Optical components and systems for synchronized three-dimensional hyperspectral imaging

Abstract

A machined image segmenter compact spectrometer (MICS) for use with a multispectral light source includes a dual-mirror integrating field-of-view unit and a miniature spectrometer array. The integrating field-of-view unit includes: an image segmenter having multiple segmenter mirrors for receiving light from the multispectral light source and outputting multiple diverging beams; and multiple re-imaging mirrors for outputting the image of each segmenter mirror onto an exit slit mask, the exit slit mask containing multiple exit field-of-view stops, each exit field-of-view stop for the image of one segmenter mirror. The miniature spectrometer array includes: multiple optical elements with optical power for receiving light from the multiple exit field-of-view stops; and multiple diffraction gratings with optical power for outputting the image of each segmenter mirror onto an image sensor.

Description

Cross-reference of related applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 616,012, filed December 29, 2023, with the United States Patent and Trademark Office, and U.S. Provisional Application No. 63 / 713,372, filed October 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to optical components and systems for synchronous real-time three-dimensional (two spatial dimensions [x,y] and one spectral dimension [λ]) hyperspectral imaging of a two-dimensional spatial field. Background Technology

[0003] In many commercial and scientific fields, in addition to spatial resolution, cameras used often possess spectral resolution in the red, green, and blue bands that exceeds the range perceptible to the human eye. For these measurements, high-resolution spectral imaging techniques (known as "hyperspectral imaging") have been developed. For example, this hyperspectral imaging can identify and distinguish different chemical elements based on spatially resolved spectra.

[0004] Early hyperspectral imaging systems based on long-slit diffraction gratings (or any dispersive element such as a prism) spectrometers employed a so-called "push-broom" scan, where one dimension of the two-dimensional image sensor was used for spatial determination, while the other dimension was used for spectral determination. New methods in hyperspectral imaging, along with advancements in higher-resolution sensors and computer hardware, have made snapshot-style full-frame hyperspectral systems possible.

[0005] A conventional hyperspectral imager (also known as an integral field spectrograph (IFS)) consists of two parts: (1) an integral field unit (IFU), which reformulates the two-dimensional (2D) spatial field formed by an imaging system such as a telescope, camera lens, or microscope into long, narrow slices or sparsely distributed two-dimensional light source fields; and (2) a conventional grating spectrometer, which is coupled to a two-dimensional sensor to simultaneously record the spectra of all field points. Three types of IFUs (i.e., (1) microlens arrays; (2) coherent fiber arrays; and (3) machined or polished glass image dividers) are commonly used to construct IFSs, each with its own advantages and limitations. The optical systems of spectrometers in conventional IFSs are typically large because they need to support the extended long slits or large sparsely distributed small light sources formed by the IFUs. Due to the large size of the spectrometers, the inherent spectral resolution achievable by these spectrometers (limited by the illumination size of the grating) is usually far greater than the required resolution. Summary of the Invention

[0006] One or more embodiments relate to optical components and systems for performing snapshot-style hyperspectral imaging in a compact structure.

[0007] One or more embodiments relate to a machined image slicer compact spectrograph (MICS) for use with a multispectral light source, the MICS including a dual-mirror integrating field-of-view unit and a miniature spectrometer array. The integrating field-of-view unit includes: an image slicer having multiple slicer mirrors for receiving light from the multispectral light source and outputting multiple diverging beams; and multiple re-imaging mirrors for outputting the image of each slicer mirror onto an exit slit mask containing multiple exit field stops, each exit field stop for the image of one slicer mirror. The miniature spectrometer array includes: multiple optical elements of optical power for receiving light from the multiple exit field stops; and multiple diffraction gratings of optical power for outputting the image of each slicer mirror onto an image sensor.

[0008] Multiple splitter mirrors can be spherical mirrors with variable radii of curvature. Multiple splitter mirrors can also be cylindrical mirrors with variable radii of curvature in the horizontal direction.

