Abstract:
The present disclosure provides an imaging optical system. In one aspect, the imaging optical system includes, among other things, a light bending element configured to substantially separate electromagnetic radiation into at least two portions, and configured to redirect the at least two portions of said electromagnetic radiation into substantially different directions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 61/782,823, entitled “PUPIL DIVISION MULTIPLEXED IMAGING SYSTEMS,” filed on Mar. 14, 2013, the entire contents of which are incorporated herein by reference and for all purposes. 
    
    
     BACKGROUND 
     These teachings relate generally to optical relay imagers. 
     There is a need for optical imagers that can combine spatial, spectral, hyperspectral, and polarimetric imaging sensors, that provide multiple images and that are more compact and higher performance than conventional designs. 
     SUMMARY 
     Various embodiments of the present disclosure locate a segmented light redirection device, including but not limited to a prism, resulting in multiple images of the source object. These embodiments provide combinations of spatial, spectral, hyperspectral, and polarimetric imaging capability that are more compact and higher performance than conventional systems. 
     While relay imagers are known in the art, a relay imager that is capable of providing multiple and separated images of the object at a common focus plane can provide the basis for a new class of novel multispectral, polarimetric, hyperspectral, and hyperspectral polarimetric imagers. By introducing a segmented element substantially located near the collimated region or pupil of the relay imager, it can be used to form multiple images of the source object at the detector. This makes multiple relay imaging systems of the present disclosure more compact than conventional designs, while providing superior spatial and spectral image quality. 
     Certain characteristics of the present disclosure provide a relay imager design that provides multiple images of the object. 
     Further characteristics of the present disclosure provide a relay imager design that provides high spatial co-registration of the multiple images. 
     Further characteristics of the present disclosure provide a relay imager design that is compact in physical size. 
     Further characteristics of the present disclosure provide a relay imager design that is low in mass. 
     Further characteristics of the present disclosure provide a relay imager design that provides multiple spectral images of the object. 
     Further characteristics of the present disclosure provide a relay imager design that provides multiple polarized images of the object. 
     Further characteristics of the present disclosure provide a relay imager design that provides multiple dispersed images of the object. 
     Further characteristics of the present disclosure provide a relay imager design that provides multiple polarized dispersed images of the object. 
     Further characteristics of the present disclosure provide a hyperspectral imager design that has a high degree of spatial and spectral image quality. 
     Further characteristics of the present disclosure provide a hyperspectral imager design that has low spatial and spectral image distortions. 
     Further characteristics of the present disclosure provide a relay imager design that provides the user with the capability to readily change its spatial, spectral, and polarimetric characteristics. 
     Still further characteristics of the present disclosure provide a relay design that has a combination of the characteristics described above with superior trade-offs than have been previously attainable. 
     For a better understanding of the present disclosure, together with other and further characteristics thereof, reference is made to the accompanying drawings and detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a conventional refractive relay imaging system, taken along its optical axis; 
         FIG. 2  is a schematic view of an optical imaging system taken along its optical axis, in accordance with an embodiment of the present disclosure; 
         FIGS. 3A-3C  are schematic views of the optical imaging system illustrated in  FIG. 2 , taken along its optical axis, in accordance with an embodiment of the present disclosure; 
         FIGS. 4A-4B  are isometric cutaway views of the optical imaging system illustrated in  FIG. 2 , in accordance with an embodiment of the present disclosure; 
         FIG. 5  is a mechanical drawing of the segmented prism component of the optical imaging system illustrated in  FIG. 2 , in accordance with an embodiment of the present disclosure; 
         FIG. 6A  is a schematic view of an optical imager, taken along its optical axis, in accordance with an embodiment of the present disclosure; 
         FIG. 6B  is a schematic view of the optical imager illustrated in  FIG. 6A  with the optical imaging system illustrated in  FIG. 2  optically disposed between the image plane of the imaging lens and the detector, taken along its optical axis, in accordance with an embodiment of the present disclosure; 
         FIG. 7  is a schematic view of a multispectral imager of an optical imaging system, taken along its optical axis, in accordance with an embodiment of the present disclosure; 
         FIG. 8  is a schematic view of an optical imaging system taken along its optical axis, in accordance with another embodiment of the present disclosure; 
         FIG. 9  is a schematic view of a conventional compact refractive relay spectrometer, taken along its optical axis in the plane parallel to the direction of dispersion; 
