of a mirror along a longitudinal direction, such as the “X” axis illustrated in FIGS. 3A and 3B. However, other beam steering techniques may be used withing the scope of this disclosure.

[0051] Composite images can be formed in a variety of ways. In general, a 3D composite can be created by tomography, or by compiling multiple images in a stack that are slices of a three-dimensional structure along one dimension. For example, the composite can be a series of stacked slices of an image in the Z direction (that is, the direction from the sample towards the objective. In various embodiments, one or more images at a first location and one or more images at a second location are formed as described herein. The first location can be a first side of the sample while the second location can be the opposite side of the sample. One or more images are acquired that can be at either different positions in the X-Y plane, or at different positions on the Z axis (that is, into and out of the sample). Once these images at the first and second (or more) locations are acquired, they can be combined to form a composite. In an embodiment, a stack of images in the Z direction, made up of “first images” from one side of the sample and “second images” from the other side of the sample, can be combined into a composite to form a 3D image that is a stack of layers along the Z axis.

[0052] FIGS. 4A-4C illustrate examples of a signal redirection module 172C, in accordance with examples of the disclosure. FIG. 4A illustrate a single reflection configuration, where the returned sample signal or returned light RL which is emitted from the sample is returned by the signal redirection module 172C which, in this case, directs an unrotated returned light RL therefrom. With reference to FIG. 2, the signal redirection module 172C may be substituted to the mirror 281, and may reflect the returned light RL received from the sample onto the first relay lens 282. In the case illustrated in FIG. 4A, the returned light RL returned onto the first relay lens 282 is unrotated and the signal redirection module 172C effectively acts as a mirror.

[0053] FIG. 4B illustrates another example of the signal redirection module 172C’ which includes a combination of mirrors 171 and which results in a rotated sample signal emanating therefrom. In the case of the signal redirection module 172C’ illustrated in FIG. 4B, the returned light RL is rotated before being directed therethrough to, e.g., the first relay lens 282 illustrated in FIG. 2. Accordingly, when the returned light RL emanates from a first side of the sample 180, the signal redirection module 172C illustrated in FIG. 4A may be used, and when the returned light RL emanates from a second side of the sample 180 that is opposite the first side, then the signal redirection module 172C’ illustrated in FIG. 4B may be used. Alternatively, a steering mirror may be used as illustrated in FIG. 3C, where, as discussed above, the position of the mirror or beam steering device 127 is adjusted based on which side of the sample 180 the signal returned light RL is emitted. Accordingly, when signal redirection modules 172C and 172C’ are used, the modules may be positioned on the light path of the returned light RL depending on which side of the sample 180 is being imaged.

[0054] FIG. 4C illustrates a prism as the signal redirection module 172D. In FIG. 4C, the returned light RL enters the prism 172D from one end, illustrated by the entering arrow, is rotated 180°, and is transmitted through the prism 172D in rotated form at an opposite end. In another configuration, the prism 172D may transmit the returned light RL therethrough without rotating the returned sample signal RL. Accordingly, in operation, when the emitted sample signal received at the prism 172D is from a first side of the sample, then the resulting returned light RL may be transmitted without being rotated, and when the emitted sample signal is from a second side of the sample opposite the first side, then the resulting returned light RL may be rotated by the prism 172D and transmitted as a rotated signal therethrough. The prism 172D may be one of a variety of prisms such as, e.g., a truncated right-angle prism, also referred to as Dove prism, a two air-spaced components prism, also referred to as Pechan prism, or any other prism configuration that may independently transmit a signal therethrough unrotated as well as rotate the returned light RL before transmitting the returned light RL therethrough.

[0055] FIG. 5 is a flowchart illustrating a method of performing SPIM or light sheet imaging, in accordance with various examples of the disclosure. In FIG. 5, the method 500 includes operation 510 which includes generating a light source signal at a light source. With reference to FIGS. 1A-1C, the light source signal may be illumination light IL and the light source may be the laser 110. Method 500 further includes operation 520 which includes directing the generated illumination light source signal to a first location of an objective lens in proximity to the sample via a beam steering device 127. The first location of the objective lens may be, e.g., an off-centered side of the objective lens, which results in the illumination light IL reaching the sample at a first side thereof. With reference to FIGS. 1A-1C, directing the light source signal to the sample includes directing the illumination light IL through the beam steering device 127, the dichroic mirror 125, the mirror 160, the objective lens 170, and optionally the redirection module 172A / 172B / 172C / 172C7172D, to the sample 180. With reference to FIGS. 4A-4C, the signal redirection module 172A / 172B / 172C / 172C7172D may be, e.g., a mirror, a mirror combination, or a prism. The signal redirection module may be located in, e.g., a light sheet imaging module. With respect to FIG. 1 A, the signal redirection module 172A may be located in the focusing module 175. With respect to FIG. IB, the signal redirection module 172B may be located on the light path of the transmission subassembly such as, e.g., on the light path between the beam steering device 127 and the dichroic mirror 125, or alternatively at any location between the fiber selector 120 and the objective 170.