[0009] Each of the multiple splitter mirrors can form a miniature pupil between the splitter mirror and the re-imaging mirror.

[0010] Each of the multiple re-imaging mirrors can be an off-axis parabolic re-imaging mirror. Each of the multiple segmenter mirrors forms a miniature pupil at the focal point of the corresponding off-axis parabolic re-imaging mirror. Each of the multiple segmenter mirrors can form a miniature pupil on the corresponding off-axis parabolic re-imaging mirror.

[0011] The MICS can include multiple field lenses positioned at the image of each splitter mirror to condition the beam directed toward the microspectrometer array. The field lenses can have variable curvatures optimized for each beam individually. Alternatively, the field lenses can be biconical lenses with variable curvatures optimized for each beam individually.

[0012] Each of the multiple diffraction gratings with optical power can be a toroidal grating.

[0013] Each of the multiple exit field stops can be an exit slit. Each of the multiple exit field stops can be an exit field lens.

[0014] The dual-mirror integrating field of view unit can be an immersion integrating field of view unit or a free-space integrating field of view unit. The immersion integrating field of view unit can be monolithic and located on a transparent substrate.

[0015] The miniature spectrometer array can be a free-space spectrometer, a transmission spectrometer, or a cross-dispersive spectrometer. In a free-space spectrometer, each of the multiple optical elements with optical power can be a folded mirror. Each of the multiple folded mirrors can be concave in the spectral direction and convex in the spatial direction. Each of the multiple diffraction gratings with optical power is a toroidal grating. Attached Figure Description

[0016] The scope of this disclosure can be best understood from the following detailed description of exemplary embodiments when read in conjunction with the accompanying drawings.

[0017] Figure 1 This is a ray tracing perspective view of an integral field-of-view unit (MISI) for a machining image segmenter according to one embodiment. Figure 2 This is a schematic perspective view of the MISI.

[0018] Figure 3 This is a perspective isometric view of an image slicer according to one embodiment.

[0019] Figure 4 This is a schematic perspective view of a machined image segmenter compact spectrometer (MICS) according to one embodiment. Figure 5 This is a perspective view of a MICS according to one embodiment.

[0020] Figure 6 This is a perspective view of the ray tracing of the principal ray of a single beam from MICS.

[0021] Figures 7 to 9 These are different perspective views of the principal rays for all beams in the MICS.

[0022] Figure 10 This is a schematic side view of MICS for all beams.

[0023] Figure 11 This is a schematic top view of MICS for all beams.

[0024] Figure 12 This is a ray tracing perspective view of a configuration with four MICs according to one embodiment, which share a common optical feed.

[0025] Figure 13This is a schematic perspective view of a configuration having multiple MICs according to one embodiment, each of which has a dedicated optical feed.

[0026] Figure 14 This is a schematic perspective view of a MICS according to one embodiment. Figure 15 yes Figure 14 The MICS ray tracing perspective view for the principal ray of a single beam.

[0027] Figure 16 yes Figure 14 A schematic top view of the MICS. Figure 17 yes Figure 14 The perspective view of the MICS for the principal rays of all beams.

[0028] Figure 18 yes Figure 17 A perspective view of all the beams.

[0029] Figure 19 yes Figure 17 A perspective view of all the beams.

[0030] Figure 20 This is a schematic perspective view of a MICS according to one embodiment.

[0031] Figure 21 yes Figure 20 A schematic perspective top view of the MICS in the diagram.

[0032] Figure 22 yes Figure 20 The MICS in the diagram is a perspective view for all beams.

[0033] Figure 23 This is a perspective view of a transmissive MICS (tMICS) according to one embodiment.

[0034] Figure 24 yes Figure 23 A schematic top view of tMICS.

[0035] Figure 25 yes Figure 23 A perspective view of the transmissive MISI (tMISI) used.