         FIG. 10  is a schematic view of a hyperspectral imager of an optical imaging system, taken along its optical axis in the plane parallel to the direction of dispersion, in accordance with another embodiment of the present disclosure; 
         FIG. 11  is a schematic view of a hyperspectral imager of an optical imaging system, taken along its optical axis in the plane parallel to the direction of dispersion, in accordance with another embodiment of the present disclosure; 
         FIGS. 12A-12C  are schematic views of the optical imaging system illustrated in  FIG. 11 , taken along its optical axis in the plane parallel to the direction of dispersion, in accordance with an embodiment of the present disclosure; 
         FIG. 13  is a schematic view of the optical imaging system illustrated in  FIG. 11 , taken along its optical axis in the plane perpendicular to the direction of dispersion in accordance with an embodiment of the present disclosure; 
         FIG. 14  is a schematic view of an optical imaging system taken along its optical axis in the plane parallel to the direction of dispersion, in accordance with an embodiment of the present disclosure; 
         FIG. 15A  is a schematic view of an optical imaging system taken along its optical axis in the plane parallel to the image segmentation, in accordance with an embodiment of the present disclosure; and 
         FIG. 15B  is a schematic view of the optical imaging system illustrated in  FIG. 15A , taken along its optical axis in the plane perpendicular to the image segmentation, in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of optical relay imagers that include, but not limited to, combinations of spatial, spectral, hyperspectral, and polarimetric imaging sensors, that provide multiple images and that are more compact and higher performance than conventional designs are disclosed hereinbelow. 
     Reference is made to  FIG. 1 , which is a schematic view of a conventional relay imaging system  100 . Electromagnetic radiation (typically in the ultraviolet, visible, and/or infrared bands, hereinafter referred to generally as light) emitted or reflected by a given object (either real or virtual, hereinafter referred to generally as the source) located at the object plane  20  is re-imaged to a focus position (hereinafter also referred to as an image plane), such as but not limited to a CCD array, phosphorescent screen, photographic film, microbolometer array, or other means of detecting light energy (hereinafter referred to generally as a detector  30 ) through an optical system  40  comprising either refractive or reflective elements, or combination thereof. 
       FIG. 2  illustrates a schematic view of optical imaging system  200 , taken along its optical axis, in accordance with an embodiment of the present disclosure. As shown in  FIG. 2 , optical imaging system  200  includes a segmented light bending element  250 , such as but not limited to a segmented prism, being inserted in a substantially collimated region of an imaging relay lens  240 . In this embodiment, the imaging relay lens  240  of optical imaging system  200  has a magnification of about 0.5, but in principle it can have unity or any other magnification, depending on design choices. 
       FIGS. 3A-3C  illustrate imaging characteristics of the optical imaging system  200  as illustrated in  FIG. 2 . Referring now to  FIG. 3A , light emitted or reflected by a source located at the object plane  220  is incident on a first portion  260  of optical imaging system  200 . In this embodiment, first portion  260  of optical imaging system  200  comprises, but is not limited to, a refractive element  262 , which is capable of substantially receiving a portion of the light emanating from the object plane  220  and substantially collimating the light. The light is then incident upon a segmented prism  250 , which is capable of substantially receiving the light from the first portion  260  of the optical imaging system  200  and separating the light into multiple portions. 
     Referring to  FIG. 3B , a first segment  252  of the segmented prism  250  imparts a first change in the direction of propagation of a first portion of the light that is incident upon the first segment  252 . This redirected first portion of the light is then incident on a second portion  270  of the optical imaging system  200 . In this embodiment, second portion  270  comprises, but is not limited to, refractive elements  272 ,  274 ,  276 , and  278 , which is capable of substantially receiving the light from the first segment  252  of the segmented prism  250  and substantially focusing the light to an image plane of a detector  230 . The change in the direction of propagation of the first portion of the light imparted by the first segment  252  of the segmented prism  250  imparts a first shift in the spatial location of the image  232  on the detector  230 . 
     Referring to  FIG. 3C , a second segment  254  of the segmented prism  250  imparts a second change in the direction of propagation of a second portion of the light that is incident upon the second segment  254 . This redirected second portion of the light is then incident on the second portion  270  of the imaging optical system, which is capable of substantially receiving the light from the second segment  254  of the segmented prism  250  and substantially focusing the light to the detector  230 . The change in the direction of propagation of the second portion of the light imparted by the second segment  254  of the segmented prism  250  imparts a second shift in the spatial location of the image  234  on the detector  230 . 
