Techniques for high resolution and wide format spectrometers

Abstract

Embodiments of the present disclosure relate to a technique for high resolution and wide format spectrometers. In illustrative embodiments, an inverse image slicer converts a linear field of view to a grid shape, allowing the interferometer of a Fourier transform spectrometer to operate over a narrow field of view range, thereby increasing the average spectral resolution of the spectrometer.

Description

Technical Field

[0001] This disclosure relates primarily to the field of spectrometers, and more specifically to techniques for high-resolution and wide-swath spectrometers. Background Technology

[0002] Spectrometers can be used on satellites for various purposes, such as weather forecasting. Fourier transform spectrometers can be used, but these may have poor spectral resolution at wide angles. Moving elements, such as those used in oscillating configurations, can be used to scan a certain range of angles, but this approach increases the cost and complexity of the spectrometer. Summary of the Invention

[0003] According to one aspect of this disclosure, a spectrometer includes: an inverted slicer configured to receive input light destined for the spectrometer; an adjustable interferometer configured to receive light from the inverted slicer; and a sensor configured to sense light from the interferometer; wherein the inverted slicer causes the linear field of view of the spectrometer to be imaged as a two-dimensional grid on the sensor.

[0004] In some embodiments of the spectrometer, the sensor is configured to sense a wavelength range, including 6.2 micrometers.

[0005] In some embodiments of the spectrometer, the sensor includes a two-dimensional pixel array, wherein data from each pixel of the two-dimensional pixel array can be used to determine an imaging resolution better than 2 cm at that pixel. -1 The spectrum.

[0006] In some embodiments of the spectrometer, the inverted slicer converts a field of view that extends across at least 100 milliradians in at least one dimension into a field of view that extends across less than 90 milliradians in each dimension.

[0007] In some embodiments of the spectrometer, the sensor includes a two-dimensional pixel array, wherein each pixel images a field of view between 0.005 milliradians and 30 milliradians.

[0008] In some embodiments of the spectrometer, the inverted slicer includes: a first lens for focusing input light onto a first plurality of mirrors; a first plurality of mirrors, wherein each of the first plurality of mirrors is tilted at an angle different from that of the first plurality of mirrors, wherein each of the first plurality of mirrors is configured to guide light from the first lens to a corresponding mirror of a second plurality of mirrors; a second plurality of mirrors, wherein each of the second plurality of mirrors is configured to guide light from a corresponding mirror of the first plurality of mirrors to a corresponding mirror of a third plurality of mirrors; a third plurality of mirrors, wherein each of the third plurality of mirrors is tilted at an angle different from that of the third plurality of mirrors, wherein each of the third plurality of mirrors is configured to guide light from a corresponding mirror of the second plurality of mirrors to a second lens; and a second lens.

[0009] In some embodiments of the spectrometer, each of the second plurality of mirrors is configured to image the surface of the corresponding mirror of the first plurality of mirrors onto the surface of the corresponding mirror of the second plurality of mirrors.

[0010] In some embodiments of the spectrometer, the interferometer includes a beam splitter, a first mirror, and a second mirror, wherein each of the first and second mirrors is an angle cubic mirror.

[0011] In some embodiments of the spectrometer, the interferometer is configured using a Michelson interferometer.

[0012] According to another aspect of this disclosure, a satellite includes a spectrometer according to any embodiment of the above-described embodiments, including any combination of any or all of the features described above.

[0013] According to another aspect of this disclosure, a method of using a spectrometer includes: focusing light into an inverted slicer configured to receive input light destined for the spectrometer; transmitting light from the inverted slicer to an tunable interferometer; and detecting light from the tunable interferometer at a sensor, wherein the inverted slicer causes the linear field of view of the spectrometer to be imaged as a two-dimensional grid on the sensor.

[0014] In some embodiments, the method may further include: analyzing data from the sensor to determine the spectrum of the gathered light.

[0015] In some embodiments, the method may further include: predicting the weather based on the spectrum of the gathered light.

[0016] In some embodiments of the method, the sensor is configured to sense a wavelength range, including 6.2 micrometers.

[0017] In some embodiments of this method, the sensor includes a two-dimensional pixel array, wherein data from each pixel of the two-dimensional pixel array can be used to determine an imaging resolution better than 2 cm at that pixel. -1 The spectrum.