[0036] Figure 26 yes Figure 23 A perspective view of the grating lens array in the image. Detailed Implementation

[0037] An integral field of view unit is an optical device that divides a two-dimensional spatial field into an array or long, narrow slice of two-dimensional image elements (pixels) and uses a re-imaging system to reformat the spatial field into a sparsely distributed point source field or a long slit to form an input source (often called the "incident slit" of a diffraction grating spectrometer) for injection into a diffraction spectrometer coupled with a multispectral light source. like Figure 1 and Figure 2 As shown, the Machined Image Segmenter Integrating Field of View (MISI) 100 includes a machined image segmenter 110, which comprises multiple segmenter mirrors 115, a collimator mirror 120, multiple folding mirrors 130, multiple re-imaging mirrors 140, and an exit field stop or exit slit array (i.e., exit port 150) having multiple corresponding images of the segmenter mirrors 115. These images are then output to a focal plane array 160 at a sensor. Therefore, the re-imaging system of MISI 100 is a four-mirror design: the segmenter mirrors 115, the folding mirrors 130 located between the collimator mirrors 120 and the re-imaging mirrors 140.

[0038] Multiple segmenter mirrors 115 in the image segmenter 110 reflect the incident light beam I into multiple diverging beams B' that are directed toward the collimator mirror 120. The collimator mirror 120 then collimates these diverging beams B' into a collimated beam B and guides the collimated beam B onto a corresponding folding mirror 130. The light output from each folding mirror 130 is reflected and focused by a corresponding re-imaging mirror 140 to image each segmenter mirror 115 onto each exit slit 150 and through that exit slit.

[0039] In particular, each of the miniature splitter mirrors 115 is re-imaged to a designated position in the exit port 150 using collimator mirror 120 (e.g., an off-axis parabolic collimator mirror) to collimate the diverging beam from the splitter mirror 115, which is then refocused onto the focal plane array by corresponding folding mirror 130 (e.g., a miniature planar folding mirror) and re-imaging mirror 140 (e.g., a miniature spherical mirror). Specifically, each re-imaging mirror 140 can be positioned approximately one focal length from the central pupil of each collimated beam B formed by the parabolic collimator mirror 120, effectively making the exit beam telecentric.

[0040] from Figure 3As can be seen, the image segmenter 110 is divided into two segments defined by a ridge 112. The segmenter mirror 115 includes a first plurality of segmenter mirrors 114 and a second plurality of segmenter mirrors 116, divided by the ridge 112. The first plurality of segmenter mirrors 114 have a generally tilted angle to guide the light beam upwards, while the second plurality of segmenter mirrors 116 have a generally tilted angle opposite in direction to the generally tilted angle of the first plurality of segmenter mirrors to guide the light beam downwards. By dividing the image segmenter into two segments, the valley depth of each segment is reduced. Conventional image segmenters (i.e., image segmenters without ridges) must have very deep valleys, making the manufacture of the image segmenter infeasible. However, by including the ridge 112, the valley depth can be reduced. The ridge 112 allows the image segmenter 110 to guide the image from the segmenter mirrors 116 to different folded mirror 130 / re-imaging mirror 140 configurations arranged in an array. The specific design of the image segmenter 110 depends on the arrangement of these other components of the MISI 100 and utilizes the ridge 112 to maintain small angles and the focal plane size of the sensor. In one specific example, image segmenter 110 may include 56 × 2 segmenter mirrors (e.g., each segmenter mirror is 0.036 mm × 2.664 mm in size) to divide the field of view into a total of 112 sub-fields of view (only 6 of them are shown for clarity). The design of image segmenter 110 depends on the downstream configuration and may include additional segments with one or more additional ridges.