     This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  252 ,  254 ,  256 , and  258  of the segmented prism  250 , resulting in a plurality of images  232 ,  234 ,  236 , and  238  respectively on the detector  230  that are spatially located at substantially different locations on the detector  230 . The redirection properties of the individual segments  252 ,  254 ,  256 , and  258  of the segmented prism  250  can be designed to place the associated images on the detector  230  at predefined locations, such as but not limited to a tiled non-overlapping pattern. The precision to which these images are aligned with one another and can be co-registered is partially driven by the accuracy with which the individual segments of the segmented prism  250  are fabricated with respect to one another. 
       FIGS. 4A-4B  are isometric cutaway views the optical imaging system  200  illustrated in  FIG. 2 , in accordance with an embodiment of the present disclosure. Referring to  FIG. 4A , the isometric cutaway view of optical imaging system  200  is taken from the direction of object plane  220 , illustrating the spatial relationship between the object plane  220 , the segmented prism  250 , and the multiplexed images that are substantially focused onto the detector  230 . Referring to  FIG. 4B , the isometric cutaway view of optical imaging system  200  is taken from the direction of detector  230 , further illustrating the spatial relationship between the object plane  220 , the segmented prism  250 , and the multiplexed images that are substantially focused onto the detector  230 . 
       FIG. 5  illustrates a mechanical drawing and an isometric view of the segmented prism  250  of optical imaging system  200  illustrated in  FIG. 2 , in accordance with an embodiment of the present disclosure. In this embodiment, the segmented prism  250  comprises four segments  252 ,  254 ,  256 , and  258 , each occupying one quadrant of the aperture and having a faceted surface. In practice, this surface can have any number of mechanical or optical properties such as but not limited to optical power, diffractive surfaces, spectral or polarization filters, etc., provided that the surface imparts a change in the direction of the light incident upon it relative to the light incident upon the other segments. 
     Reference is made to  FIG. 6A , which is a schematic view of a imaging system  300 , in accordance with an embodiment of the present disclosure, despite that the working principles of which may be known in the art. Light, emitted or reflected by a source, is imaged to the image plane  330  through an optical imaging system  320 , in this embodiment comprising, but not limited to, refractive or reflective elements or combination thereof. 
     By selecting the magnification of the imaging relay lens  240  of optical imaging system  200  illustrated in  FIG. 2  such that the physical size of the combined array of segmented images on the detector  230  is substantially the same size as the object plane  220 , the optical imaging system  200  can be designed such that it can be optically disposed to substantially receive a portion of the light from an optical imaging system to add multiplexed image capability to the combined optical imaging system not available in the original imaging system itself. 
     Referring to  FIG. 6B , there is illustrated a schematic view of an optical imaging system  400  including the optical imager  300  of  FIG. 6A  in combination with the optical imaging system  200  of  FIG. 2  optically disposed between image plane  330  of imaging lens  320  and detector  430 , taken along its optical axis, in accordance with an embodiment of the present disclosure. In this embodiment, optical imaging system  200  illustrated in  FIG. 2  is optically disposed to substantially receive a portion of the light from the imaging lens  320  of imaging system  300  illustrated in  FIG. 6A , such that the object plane  220  of optical imaging system  200  illustrated in  FIG. 2  is substantially located at the image plane  330  of imaging system  300  illustrated in  FIG. 6A . 
     In operation, light emitted or reflected by a source, is imaged to the image plane  330  through the optical imaging system  320  comprising refractive or reflective elements or combination thereof. The light is incident on an aperture (such as but not limited to a field stop, hereinafter referred to generally as a field stop  420 ), which is capable of substantially receiving light emanating from the optical imaging system  320  and is located substantially at the image plane  330  of the imaging system  300  illustrated in  FIG. 6A . The light is then incident on the imaging relay lens  240  of optical imaging system  200  illustrated in  FIG. 2 , which is capable of substantially receiving the light from the imaging system  300  and substantially reimaging to detector  230  a plurality of images that are spatially located at substantially different locations on the detector  230 . 