[0018] In some embodiments of the method, the inverted slicer converts a field of view that extends across at least 100 milliradians in at least one dimension into a field of view that extends across less than 90 milliradians in each dimension.

[0019] In some embodiments of the method, the inverted slicer includes: a first lens for focusing input light onto a first plurality of mirrors; a first plurality of mirrors, wherein each of the first plurality of mirrors is tilted at an angle different from that of the first plurality of mirrors, wherein each of the first plurality of mirrors is configured to guide light from the first lens to a corresponding mirror of a second plurality of mirrors; a second plurality of mirrors, wherein each of the second plurality of mirrors is configured to guide light from a corresponding mirror of the first plurality of mirrors to a corresponding mirror of a third plurality of mirrors; a third plurality of mirrors, wherein each of the third plurality of mirrors is tilted at an angle different from that of the third plurality of mirrors, wherein each of the third plurality of mirrors is configured to guide light from a corresponding mirror of the second plurality of mirrors to a second lens; and a second lens.

[0020] In some embodiments of the method, each of the second plurality of reflectors is configured to image the surface of the corresponding reflector of the first plurality of reflectors onto the surface of the corresponding reflector of the second plurality of reflectors.

[0021] In some embodiments of the method, the interferometer includes a beam splitter, a first mirror, and a second mirror, wherein each of the first and second mirrors is an angle cube mirror.

[0022] In some embodiments of this method, the spectrometer is located on a satellite orbiting the Earth. Attached Figure Description

[0023] The concepts described herein are illustrated in the accompanying drawings by way of example and not limitation. For the sake of simplicity and clarity, the elements illustrated in the drawings are not necessarily drawn to scale. Where deemed appropriate, reference numerals are repeated in the drawings to indicate corresponding or similar elements.

[0024] Figure 1 This is a simplified block diagram of a satellite, including a spectrometer.

[0025] Figure 2 It is in orbit around the Earth. Figure 1 A simplified diagram of at least one embodiment of the satellite;

[0026] Figure 3 yes Figure 1 A simplified diagram of at least one embodiment of an inverted slicer;

[0027] Figure 4 yes Figure 1 A simplified diagram of at least one embodiment of an inverted slicer;

[0028] Figure 5 yes Figure 1 A simplified diagram of at least one embodiment of an inverted slicer;

[0029] Figure 6 yes Figure 1 A simplified diagram of at least one embodiment of the interferometer;

[0030] Figure 7 It has Figure 1 Images of the satellite's field of view; and

[0031] Figure 8 It is by Figure 1 The inverted slicer was rearranged. Figure 1 Images of the satellite's field of view. Detailed Implementation

[0032] While the concepts of this disclosure are readily adaptable to various modifications and alternative implementations, specific embodiments thereof have been illustrated by way of example in the accompanying drawings and described in detail herein. However, it should be understood that this disclosure is not intended to limit the concepts to the specific forms disclosed, but rather, it is intended to cover all modifications, equivalents, and alternatives consistent with the contents of this disclosure and the appended claims.

[0033] References to "an embodiment," "an embodiment," "an illustrative embodiment," etc., in the specification indicate that the described embodiment may include a particular feature, structure, or characteristic; however, each embodiment may or may not include that particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it should be understood that such a feature, structure, or characteristic, relevant to other embodiments, is implemented within the knowledge of those skilled in the art, whether or not it is explicitly described. Additionally, it should be understood that items included in the list in the form of "at least one A, B, and C" may mean (A), (B), (C), (A and B), (B and C), (A and C), or (A, B, and C). Similarly, items listed in the form of "at least one of A, B, or C" may mean (A), (B), (C), (A and B), (B and C), (A and C), or (A, B, and C).

[0034] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored thereon on a transient machine-readable or non-transient machine-readable (e.g., computer-readable) storage medium, which may be read and executed by one or more processors. A machine-readable storage medium may be embodied in any storage device, mechanism, or other physical structure (e.g., volatile or non-volatile memory, media disk, or other media device) for storing or transmitting information in a machine-readable form.

[0035] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Instead, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative figures. Additionally, the inclusion of a structural or methodological feature in a particular figure does not imply that such a feature is required in all embodiments, and in some embodiments, such a feature may not be included or may be combined with other features.