[0041] Figures 4 to 11 The image shows a machined image segmenter compact spectrometer (MICS) 200 according to one embodiment. Figure 4 and Figure 6 Relative to the actual configuration (e.g.) Figures 7 to 11 The array (shown in the figure) has been rotated to better showcase its structure. As can be seen in the figure, the MICS 200 employs a machined image segmenter 110 design and the re-imaging system of the MISI 100, but replaces the common collimator mirror 120 with a separate collimator mirror and the folding mirror 130 with a grating. Therefore, the integrating field of view unit of the MISI 100 is transformed into a miniature spectrometer array of the MICS 200. By integrating the grating directly into the integrating field of view unit, the MICS design eliminates the need for a large common spectrometer behind the integrating field of view unit, thus significantly reducing the size of the integrating field of view spectrometer. The optical designs of the MICS according to different configurations—one with a single MICS and another with four MICS—are described below to demonstrate the flexibility and scalability of the design.

[0042] The MICS 200 includes an image segmenter 110, which comprises multiple segmenter mirrors 115, multiple off-axis parabolic mirrors (OAPs) 220, multiple microgratings 230, multiple re-imaging mirrors 140, and a focal plane array 160. Figure 4 As can be seen, the multiple segmenter mirrors 115 in the image segmenter 110 reflect the incident beam I into multiple divergent beams B' directed towards each of the multiple OAPs 220. The OAPs then collimate these beams B' into collimated beams B and guide the collimated beams B onto a corresponding grating 130.

[0043] from Figure 6 As can be seen in the illustration, the micro-grating 230 diffracts each beam in the collimated beam B into multiple component beams λ1 to λn (e.g., white light has three component beams (red, green, and blue)), which are then focused onto the focal plane array 160 as beams Bg. The light output from the micro-grating 230 (here, a reflective grating) is reflected to the focal plane array 160 by the corresponding re-imaging mirror 140. Furthermore, the specific design of the image segmenter 110 will be determined by the arrangement of these other components of the MICS 200 and the focal plane size of the sensor.

[0044] By replacing the folding mirror 130 with the grating 230, each of the four mirrors in the MISI 100 re-imaging system can be converted into a miniature spectrometer. Furthermore, although the MISI 100 re-imaging system has a common parabolic collimator mirror 120 (thus creating a variable reflection angle between the incident and outgoing beams on the folding mirror 130), the MICS 200 employs a separate off-axis parabolic mirror 220, whose parent parabola's vertex is located at the center of the corresponding splitter mirror, to collimate the beam reflected by each of the splitter mirrors 115. This design allows the collimated beam from each of the splitter mirrors 115 to propagate parallel to each corresponding miniature grating 230, maintaining a constant reflection angle (or spectrometer angle) for all miniature spectrometers. Therefore, Figures 4 to 10 The single MICS 200 shown includes a spectrometer array, with each spectrometer serving as a segmenter mirror 115 for the image segmenter 110.

[0045] from Figures 4 to 11 As can be seen in the specific example shown, the image segmenter 110 may include 12×2 segmenter mirrors (e.g., each segmenter mirror is 20μm×0.84mm in size) to form a 4×6 spectrometer array, such as Figure 4 The most clearly shown example is shown below. All miniature spectrometers can have the same grating angle α and spectrometer angle ψ = α. β, where α is the incident angle of the beam of the micrograting 230 relative to the grating normal, and β is the exit angle of the diffracted beam relative to the grating normal. All microgratings can have the same blaze angle. In this specific example, each micrograting can be grouped as part of grating 235, and each grating 235 contains 14 microgratings for the 14 microspectrometers in that row. Furthermore, as can be seen from the figure, the individual collimator mirrors 220, the individual gratings 230, and the individual re-imaging mirrors 140 can each be integrated along one direction of the array (here, the row direction).

[0046] The MICS 200 is designed to utilize modern large-area focal plane arrays (FPAs) with high multiplexing capabilities to simultaneously acquire high-quality spectral information across a two-dimensional field of view in a compact space. Given an FPA with specific physical dimensions and pixel format, the instantaneous spatial and spectral sampling size, as well as the hyperspectral field of view (nx, ny, nλ), can be adjusted according to measurement requirements. For example, larger optics can be used to achieve higher spectral resolution. However, this reduces the number of miniature spectrometers that can be accommodated on the sensor and the instantaneous spatial field of view coverage of the IFS. Nevertheless, the compact size of the MICS allows for the use of multiple MICSs in a single instrument, making it easy to double or quadruple the field of view, such as... Figure 12 As shown.