       FIG. 7  illustrates a schematic view of a multispectral imager of an optical imaging system  500 , taken along its optical axis, in accordance with an embodiment of the present disclosure. In this embodiment, individual segments of the segmented prism  250  of optical imaging system  200  illustrated in  FIG. 2  is further made up of individual spectral bandpass optical filters on each of the segments  252 ,  254 ,  256 , and  258  on the segmented prism  250 , such that the individual images  532 ,  534 ,  536 , and  538  on the detector  230  have different spectral content, as illustrated in the schematic view of  FIG. 7 . In this embodiment, the optical imaging system behaves similarly to a multispectral imager that is more compact then conventional designs. In practice, this design can be used to acquire the spectral content of the object in some number of spectral bands. 
     Referring to  FIG. 7 , light emitted or reflected by a source located at the object plane  220  is incident on a first portion  260  of an imaging optical system comprising refractive element  262 , which is capable of substantially receiving a portion of the light emanating from the object plane  220  and substantially collimating the light. The light is then incident upon a segmented prism  550 , which is capable of substantially receiving the light from the first portion  260  of the optical system and separating the light into multiple portions. A first segment  552  of the segmented prism  550 , which is capable of substantially receiving a first spectral portion of the light, imparts a first change in the direction of propagation of the first portion of the light that is incident upon the first segment  552 . This redirected first spectral portion of the light is then incident on a second portion  270  of the imaging optical system comprising refractive elements  272 ,  274 ,  276 , and  278 , which is capable of substantially receiving the first spectral portion of the light from the first segment  552  of the segmented prism  550  and substantially focusing the light to the detector  230 . The change in the direction of propagation of the first spectral portion of the light imparted by the first segment  552  of the segmented prism  550  imparts a first shift in the spatial location of the spectral image  532  on the detector  230 . 
     A second segment  554  of the segmented prism  550 , which is capable of substantially receiving a second spectral portion of the light, imparts a second change in the direction of propagation of the second portion of the light that is incident upon the second segment  554 . This redirected second spectral portion of the light is then incident on the second portion  270  of the imaging optical system, which is capable of substantially receiving the second spectral portion of the light from the second segment  552  of the segmented prism  550  and substantially focusing the light to the detector  230 . The change in the direction of propagation of the second spectral portion of the light imparted by the second segment  554  of the segmented prism  550  imparts a second shift in the spatial location of the image  534  on the detector  230 . This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  552 ,  554 ,  556 , and  558  of the segmented prism  550 , resulting in a plurality of images  532 ,  534 ,  536 , and  538  respectively on the detector  230  that are spatially located at substantially different locations on the detector  230 . 
       FIG. 8  is a schematic view of an optical imaging system  600  taken along its optical axis, in accordance with another embodiment of the present disclosure. In this embodiment, individual segments of the segmented prism  250  of optical imaging system  200  illustrated in  FIG. 2  further comprises individual polarization optical filters on each of the segments  252 ,  254 ,  256 , and  258  on the segmented prism  250 , such that the individual images  632 ,  634 ,  636 , and  638  on the detector  230  have different polarization content, as illustrated in  FIG. 8 . In this embodiment, the optical imaging system  600  behaves similarly to a polarimetric imager that is more compact then conventional designs. In practice, this design can be used to acquire the four Stokes vector components and provide the polarization content of the object. 
     Referring to  FIG. 8 , light emitted or reflected by a source located at the object plane  220  is incident on a first portion  260  of an imaging optical system comprising refractive element  262 , which is capable of substantially receiving a portion of the light emanating from the object plane  220  and substantially collimating the light. The light is then incident upon a segmented prism  650 , which is capable of substantially receiving the light from the first portion  260  of the optical system and separating the light into multiple portions. 
     A first segment  652  of the segmented prism  650 , which is capable of substantially receiving a first polarization portion of the light, imparts a first change in the direction of propagation of the first portion of the light that is incident upon the first segment  652 . This redirected first polarization portion of the light is then incident on a second portion  270  of the imaging optical system, comprising refractive elements  272 ,  274 ,  276 , and  278 , which is capable of substantially receiving the first polarization portion of the light from the first segment  652  of the segmented prism  650  and substantially focusing the light to the detector  230 . The change in the direction of propagation of the first polarization portion of the light imparted by the first segment  652  of the segmented prism  650  imparts a first shift in the spatial location of the polarization image  632  on the detector  230 . 