[0056] Subsequently to operation 520, operation 530 includes directing, via a light sheet imaging module located between the objective lens and an image forming device, a sample signal emitted from the first side of the sample to the image forming device in a light sheet imaging mode. The sample signal emitted from the first side may be directed unrotated. With reference to FIGS. 1A-1C, directing the emitted sample signal or returned light RL includes directing the returned light RL from the sample 180 through the objective lens 170, the mirror 160, the dichroic mirror 125, the lenses 140 and 150, the focusing module 175, and the ocular lens 190 to the image forming device 195.

[0057] Operation 540 includes directing the generated light source signal to a second location of the objective lens via the beam steering device. With reference to FIG. 1 A, the beam steering device 127 steers the illumination light IL to a different location of the dichroic mirror 125, which reflects the illumination light IL to a different location, or second side, of the sample 180.

[0058] Operation 550 includes directing, via the light sheet imaging module, the sample signal emitted from the second side of the sample to the image forming device in the light sheet imaging mode, the second side being opposite the first side. Directing the sample signal emitted from the second side of the sample can include routing of the signal through a combination of optical components that include reflective, refractive, and transmissive elements, and may include rotating the sample signal before transmitting the sample signal to the image forming device. Directing the sample signal from the second side may be performed along the same light path as directing the sample from the first side, with the difference that the signal redirection module 172A rotates the signal emanating from the second side of the sample by an angle such as, e.g., 180°. Operations 530 and 550 maybe performed independently of each other, so that directing the sample signal emitted from the first side of the sample and directing the rotated optical signal emitted from the second side of the sample are performed independently.

[0059] Operation 560 includes forming an image of the sample at the image forming device. For example, operation 560 may include forming individual images of the sample corresponding to the first side and the second side, and may include forming a composite image of the first side and the second side of the sample at the image forming device. For example, when the sample is near an obstruction such as, e.g., a wall of the sample holder and only one view is possible, then it may be advantageous to form an image from an unobstructed side of sample holder, and the composite image may only include an image of the unobstructed side.

[0060] FIG. 6 depicts a block diagram of a computing device 600 configured to control, e.g., any of the imaging systems 100A-100C discussed above with respect to FIGS. 1A-1C, as well as components thereof. As such, the computing device 600 may be the controller 102 of an imaging system, or a general-purpose computer coupled to such an imaging system, for performing some or all of the necessary operations. In the context of the computing device 600 being a component of an imaging system, the computing device 600 may be used to perform the various operations described herein, as well as related operations. The computing device 600 may send one or more signals as required to various components so as to, for example, move a sample stage, translate or rotate a beam steering device, move an imaging module (such as focusing module 175) into or out of a path of returned light RL, image a sample, rotate a signal redirection module (e.g., a prism) as required or desired, and so on. In another example, operations 510-560 discussed above in the context of FIG. 5, as well as related operations or suboperations, may be performed automatically under control of, e.g., the computing device 600 discussed herein.

[0061] In the illustrated example, the computing device 600 may include a bus 602 or other communication mechanism of similar function for communicating information, and at least one processing element 604 (collectively referred to as processing element 604) coupled with bus 602 for processing information. As will be appreciated by those skilled in the art, the processing element 604 may include a plurality of processing elements or cores, which may be packaged as a single processor or in a distributed arrangement. Furthermore, a plurality of virtual processing elements 604 may be included in the computing device 600 to provide the control or management operations for, e.g., the imaging systems 100A-100C illustrated above, or for example, for the signal redirection module 172A / 172B / 172C / 172C7172D.

[0062] The computing device 600 may also include one or more volatile memory(ies) 606, which can for example include random access memory(ies) (RAM) or other dynamic memory component(s), coupled to one or more busses 602 for use by the at least one processing element 604. Computing device 600 may further include static, non-volatile memory(ies) 608, such as read only memory (ROM) or other static memory components, coupled to busses 602 for storing information and instructions for use by the at least one processing element 604. A storage component 610, such as a storage disk or storage memory, may be provided for storing information and instructions for use by the at least one processing element 604. As will be appreciated, the computing device 600 may include a distributed storage component 612, such as a networked disk or other storage resource available to the computing device 600.