[0047] Figure 12 An exemplary system 300 is shown, comprising four microarrays 200a to 200d fed by a common source (e.g., telescope 10). A 2×2 field-of-view divider 320 divides the telescope focal plane into four subfields, each for one microarray. Figure 12 The illustration shows details of the field-of-view divider 320. Four bilens-folding relay systems direct four sub-fields of view to a corresponding MICS 200a to 200d. In this specific example, the telescope field of view is divided twice, first by the field-of-view divider 320 into four sub-fields of view, and then each sub-field of view is further divided by an image segmenter in the corresponding MICS 200a to 200d. Additional field-of-view dividers and additional MICS can be cascaded as needed. The image segmenter 110 of the MICS is located at the focal point of the telescope 10, either directly or via an optical repeater. Figure 13Another method for increasing the hyperspectral field of view is illustrated, wherein system 400 includes an array of smaller telescopes 20, a corresponding array of MICS 220 for each telescope 20, and a corresponding array of image sensors 30. Each MICS 220 covers a tessellation field of view, and the tessellation fields of all MICS are combined to form an image over the entire field of view. Furthermore, an image segmenter 110 for the MICS is positioned directly or via an optical repeater at the focal point of each telescope 20.

[0048] Alternatively, each MICS 200 in the array may include multiple MICS 200a to 200d and a field divider 320 for each telescope 220, i.e., using Figure 12 System 300 in the middle. Figures 1 to 13 The embodiments thereof are disclosed in U.S. Application No. 18 / 224,594, filed July 21, 2023, the entire contents of which are incorporated herein by reference.

[0049] Figures 14 to 20 Another configuration of the MICS 500 according to one embodiment is shown. As can be seen from the figure, the MICS 500 utilizes a machined image segmenter 510 and a re-imaging mirror array 520 to re-image the segmenter mirrors onto a common focal plane, and utilizes a folded mirror array 530 with optical power to condition the beam for a diffraction grating array 540 with optical power, which forms the spectrum of all segmenter mirrors onto a final focal plane array 560. An exit slit mask 550 includes a plurality of exit field stops 551, each for an image of one segmenter mirror, positioned at the common focal plane of the re-imaging mirror array 520 to provide control of scattered and stray light.

[0050] Therefore, the MICS 500 includes two dual-mirror re-imaging systems: the dual-mirror integrating field of view unit 501 consists of an image segmenter 510, a re-imaging mirror array 520, and an exit slit mask 550; the dual-mirror spectrometer array 502 consists of a folded mirror array 530 with optical power and a diffraction grating array 540 with optical power.

[0051] from Figure 15 and Figure 16As can be seen, multiple segmenter mirrors 511 in the image segmenter 510 reflect the incident beam B into multiple beams B' that are directed towards multiple re-imaging mirrors 521 in the re-imaging mirror array 520. These re-imaging mirrors form the image of the segmenter mirrors on a common focal plane. The exit slit mask 550 consists of multiple exit field stops 551, each for the image of one segmenter mirror, and is positioned at the common focal plane. The exit slit mask 550 provides effective control of scattered and stray light. Additional baffle systems can be implemented upstream and downstream of the exit field stops 550 to isolate the optical path of each microspectrometer, thereby further suppressing the amplitude of scattered and stray light in the system.

[0052] The splitter mirror 511 can be a plane mirror or have optical power. For the double-mirror IFU 501, the splitter mirror is a cylindrical mirror with a variable radius of curvature along its longitudinal direction. For example... Figure 15 As shown, a splitter mirror with optical power forms a miniature pupil (spatial only) of the optical system at approximately the midway point between splitter mirror 511 and re-imaging mirror 521. The curvature of each splitter mirror 511 is variable (e.g., a variable biconical mirror, depending on the distance between splitter mirror 511 and re-imaging mirror 521) to position the miniature pupil at the focal point of the off-axis parabolic re-imaging mirror 521, i.e., at the vertex of the parabolic mirror. In other words, the variable curvature can be optimized for each beam. Thus, the re-imaging mirror 521 conditions the reflected beam B' into a telecentric beam.