     A second segment  654  of the segmented prism  650 , which is capable of substantially receiving a second polarization portion of the light, imparts a second change in the direction of propagation of the second portion of the light that is incident upon the second segment  654 . This redirected second polarization portion of the light is then incident on the second portion  270  of the imaging optical system, which is capable of substantially receiving the second polarization portion of the light from the second segment  652  of the segmented prism  650  and substantially focusing the light to the detector  230 . The change in the direction of propagation of the second polarization portion of the light imparted by the second segment  654  of the segmented prism  650  imparts a second shift in the spatial location of the image  634  on the detector  230 . This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  652 ,  654 ,  656 , and  658  of the segmented prism  650 , resulting in a plurality of images  632 ,  634 ,  636 , and  638  respectively on the detector  230  that are spatially located at substantially different locations on the detector  230 . 
     Reference is made to  FIG. 9 , which is a schematic sectional view of a refractive relay spectrometer  700 , taken along its optical axis  710  in the plane parallel to the direction of dispersion. See, for example, U.S. Pat. No. 7,061,611, which is incorporated here by reference in its entirety for all purposes. In operation, light emitted or reflected by a source located substantially at a slit element  720 , is incident on a first portion  730  of the optical system, which is capable of substantially receiving a portion of the light emanating from the slit  720  and substantially collimating the light. The light is then incident on a dispersing element or group of elements  740 , comprising a pair of transmission diffraction gratings (or any means of angularly separating light energy according to its wavelength, hereinafter referred to generally as a dispersing element), which is capable of substantially receiving the light from the first portion  730  of the optical system and dispersing it according to its wavelength. The dispersed light is then incident on a second portion  750  of the optical system, which is capable of substantially receiving the light from the dispersing element  740  and substantially focusing the light to a detecting element  760 . 
       FIG. 10  is a schematic view of a hyperspectral imager of an optical imaging system  800 , taken along its optical axis in the plane parallel to the direction of dispersion, in accordance with another embodiment of the present disclosure. In this embodiment, a segmented light bending element  850 , such as but not limited to a segmented prism, is inserted in a substantially collimated region of a refractive relay spectrometer  840 , as illustrated in  FIG. 10 , taken along its optical axis  810  in the plane parallel to the direction of dispersion. In this embodiment, the refractive relay spectrometer  840  has a magnification of 0.5. It is appreciated, however, that refractive relay spectrometer  840  can have a magnification of unity or any other desired magnification. It is further appreciated that the segmented light bending element  850  can be optically disposed either before or after the dispersing element of the spectrometer  840 . 
     Referring to  FIG. 10 , light emitted or reflected by a source located substantially at a slit element  820  is incident on a first portion  860  of an imaging optical system comprising refractive element  862 , which is capable of substantially receiving a portion of the light emanating from the object plane  820  and substantially collimating the light. The light is then incident on a dispersing element  880 , which is capable of substantially receiving the light from the first portion  860  of the imaging optical system and substantially dispersing it according to its wavelength. The light is then incident upon a segmented prism  850 , which is capable of substantially receiving the light from the dispersing element  880  and separating the light into multiple portions. 
     A first segment  852  of the segmented prism  850 , which is capable of substantially receiving a first portion of the light, imparts a first change in the direction of propagation of the first portion of the light that is incident upon the first segment  852 . This redirected first portion of the light is then incident on a second portion  870  of the imaging optical system comprising refractive elements  872 ,  874 ,  876 , and  878 , which is capable of substantially receiving the first portion of the light from the first segment  852  of the segmented prism  850  and substantially focusing the light to the detector  830 . The change in the direction of propagation of the first portion of the light imparted by the first segment  852  of the segmented prism  850  imparts a first shift in the spatial location of the dispersed image  832  on the detector  830 . 
     A second segment  854  of the segmented prism  850 , which is capable of substantially receiving a second portion of the light, imparts a second change in the direction of propagation of the second portion of the light that is incident upon the second segment  854 . This redirected second portion of the light is then incident on the second portion  870  of the imaging optical system, which is capable of substantially receiving the second portion of the light from the second segment  852  of the segmented prism  850  and substantially focusing the light to the detector  830 . The change in the direction of propagation of the second portion of the light imparted by the second segment  854  of the segmented prism  850  imparts a second shift in the spatial location of the dispersed image  834  on the detector  830 . This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  852 ,  854 , or two other segments of the segmented prism  850 , resulting in a plurality of dispersed images  832 ,  834 ,  836 , and  838  respectively on the detector  830  that are spatially located at substantially different locations on the detector  830 . 