[0063] The computing device 600 may be coupled to one or more displays 614 for displaying information to a user. Optional user input device(s) 616, such as a keyboard and / or touchscreen, may be coupled to Bus 602 for communicating information and command selections to the at least one processing element 604. An optional cursor control or graphical input device 618, such as a mouse, a trackball or cursor direction keys for communicating graphical user interface information and command selections to the at least one processing element. The computing device 600 may further include an input / output (I / O) component, such as a serial connection, digital connection, network connection, or other input / output component for allowing intercommunication with other computing components and the various components of, e.g., the imaging systems 100A-100C discussed above.

[0064] In various examples, computing device 600 can be connected to one or more other computer systems via a network to form a networked system. Such networks can for example include one or more private networks or public networks, such as the Internet. In the networked system, one or more computer systems can store and serve the data to other computer systems. The one or more computer systems that store and serve the data can be referred to as servers or the cloud in a cloud computing scenario. The one or more computer systems can include one or more web servers, for example. The other computer systems that send and receive data to and from the servers or the cloud can be referred to as client or cloud devices, for example. Various operations of, e.g., imaging systems 100 A- 100C may be supported by operation of the distributed computing systems.

[0065] The computing device 600 may be operative to control operation of the components of the imaging systems 100A-100C through a communication device such as, e.g., communication device 620, and to handle data generated by components of the imaging systems 100A-100C through the processing element 604. In some examples, feedback in the form of an image is provided by the computing device 600 in response to the processing element 604 executing instructions contained in memory 606 or 608 and performing operations on data received from the imaging systems 100A-100C such as, e.g., receiving and directing optical signals and adjusting the positions of relay lenses and other components within an imaging module. Execution of instructions contained in memory 606 and / or 608 by the at least one processing element 604 can render, e.g., the imaging systems 100A-100C to perform methods described herein.

[0066] The term “computer-readable medium” as used herein refers to any media that participates in providing instructions to the processing element 604 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as disk storage 610. Volatile media includes dynamic memory, such as memory 606. Transmission media includes coaxial cables, copper wire, and fiber optics, including the wires that include bus 602. Common forms of computer-readable media or computer program products include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, digital video disc (DVD), a Blu-ray Disc, any other optical medium, a thumb drive, a memory card, a RAM, PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, or any other tangible medium from which a computer can read.

[0067] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to the processing element 604 for execution. For example, the instructions may initially be carried on the magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computing device 600 can receive the data on the telephone line and use an infra-red transmitter to convert the data to an infra-red signal. An infra-red detector coupled to bus 602 can receive the data carried in the infra-red signal and place the data on bus 602. Bus 602 carries the data to memory 606, from which the processing element 604 retrieves and executes the instructions. The instructions received by memory 606 and / or memory 608 may optionally be stored on storage device 610 either before or after execution by the processing element 604.

[0068] In accordance with various examples, instructions operative to be executed by a processing element to perform a method are stored on a computer-readable medium. The computer readable medium can be a device that stores digital information. For example, a computer-readable medium includes a compact disc read-only memory (CD-ROM) as is known in the art for storing software. The computer-readable medium is accessed by a processor suitable for executing instructions configured to be executed.

[0069] This disclosure described some examples of the present technology with reference to the accompanying drawings, in which only some of the possible examples were shown. Other aspects can, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. Rather, these examples were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible examples to those skilled in the art.

[0070] Although specific examples were described herein, the scope of the technology is not limited to those specific examples. One skilled in the art will recognize other examples or improvements that are within the scope of the present technology. Therefore, the specific structure, acts, or media are disclosed only as illustrative examples. Examples according to the technology may also combine elements or components of those that are disclosed in general but not expressly exemplified in combination, unless otherwise stated herein. The scope of the technology is defined by the following claims and any equivalents therein.