[0053] In the dual-mirror spectrometer array 502, the divergent beam B' emitted from the exit field stop 551 of the exit slit mask 550 propagates toward the optically powerful folding mirrors 531 in the folding mirror array 530. These optically powerful folding mirrors then collimate the divergent beam B' into a collimated or partially collimated beam B'' and guide the collimated beam onto the micro-gratings 541. These micro-gratings form the spectrum of each beam on the final common focal plane of the spectrometer 560.

[0054] The dual-reflector IFU 501 can be constructed as a monolithic unit on a transmission optical substrate (such as indium phosphide, calcium fluoride (CAF2), N-BK7 optical glass, or optical plastics such as acrylic), making it an immersion IFU, in which the optical path from the intermediate surface in the incident beam B to the common focal plane at the exit slit mask 550 can be in a medium other than air.

[0055] The dual-mirror spectrometer 502 can be an immersion spectrometer, wherein at least the dispersive element or collimator mirror 530 and the grating array 540 are both immersed in a medium other than air.

[0056] The MICS 500 can be made into an immersion integrating field spectrometer by encapsulating the entire unit in a high-refractive-index liquid, starting from an optical window at the intermediate surface of the incident beam and ending at a second optical window located in front of the final focal plane 560.

[0057] In the dual-mirror spectrometer array, the third mirror M3 (a folding mirror 531 with optical power) conditions the beam, and the fourth mirror M4 is a grating 541 with optical power, which serves as a dual-mirror spectrometer for each splitter beam, such as... Figure 15 , Figure 16 and Figure 19 As shown in detail below. Both M3 and M4 have optical power, and one or both of M3 and M4 can provide dispersion, for example, both can be gratings, to form a cross-dispersion spectrometer. Each of the two mirrors in the re-imaging system can have the same nominal magnification, for example, 1. In other embodiments, the magnification can be substantially not equal to 1. The two mirror spectrometer 502 can have different magnifications in the X and Y directions (spectral direction or horizontal direction, and spatial direction or vertical direction).

[0058] from Figure 15 As can be seen, the micro grating 541 diffracts each line in the (partial) collimated beam B' into a continuous spectrum. Figure 15 The spectrum is represented by multiple component beams λ1 to λn (e.g., white light has three component beams (red, green, and blue)), which are then focused onto the focal plane array 560 as beams Bg. Furthermore, the specific design of the image segmenter 510 will be determined by the arrangement of these other components of the MICS 500 and the focal plane size of the focal plane array 560.

[0059] Figure 20 It shows the relationship with Figure 15A specific embodiment of a similar MICS dual-mirror spectrometer array. The dimensions of the four mirrors (511, 521, 531, and 541) are magnified to clearly show their shapes, and only the principal ray from the field point at the center of the field of view is shown. It can be seen that the splitter mirror 511 is curved along its longitudinal direction; the re-imaging mirror 521 is an off-axis paraboloid. For the unit spectrometer, the folded mirror 531 with optical power is concave in the spectral direction and convex in the spatial direction, such that collimation is achieved only in the spatial direction; the grating 541 is an annular grating with a concave surface in the spectral direction and flat (infinite radius) in the spatial direction. The curved surface of the grating can be an off-axis portion of a cone.

[0060] Figure 21 and Figure 22 Another configuration of the MICS 600 according to one embodiment is shown. As can be seen from the figure, the MICS 600 is a six-mirror configuration. The first part of the MICS 600 consists of mirrors M1, M2', M3', and M4', and substantially corresponds to... Figure 1 The difference between the MISI and the MICS 600 lies in the presence of a collimator mirror 620. The second part of the MICS 600 consists of a dual-mirror spectrometer (i.e., mirrors M5 and M6), and is essentially corresponding to... Figure 19 A narrow slit mask 610 is provided at each image of the image segmenter 110 to control stray light downstream (i.e., between the first and second portions of the MICS 600).