       FIG. 11  is a schematic view of a hyperspectral imager of an optical imaging system, taken along its optical axis in the plane parallel to the direction of dispersion, in accordance with another embodiment of the present disclosure. In this embodiment, the segmented prism component  850  and the dispersive element  880  of  FIG. 10  are combined to form a segmented dispersive element  950 . This segmented dispersive element  950  can comprise any combination of refractive, diffractive, prismatic, etc., elements, such as but not limited to prism elements, provided that the individual surfaces impart a change in the direction of the light incident upon it relative to the light incident upon the other segments, and that the light is further angularly separated according to its wavelength. The imaging characteristics of the optical imaging system  900  illustrated in  FIG. 11  are shown in the schematic views of  FIGS. 12A-12C , taken along its optical axis in the plane parallel to the direction of dispersion. 
     Referring to  FIG. 12A , light emitted or reflected by a source located substantially at a slit element  820  is incident on a first portion  860  of an imaging optical system comprising refractive element  862 , which is capable of substantially receiving a portion of the light emanating from the slit element  220  and substantially collimating the light. The light is then incident upon a segmented dispersive element  950 , which is capable of substantially receiving the light from the first portion  860  of the optical system and separating the light into multiple portions and dispersing the light according to its wavelength. 
     Referring to  FIG. 12B , a first segment  952  of the segmented dispersive element  950  imparts a first change in the direction of propagation of a first portion of the light that is incident upon the first segment  952  and disperses the light according to wavelength. This redirected and dispersed first portion of the light is then incident on a second portion  870  of the imaging optical system comprising refractive elements  872 ,  874 ,  876 , and  878 , which is capable of substantially receiving the light from the first segment  952  of the segmented dispersive element  950  and substantially focusing the light to a detector  930 . The change in the direction of propagation of the first portion of the light imparted by the first segment  952  of the segmented dispersive element  950  imparts a first shift in the spatial location of the dispersed image  932  on the detector  930 . 
     Referring to  FIG. 12C , a second segment  954  of the segmented dispersive element  950  imparts a second change in the direction of propagation of a second portion of the light that is incident upon the second segment  954  and disperses the light according to wavelength. This redirected and dispersed second portion of the light is then incident on the second portion  870  of the imaging optical system, which is capable of substantially receiving the light from the second segment  954  of the segmented dispersive element  950  and substantially focusing the light to the detector  930 . The change in the direction of propagation of the second portion of the light imparted by the second segment  954  of the segmented dispersive element  950  imparts a second shift in the spatial location of the dispersed image  934  on the detector  930 . 
     This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  952 ,  954 ,  956 ,  958  of the segmented dispersive element  950 , resulting in a plurality of dispersed images  932 ,  934 ,  936 ,  938  respectively on the detector  930  that are spatially located at substantially different locations on the detector  930 . The redirection properties of the individual segments  952 ,  954 ,  956 ,  958  of the segmented dispersive element  950  can be designed to place the associated images on the detector  930  at predefined locations, such as but not limited to a tiled non-overlapping pattern. The dispersive properties of the individual segments of the segmented dispersive element  950  can be designed to provide dispersed imagery from different portions of the electromagnetic spectrum or different spectral resolutions or different polarizations or any combination of these attributes at the detector  950 . 
     Reference is made to  FIG. 13 , which is a schematic view of the embodiment of the imaging optical system  900  illustrated in  FIG. 11 , taken along its optical axis  910  in the plane perpendicular to the direction of dispersion. Light emitted or reflected by a source located substantially at the slit element  820  is incident on the first portion  860  of the imaging optical system, which is capable of substantially collimating the light. The light is then incident on the segmented dispersive element  950 , which is capable of separating the light into multiple portions. 
     The first segment  952  of the segmented dispersive element  950  imparts a first change in the direction of propagation of a first portion of the light that is incident upon the first segment  952  and disperses the light according to wavelength. This redirected and dispersed first portion of the light is then incident on a second portion  870  of the imaging optical system, which is capable of substantially focusing the light to a detector  930 . 
     The second segment  954  of the segmented dispersive element  950  imparts a second change in the direction of propagation of a second portion of the light that is incident upon the second segment  954  and disperses the light according to wavelength. This redirected and dispersed second portion of the light is then incident on the second portion  870  of the imaging optical system, which is capable of substantially focusing the light to the detector  930 . 