Claims

CLAIMS1. An optical subassembly comprising: a light source; an objective lens in proximity to a sample stage configured to hold a sample; a transmission subassembly between the light source and the objective lens, the transmission subassembly comprising an adjustment mechanism configured to adjust a position of a beam steering device proximal to the light source and configured to direct an illumination light beam from the light source to the sample stage , the beam steering device configured to direct the illumination light beam to one of a first location of the objective lens and a second location of the objective lens opposite the first location with respect to a central axis thereof; and an emission subassembly along an optical pathway between the objective lens and an image forming device, the emission subassembly being configured to direct a received light beam from one of a first side of the sample and a second side of the sample to an image forming device via a light sheet imaging module; wherein at least one of the transmission subassembly and the emission subassembly comprises a signal redirection module, wherein in a first configuration of the signal redirection module the received light beam is directed from a first side of the sample unrotated, and wherein in a second configuration the received light beam is directed from a second side of the sample rotated.

2. The optical subassembly of claim 1, wherein the signal redirection module comprises one of a mirror, a mirror combination, a spatial light modulator, and a prism.

3. The optical subassembly of claim 1 or claim 2, wherein the received light beam is rotated at an angle in a range of 90° to 270°.

4. The optical subassembly of claim 3, wherein the received light beam is rotated 180°.

5. The optical subassembly of any one of claims 1-4, wherein when the beam steering device comprises an adjustable mirror: the adjustable mirror is configured to rotate around an axis of rotation thereof by one of a first angle and a second angle different from the first angle;the adjustable mirror at the first angle directs the received light beam to the first location of the objective lens and the resulting received light beam is emitted from the first side of the sample; and the adjustable mirror at the second angle directs the received light beam from the light source at the second location of the objective lens, and the resulting received light beam is emitted from the second side of the sample.

6. The optical subassembly of any one of claims 1-5, wherein: the emission subassembly is configured to direct the received light beam to the image forming device via an imaging module, the imaging module comprising: a first portion configured to receive the reflected light beam along a first axis; and a second portion comprising a plurality of relay lenses and a plurality of relay objectives and configured to receive the received light beam from the first portion along a second axis at one of the relay lenses and to return the received light beam to the first portion from one of the relay objectives; the first portion being further configured to direct the received light beam received from the second portion to the image capture device.

7. The optical subassembly of claim 6, wherein the signal redirection module is located within the first portion so as to receive the received light beam.

8. The optical subassembly of any one of claims 1-7, wherein the signal redirection module is located in the transmission subassembly on a light path of the light source signal between the light source and the objective lens.

9. The optical subassembly of any one of claims 1-8, wherein the signal redirection module is located in the emission subassembly on a light path of the sample signal between the objective lens and the imaging module.

10. The optical subassembly of any one of claims 1-9, wherein the beam steering device comprises one of a mirror, a prism and a spatial light modulator.

11. The optical subassembly of claim 10, wherein the adjustment mechanism is configured to rotate or translate at least one of the mirror, the prism and the spatial light modulator.

12. The optical subassembly of any one of claims 1-11, wherein at least one of the transmission subassembly and the emission subassembly further comprise one or more lenses, one or more objectives, and one or more mirrors.

13. An imaging method for a sample, the method comprising: generating an illumination light beam at a light source; directing the generated illumination light beam to a first location of an objective lens in proximity to the sample via a beam steering device; directing, via a light sheet imaging module located along an optical path between the objective lens and an image forming device, a received light beam emitted from a first side of the sample to the image forming device; directing the generated illumination light beam to a second location of the objective lens via the beam steering device; and directing, via the light sheet imaging module, the received light beam from the second side of the sample to the image forming device in the light sheet imaging mode, the second side being opposite the first side.

14. The method of claim 13, further comprising one of: forming a first image of the first side of the sample in the light sheet mode; forming a second image of the second side of the sample in the light sheet mode; and forming a composite image of the first side and the second side of the sample in the light sheet imaging mode.

15. The method of claim 13 or claim 14, wherein directing the received light beam from the first side of the sample comprises directing the received light beam to the image forming device unrotated.

16. The method of any one of claims 13-15, wherein directing the received light beam from the second side of the sample comprises rotating the sample signal before directing the sample signal to the image forming device.

17. The method of any one of claims 13-16, wherein directing the received light beam from the first side of the sample and directing the rotated received light beam from the second side are performed independently.

18. The method of any one of claims 13-17, wherein directing the received light beam from the first side of the sample and from the second side of the sample comprises directing the sample signal through a signal redirection module.

19. The method of claim 18, wherein the signal redirection module is located in the light sheet imaging module.

20. The method of claim 14, wherein: the first image comprises a plurality of first images taken from a first side of the sample and extending along a direction into the sample; the second image comprises a plurality of second images taken from a second side of the sample and extending along the direction into the sample; and the composite is a three-dimensional stack of images made up of the plurality of first images and the plurality of second images.

Images