[0036] Now, for reference Figure 1 Satellite 100 includes a spectrometer 102. The spectrometer 102 has a light concentrator 104, an image slicer 106, an interferometer 108, an image sensor 110, and a control circuit system 112. In use, satellite 100 is located in an orbit around the Earth, such as... Figure 2 As shown, spectrometer 102 is configured to monitor the spectrum of the Earth's atmosphere below satellite 100. Spectrometer 102 may have a relatively wide field of view across the orbit of satellite 100 and a relatively narrow field of view along the orbit of satellite 100. As satellite 100 moves across its orbit, the wide transorbital field of view sweeps across the broad area monitored by spectrometer 102. In an illustrative embodiment, spectrometer 102 may be supported in a housing designed to withstand extraterrestrial environments (e.g., an aluminum or stainless steel optical platform and cover).

[0037] Spectrometer 102 uses an inverted slicer 106 to convert the linear field of view of the satellite into a grid, thereby converting the field of view at the light concentrator 104 from, for example, a horizontal field of view of 500 milliradians and a vertical field of view of 20 milliradians to an effective field of view of 100 milliradians by 100 milliradians at the interferometer 108. The field of view of the light concentrator 104 can be any suitable field of view, such as 5 milliradians to 1,500 milliradians along the horizontal and / or vertical directions. It should be understood that labeling a particular field of view as horizontal and / or vertical is arbitrary and does not limit the orientation of the satellite 100, spectrometer 102, or any other component. It should also be understood that the field of view is not necessarily rectangular. For example, the field of view can be elliptical, circular, square, or any other suitable shape. In the illustrative embodiment, the field of view of spectrometer 102 is defined by one or more apertures, pupils, acceptance angles, etc., of one or more components of the light concentrator 104. Additionally or alternatively, the field of view may be defined by another component of the spectrometer, such as an image created on image sensor 110.

[0038] In illustrative embodiments, the light concentrator 104 is a lens combined with an aperture to control the light entering the system. In some embodiments, the light concentrator 104 may be embodied as one or more mirrors, one or more lenses, one or more additional optics, and / or any combination thereof. By way of example, in some embodiments, the light concentrator 104 may include a scanning or statically folding mirror to redirect the line of sight of the spectrometer 102.

[0039] The image inverter slicer 106 can be any suitable image inverter slicer 106 capable of performing the functions described herein. The following section discusses... Figures 3 to 5 An embodiment of the inverted slicer 106 will be described in more detail. However, it should be understood that the inverted slicer 106 can be implemented in different ways. For example, the inverted slicer 106 can be implemented using one or more lenses, prisms, fiber bundles, holograms, or other transmission optics, rather than... Figures 3 to 5 The embodiments described herein are implemented using a mirror-based method. Additionally or alternatively, the image inversion slicer 106 can be implemented using one or more additional components such as a grating, a deformable mirror, adaptive optics, etc. It should be understood that the image inversion slicer 106 operates in a similar manner and utilizes a structure similar to but opposite to that of image slicers known in the art (i.e., where the input and output are interchanged). In the illustrative embodiment, the image inversion slicer 106 divides the field of view into five groups and rearranges them, thereby rearranging the horizontal field of view, which is 25 times the size of the vertical field of view, into an effective field of view that is approximately equal in both the horizontal and vertical directions, as shown below. Figures 3 to 5 As shown. In some embodiments, the inverted slicer 106 can rearrange the field of view into different numbers of groups, such as 2 to 30 groups.

[0040] Interferometer 108 can be any suitable interferometer 108 capable of being used in a Fourier transform spectrometer. The following section discusses... Figure 6 An embodiment of the interferometer 108 based on the Michelson interferometer is described in more detail. In some embodiments, different types of interferometers may be used, such as Fabry-Perot interferometers, Mach-Zehnder interferometers, Sagnac interferometers, static interferometers, slit-based interferometers, etc.