     This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  952 ,  954 ,  956 , and  958  of the segmented dispersive element  950 , resulting in a plurality of dispersed images  932 ,  934 ,  936 , and  938  respectively on the detector  930  that are spatially located at substantially different locations on the detector  930 . 
       FIG. 14  is a schematic view of the optical imaging system illustrated in  FIG. 11 , taken along its optical axis in the plane parallel to the direction of dispersion in accordance with an embodiment of the present disclosure. In this embodiment, individual segments of the segmented dispersing element  950  of optical imaging system  900  illustrated in  FIG. 11  further comprises individual polarization optical filters on each of the segments  952 ,  954 ,  956 , and  958  on the segmented dispersing element  950 , such that the individual dispersed images  932 ,  934 ,  936 , and  938  on the detector  930  have different polarization content, as illustrated in the schematic view of  FIG. 14 , taken along its optical axis in the plane parallel to the direction of dispersion. In this embodiment, the optical imaging system behaves similarly to a polarimetric hyperspectral imager that is more compact than conventional designs. In practice, this design can be used to acquire the four Stokes vector components and provide the polarization content of the object as a function of wavelength. 
     Referring to  FIG. 14 , light emitted or reflected by a source located substantially at a slit element  820  is incident on a first portion  860  of an imaging optical system comprising refractive element  862 , which is capable of substantially receiving a portion of the light emanating from the object plane  820  and substantially collimating the light. The light is then incident upon a segmented dispersing element  1050 , which is capable of substantially receiving the light from the first portion  860  of the optical system and separating the light into multiple portions and dispersing the light according to its wavelength. 
     A first segment  1052  of the segmented dispersing element  1050 , which is capable of substantially receiving a first polarization portion of the light, imparts a first change in the direction of propagation of the first portion of the light that is incident upon the first segment  1052  and disperses the light according to wavelength. This redirected and dispersed first polarization portion of the light is then incident on a second portion  870  of the imaging optical system comprising refractive elements  872 ,  874 ,  876 , and  878 , which is capable of substantially receiving the first polarization portion of the light from the first segment  1052  of the segmented dispersing element  1050  and substantially focusing the light to the detector  830 . The change in the direction of propagation of the first polarization portion of the light imparted by the first segment  1052  of the segmented dispersing element  1050  imparts a first shift in the spatial location of the dispersed polarization image  1032  on the detector  830 . 
     A second segment  1054  of the segmented dispersing element  1050 , which is capable of substantially receiving a second polarization portion of the light, imparts a second change in the direction of propagation of the second portion of the light that is incident upon the second segment  1054  and disperses the light according to wavelength. This redirected and dispersed second polarization portion of the light is then incident on the second portion  870  of the imaging optical system, which is capable of substantially receiving the second polarization portion of the light from the second segment  1052  of the segmented dispersing element  1050  and substantially focusing the light to the detector  830 . The change in the direction of propagation of the second polarization portion of the light imparted by the second segment  1054  of the segmented dispersing element  1050  imparts a second shift in the spatial location of the dispersed polarization image  1034  on the detector  830 . This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  1052 ,  1054 ,  1056 , and  1058  of the segmented dispersing element  1050 , resulting in a plurality of dispersed polarization images  1032 ,  1034 ,  1036 , and  1038  respectively on the detector  830  that are spatially located at substantially different locations on the detector  830 . 
       FIG. 15A  is a schematic view of an optical imaging system  1100 , taken along its optical axis in the plane parallel to the image segmentation, in accordance with an embodiment of the present disclosure. In this embodiment, light emitted or reflected by a source is incident on an imaging lens  320  comprising refractive or reflective elements or combination thereof, the working principles of which may be known in the art, and substantially focused onto an intermediate image plane, as illustrated in the schematic view of  FIG. 15A , taken along its optical axis  1110 . A field stop  1120  is located substantially at the intermediate image plane, which is capable of substantially receiving a portion of the light emanating from the imaging lens  320 . 
     The light is then incident on a first portion  1160  of an imaging optical system, comprising refractive elements  1162 ,  1164 , and  1166 , which is capable of substantially receiving a portion of the light emanating from the field stop  1120  and substantially collimating the light. The light is then incident upon a segmented light bending element  1150 , such as but not limited to a segmented prism, which is capable of substantially receiving the light from the first portion  1160  of the optical system and separating the light into multiple portions. 