[0061] In particular, the MICS 600 includes an image segmenter 110 (M1), a collimator mirror 620 (M2'), a folding mirror 630 (M3'), a re-imaging or camera mirror 640 (M4'), an exit slit 610, a collimator mirror 650 (M5), and a miniature grating 660 (M6). Mirror 650 can be the same as mirror 640, but used in a rearward orientation.

[0062] Figure 23 and Figure 24An embodiment of an immersion microscopy system (iMICS) 700 is shown. As can be seen from the figure, the iMICS 700 includes an immersion image segmenter unit or immersion MISI (iMISI) 710 and a grating-lens unit or transmission grating-lens array (tGLA) 720 (along with a sensor used as a dual-mirror spectrometer). The iMISI 710 includes an image segmenter 712, a re-imaging mirror array 713, and a micro-field lens array 714, all of which can be fabricated on a monolithic transparent optical substrate, and has an incident surface 711. The tGLA 720 includes a re-imaging microlens array 721 and a micro-grating array 722, which can be fabricated on a monolithic transparent optical substrate. In this configuration, the spectrometer operates in a partially immersive mode. In particular, both the immersion IFU and the transmission grating lens tGLA can be made of any suitable material for the wavelength of interest and can be molded from resin, machined from a bulk monolithic substrate, or fabricated using a combination of molding, machining, and replication. Compared to the previously discussed free-space designs, the use of immersion and transmission designs increases the F / # of the beam in high-refractive-index substrates, resulting in improved optical performance. This design strategy can also be used to increase the number of miniature spectrometers with a fixed focal plane size, or to increase the numerical aperture of the system to improve the measurement signal-to-noise ratio (SNR). Furthermore, once fabrication is complete, the use of transmission designs reduces final alignment issues. Figure 25 and Figure 26 Details of the iMISI 710 and tGLA720 are shown respectively.

[0063] and Figure 16 Similar to the illustrated embodiment 500, light enters the immersion image segmenter unit 710 through the first incident surface 711 and forms an image of the target on the image segmenter 712. The field of view is segmented into smaller, narrower segments by the image segmenter 712 and directed toward the re-imaging mirror M2' in the re-imaging mirror array 713. These fields of view are refocused onto the field lenses on the exit surface of the immersion image segmenter unit 710 and the micro-field lenses 714a (b, c…) of the field stop array 714. Except for the micro-field lenses 714, the surface area of ​​the exit surface is coated with an opaque coating to prevent upstream scattered light from propagating beyond the field lenses and the field stop array 714. The miniature field lens 714a (b, c...) conditions the beam emitted from the image segmenter unit 710 to minimize the beam footprint on the miniature grating lens of the grating-lens unit 720. The grating-lens array unit 720 includes a re-imaging microlens array 721 to focus the image of the splitter mirror located at the exit field lens and the field stop 714 onto the final focal plane 730 of the instrument. The micrograting array 722 includes microgratings 722a (b, c...) that disperse light and form the spectrum of each sub-field on the final focal plane 730. It will be apparent to those skilled in the art that free-space design and immersion / transmission design can be used in various combinations, i.e. Figures 14 to 22 Any IFU design can be with Figure 23 and Figure 24 Used together with the dual-mirror spectrometer, and Figures 14 to 22 Any dual-mirror spectrometer design can be combined with Figure 23 and Figure 24 Used together with IFU design in the process.

[0064] This disclosure is not limited to the embodiments described above, which are merely exemplary. Those skilled in the art will recognize that the disclosed systems and / or methods can be implemented in other specific forms without departing from the spirit or essential characteristics of this disclosure. Therefore, the embodiments disclosed herein are to be considered illustrative rather than restrictive. This disclosure is not exhaustive and should not be construed as limiting the claimed invention to the specific embodiments disclosed. In view of this disclosure, those skilled in the art will understand that modifications and variations can be made in accordance with the above teachings, or modifications and variations can be obtained from the practice of this disclosure.