[0041] In the illustrative embodiment, image sensor 110 is a five-by-five pixel two-dimensional (2D) array. Each pixel in the illustrative image sensor 110 corresponds to a field of view of approximately 20 milliradians. In other embodiments, image sensor 110 can be any suitable pixel array, such as an array of 2 pixels to 10,000 pixels by 2 pixels to 10,000 pixels. The field of view per pixel can be any suitable value, such as 0.1 microradians to 100 milliradians. The illustrative image sensor 110 corresponds to a field of view of approximately 600 cm. -1 up to 2900cm -1 Photosensitive light, such as infrared light (i.e., approximately 3.5 to 16.5 micrometers). In the illustrative embodiment, the spectral resolution of the center pixel is 0.76 cm⁻¹ at an 8-micrometer wavelength. -1 Furthermore, the spectral resolution of pixels farther from the axis (i.e., the cornet pixels) is 0.96 cm⁻¹ at a wavelength of 8 micrometers. -1 It should be understood that the spectral resolution can depend on the interferometer 108, discussed in more detail below, and factors such as the wavelength of light. The image sensor 110 can be sensitive to any suitable range of wavelengths, such as any range covering any portion of the UV to far-infrared spectrum (e.g., 300 nanometers to 100 micrometers). In some embodiments, the spectrometer 102 may include more than one sensor 110 sensitive to different wavelength ranges. The image sensor 110 may be embodied as a charge-coupled device (CCD), a complementary metal-oxide-semiconductor device (CMOS), a superconducting camera, or any other suitable light sensor. In some embodiments, the image sensor 110 may use narrow-gap semiconductors such as indium antimonide, indium arsenide, mercury cadmium telluride, lead sulfide, or lead selenide. In illustrative embodiments, the image sensor 110 is actively or passively cooled (e.g., by using a heat sink, Peltier cooler, Stirling engine cryogenic cooler, etc.). In some embodiments, the image sensor 110 may be located on a translation stage.

[0042] Control circuitry system 112 is configured to provide any necessary electrical control, processing, communication, etc., to satellite 100 and / or spectrometer 102. In an illustrative embodiment, control circuitry system 112 receives signals from image sensor 110. Control circuitry system 112 may include a preamplifier and an analog-to-digital converter to convert signals from image sensor 110 into digital signals. Control circuitry system 112 may be configured to control and / or monitor the relative displacement of the two paths of interferometer 108. It should be understood that signals from image sensor 110 do not directly indicate the intensity of a given wavelength. Instead, the output from image sensor 110 takes the form of an interferogram or interference pattern. In an illustrative embodiment, control circuitry system 112 performs necessary analysis to transform the interferogram into a spectrum. Additionally or alternatively, control circuitry system 112 may transmit data from image sensor 110 to a ground station, which may perform analysis to generate a spectrum.

[0043] Here, the control circuitry system 112 can be implemented as any suitable electronic device or collection of devices capable of performing this function. For example, the control circuitry system 112 can be implemented as an application-specific integrated circuit (ASIC), a system-on-a-chip (SoC), a field-programmable gate array (FPGA), a processor-based computer, a multiprocessor system, and / or any other suitable electronic circuitry. In some embodiments, some or all of the control circuitry system 112 can be implemented as processors, memory, and associated components. The processor can be embodied as one or more single-core or multi-core processors, single-socket or multi-socket processors, digital signal processors, microcontrollers, or other processors or processing / control circuitry. Similarly, the memory can be embodied as any type of volatile or non-volatile memory or data storage capable of performing the functions described herein. In operation, the memory can store various data and software used during the operation of the control circuitry system 112, such as operating systems, applications, programs, libraries, and drivers. The control circuitry system 112 may include additional components, such as data storage and communication circuitry. Data storage can be embodied as any type of device or device configured for short-term or long-term storage of data. For example, data storage can include any one or more memory devices and circuitry, memory cards, hard disk drives, solid-state drives, or other data storage devices. The communication circuitry system can be embodied as any type of interface capable of transmitting information to and / or from satellite 100. The communication circuitry system may include or be connected to one or more antennas. The communication circuitry system can be interfaced with any suitable cable type, such as electrical cable or optical cable. The communication circuitry system can be configured to use any one or more communication technologies and associated protocols (e.g., Ethernet, etc.). WiMAX, Near Field Communication (NFC), Omni-Path, etc.). In an illustrative embodiment, conductive sinking is provided to allow control circuitry system 112 (and other electronics of the system) to operate at low voltage.

[0044] Although the illustrative spectrometer 102 is shown located on satellite 100, it should be understood that spectrometer 102 can be used in other embodiments besides satellite 100. For example, spectrometer 102 can be used under an aircraft, mounted on a conveyor belt, or in any instance where the field of view of a pushbroom interferometer is too large for the desired spectral resolution.