     A first segment  1152  of the segmented prism  1150 , which is capable of substantially receiving a first portion of the light, imparts a first change in the direction of propagation of the first portion of the light that is incident upon the first segment  1152 . This redirected first portion of the light is then incident on a second portion  1170  of the imaging optical system comprising refractive elements  1172 ,  1174 , and  1176 , which is capable of substantially receiving the first portion of the light from the first segment  1152  of the segmented prism  1150  and substantially focusing the light to the detector  1130 . The change in the direction of propagation of the first portion of the light imparted by the first segment  1152  of the segmented prism  1150  imparts a first shift in the spatial location of the image  1132  on the detector  1130 . 
     A second segment  1154  of the segmented prism  1150 , which is capable of substantially receiving a second portion of the light, imparts a second change in the direction of propagation of the second portion of the light that is incident upon the second segment  1154 . This redirected second portion of the light is then incident on the second portion  1170  of the imaging optical system, which is capable of substantially receiving the second portion of the light from the second segment  1152  of the segmented prism  1150  and substantially focusing the light to the detector  1130 . The change in the direction of propagation of the second portion of the light imparted by the second segment  1154  of the segmented prism  1150  imparts a second shift in the spatial location of the image  1134  on the detector  1130 . 
     This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  1152 ,  1154 , and  1156  of the segmented prism  1150 , resulting in a plurality of images  1132 ,  1134 , and  1136  respectively on the detector  1130  that are spatially located at substantially different locations on the detector  1130 . In this embodiment, the segmented prism  1150  is divided into a linear sequence of three segments  1152 ,  1154 , and  1156 , but in practice the number and orientation of segments can be of any configuration desired. 
     Reference is made to  FIG. 15B , which is a schematic view of imaging optical system  1100  illustrated in  FIG. 15A , taken along its optical axis  1110  in the plane perpendicular to the direction of the division of the individual segments  1152 ,  1154 , and  1156  in the segmented prism  1150 . Light emitted or reflected by a source is incident on the imaging lens  320  and substantially focused onto an intermediate image plane. A field stop  1120  is located substantially at the intermediate image plane, which is capable of substantially receiving a portion of the light emanating from the imaging lens  320 . Light is then incident on the first portion  1160  of the imaging optical system, which is capable of substantially collimating the light. The light is then incident on the segmented prism  1150 , which is capable of separating the light into multiple portions. 
     The first segment  1152  of the segmented prism  1150  imparts a first change in the direction of propagation of a first portion of the light that is incident upon the first segment  1152 . This redirected first portion of the light is then incident on a second portion  1170  of the imaging optical system, which is capable of substantially focusing the light to a detector  1130 . 
     The second segment  1154  of the segmented prism  1150  imparts a second change in the direction of propagation of a second portion of the light that is incident upon the second segment  1154 . This redirected second portion of the light is then incident on the second portion  1170  of the imaging optical system, which is capable of substantially focusing the light to the detector  1130 . 
     This reimaging and redirection of the source occurs for the portions of the light that are incident on the segments  1152 ,  1154 , and  1156  of the segmented prism  1150 , resulting in a plurality of dispersed images  1132 ,  1134 , and  1136  respectively on the detector  1130  that are spatially located at substantially different locations on the detector  1130 . 
     The segmented light bending element, particularly when combined with spectral or polarization filters or dispersive surfaces, can be readily interchanged with other segmented light bending elements to provide the user with a degree of modularity not available in conventional imaging systems that allows the imaging characteristics of the pupil division multiplexed imagers of the present disclosure to be easily modified to meet different imaging requirements. 
     As used herein, the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. Except where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” 
     For the purpose of better describing and defining the present disclosure, it is noted that terms of degree (e.g., “substantially,” “about,” and the like) may be used in the specification and/or in the claims. Such terms of degree are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, and/or other representation. The terms of degree may also be utilized herein to represent the degree by which a quantitative representation may vary (e.g., ±10%) from a stated reference without resulting in a change in the basic function of the subject matter at issue. 
     Although embodiments of the present teachings have been described in detail, it is to be understood that such embodiments are described for exemplary and illustrative purposes only. Various changes and/or modifications may be made by those skilled in the relevant art without departing from the spirit and scope of the present disclosure as defined in the appended claims.