Claims

1. A machined image segmenter compact spectrometer (MICS) for use with a multispectral light source, comprising: The dual-mirror integrating field of view unit includes: An image segmenter has multiple segmenter mirrors to receive light from the multispectral light source and output multiple diverging beams; Multiple re-imaging mirrors are used to output the image from each segmenter mirror onto the exit slit mask; and An exit slit mask comprising multiple exit field stops, each exit field stop being used for an image of a splitter mirror; and Miniature spectrometer array, including: Multiple optical elements with optical power receive light from the multiple exit field stops; and Multiple diffraction gratings with optical power are used to output the image of each splitter mirror to the image sensor.

2. The MICS of claim 1, wherein the plurality of splitter mirrors are spherical mirrors having a variable radius of curvature.

3. The MICS according to claim 2, wherein the plurality of splitter mirrors are cylindrical mirrors having a variable radius of curvature in the horizontal direction.

4. The MICS of claim 1, wherein each of the plurality of splitter mirrors forms a micro-pupil between the splitter mirror and the re-imaging mirror.

5. The MICS of claim 1, wherein each of the plurality of re-imaging mirrors is an off-axis parabolic re-imaging mirror.

6. The MICS of claim 5, wherein each of the plurality of splitter mirrors forms a micro-pupil at the focal point of the corresponding off-axis parabolic re-imaging mirror in the plurality of off-axis parabolic re-imaging mirrors.

7. The MICS of claim 5, wherein each of the plurality of splitter mirrors forms a micro-pupil on a corresponding off-axis parabolic re-imaging mirror of the plurality of off-axis parabolic re-imaging mirrors.

8. The MICS of claim 1, wherein a plurality of field lenses are positioned at the image of each splitter mirror to condition the beam directed toward the microspectrometer array.

9. The MICS of claim 8, wherein the plurality of field lenses have variable curvature, each curvature being optimized for each beam.

10. The MICS of claim 8, wherein the plurality of field lenses are biconical lenses having variable curvatures optimized for each beam.

11. The MICS according to claim 1, wherein each of the plurality of diffraction gratings having optical power is an annular surface grating.

12. The MICS of claim 1, wherein each of the plurality of exit field stops is an exit slit.

13. The MICS of claim 1, wherein each of the plurality of exit field stops is an exit field lens.

14. The MICS according to claim 1, wherein the dual-mirror integrating field of view unit is an immersion integrating field of view unit.

15. The MICS of claim 14, wherein the immersion integrating field of view unit is monolithic and located on a transparent substrate.

16. The MICS of claim 14, wherein the micro-spectrometer array is a free-space spectrometer.

17. The MICS of claim 16, wherein in the free-space spectrometer, each of the plurality of optical elements having optical power is a folding mirror.

18. The MICS of claim 17, wherein each of the plurality of folding mirrors is concave in the spectral direction and convex in the spatial direction.

19. The MICS of claim 17, wherein each of the plurality of diffraction gratings having optical power is an annular grating.

20. The MICS of claim 14, wherein the micro-spectrometer array is a transmission spectrometer.

21. The MICS according to claim 1, wherein the dual-mirror integrating field of view unit is a free-space integrating field of view unit.

22. The MICS of claim 21, wherein the micro-spectrometer array is a transmission spectrometer.

23. The MICS of claim 21, wherein the micro-spectrometer array is a free-space spectrometer.

24. The MICS of claim 23, wherein in the free-space spectrometer, each of the plurality of optical elements having optical power is a folding mirror.

25. The MICS of claim 24, wherein each of the plurality of folded mirrors is concave in the spectral direction and convex in the spatial direction.

26. The MICS of claim 21, wherein each of the plurality of diffraction gratings having optical power is an annular grating.

Images