[0045] Now, for reference Figures 3 to 5In one embodiment, components of an inverted slicer 106 are shown. A lens 302 focuses incident light. Light from the lens 302 is reflected by a pointing mirror 304 and focused onto a mirror array 306 (i.e., mirrors 306A to 306E). Each mirror in the illustrative array 306A to 306E is concave (to image the aperture of the lens 302 on each mirror in the array 308). In an illustrative embodiment, each mirror in the array 306A to 306E is positioned at approximately one focal length from the lens 302. Each mirror in the array 306A to 306E directs incident light to one mirror in the mirror array 308 (i.e., mirrors 308A to 308E). Specifically, mirror 306A is configured to direct incident light to mirror 308A, mirror 306B is configured to direct incident light to mirror 308B, and so on. Each of the mirrors 308A to 308E refocuses the light and directs it to another array of mirrors 310 (i.e., mirrors 310A to 310E). Specifically, mirror 308A is configured to direct incident light to mirror 310A, mirror 308B is configured to direct incident light to mirror 310B, and so on. Each of the illustrative mirrors 310A to 310E is concave (to image the aperture of lens 302 on lens 312). In the illustrative embodiment, each of the mirrors 308A to 308E is a concave mirror for focusing light. The focal length and placement of each of the mirrors 308A to 308E are such that light focused at the surfaces of mirrors 306A to 306E is also focused at the surfaces of mirrors 310A to 310E. Specifically, in the illustrative embodiment, each of the mirrors 308A to 308E is positioned two focal lengths away from the corresponding mirrors 306A to 306E and 310A to 310E. Each of the mirrors 310A to 310E is configured to reflect incident light toward lens 312. Lens 312 is positioned approximately one focal length away from the mirror array 310 to collimate the light. It should be understood that any light rays incident parallel to the focusing lens 302 are also parallel after passing through lens 312, which is then suitable as the input to an interferometer (see...). Figure 6 It should also be understood that, in the illustrative embodiments, reflectors 306A to 306E, 308A to 308E, and 310A to 310E are configured such that any light ray passing through the center of lens 302 also passes through the center of lens 312. Additionally or alternatively, in some embodiments, the aperture of lens 302 may be imaged on one or both reflectors of interferometer 108, such that any light ray passing through the center of lens 302 is also reflected from the center of one or both reflectors of interferometer 108.

[0046] It should be understood that the linear field of view of the spectrometer 102 is imaged at the mirror array 306. This linear field of view is divided into five groups, which are reassembled from a line at the mirror array 306 into a grid pattern at the mirror array 310.

[0047] Figure 3 Each of the mirrors and lenses shown can be any suitable mirror and lens. For example, lenses 302 and 312 can be, for example, glass, fused silica, silicon, plastic, or any other suitable material. Mirrors 304, 306A to 306E, 308A to 308E, and 310A to 310E can be any suitable type of mirror, such as a substrate coated with, for example, gold, aluminum, silver, copper, interference coating, etc.

[0048] Now, for reference Figure 3 The diagram illustrates the path of a set of rays 314 through the inverted slicer 106. Ray 314 corresponds to three rays originating from the same direction (i.e., from the same point). Ray 314 includes a left ray 314A, a principal ray 314B, and a right ray 314C. All rays 314 are focused on the same point on mirror 306B and guided to mirror 308B. Mirror 308B refocuses the rays 314 and guides them to mirror 310B. Mirror 310B then redirects the rays 314 toward lens 312. It should be understood that mirror 310B guides the principal ray 314B through the center of lens 312. It should also be understood that the rays 314 are horizontally spaced as they pass through lens 302 and also horizontally spaced as they pass through lens 312. Of course, additional rays parallel to ray 314 can be included in use, which are also vertically spaced.

[0049] Now, for reference Figure 4The diagram illustrates the path of a ray set 402 through the image inversion slicer 106. For each of several points in the linear field of view of satellite 100, ray 402 corresponds to a principal ray passing through the center of lens 302 (and lens 312). Specifically, ray 402 includes ray 402A corresponding to the central ray of the first slice of image inversion slicer 106, ray 402B corresponding to the central ray of the second slice of image inversion slicer 106, and so on. Each of rays 402A through 402E is focused onto a corresponding mirror 306A through 306E. Each mirror 306A through 306E directs the corresponding ray 402A through 402E to a corresponding mirror 308A through 308E. Each mirror 308A through 308E directs the corresponding ray 402A through 402E to a corresponding mirror 310A through 310E. Each of the mirrors 310A to 310E guides the corresponding rays 402A to 402E to the center of the lens 312. It should be understood that the rays 402A to 402E initially spread out in different directions along the vertical plane when passing through the lens 302, but are reorganized by the inverted slicer so that they spread out in different directions along the horizontal plane when passing through the lens 312.

[0050] Now, for reference Figure 5 The diagram illustrates the path of a ray set 502 through the inverted slicer 106. For each of several points in the linear field of view of satellite 100 for a single slice of the inverted slicer 106, ray 502 corresponds to a principal ray passing through the center of lens 302 (and lens 312). Specifically, ray 502 includes ray 502A corresponding to the principal ray at the lowest point imaged on mirror 306B, ray 502B corresponding to the principal ray at the center point imaged on mirror 306B, and ray 502C corresponding to the principal ray at the highest point imaged on mirror 306B. Mirror 306B directs rays 502A to 502C to mirror 308B. Mirror 308B directs rays 502A to 502C to mirror 310B. Mirror 310B directs each of rays 502A to 502C to the center of lens 312. It should be understood that when light rays 502A to 502C pass through lens 302, they initially spread out in different directions along the vertical plane, and when they pass through lens 312, they still spread out in different directions along the vertical plane.

[0051] Now, for reference Figure 6 An embodiment of interferometer 108 is shown. The interferometer includes a beam splitter 602, a mirror 604, a mirror 606, and an actuator 608. A lens 610 is also shown, which generates an image on an image sensor 110. The interferometer receives light from lens 312 of the image inverted slicer 106 (see [link to image sensor 110]). Figures 3 to 5The light is split into two paths at beam splitter 602. These two paths are reflected by mirrors 604 and 606 and recombine at beam splitter 602, where the two paths interfere with each other. One of the interference paths is focused onto sensor 110 by lens 610. The other interference path is not used.

[0052] Beam splitter 602 can be embodied as any suitable component for splitting incident light into two or more paths. Beam splitter 602 can be embodied as a cubic beam splitter, a planar beam splitter, a thin-film beam splitter, a polarizing beam splitter, an unpolarizing beam splitter, etc. Beam splitter 602 can be made of any suitable material such as glass, fused silica, silicon, plastic, or any other suitable material. Figure 6 Each of the mirrors and lenses shown can be any suitable mirror and lens. For example, lens 610 can be, for example, glass, fused silica, silicon, plastic, or any other suitable material. Mirrors 604 and 606 can be any suitable type of mirror, such as a substrate coated with, for example, gold, aluminum, silver, copper, interference coating, etc. In the illustrative embodiment, each of mirrors 604 and 606 is embodied as a corner-cube reflector. It should be understood that in this embodiment, interferometer 108 may be less sensitive to rotation from mirrors 604 and 606. Additionally or alternatively, in some embodiments, one or both mirrors 604 and 606 can be plane mirrors.

[0053] It should be understood that the resolution of interferometer 108 can depend on the angle of the incident light. Specifically, light that is almost on the axis may have better spectral resolution, while light that is farther off the axis may have worse spectral resolution. As a result, the transformation of the light at focusing lens 302 from a wide linear field of view to a gridded field of view can improve the average resolution of interferometer 108.

[0054] Actuator 608 is configured to move mirror 606 along the principal axis of light. Mirror 606 may be mounted on a translation stage (not shown) that interfaces with actuator 608. Actuator 608 may be able to move any suitable distance, such as moving closer to or further away from beam splitter 602 relative to the balanced configuration from 0 mm to 10 mm. It should be understood that, in the illustrative embodiment, the optical path difference is twice the offset of mirror 606 relative to the balanced configuration. In other embodiments, the optical path difference may be four times or more the offset of mirror 606 relative to the balanced configuration. In the illustrative embodiment, actuator 608 oscillates back and forth over an optical path difference of ±0.8 cm. In some embodiments, actuator 608 may oscillate over different optical path lengths, such as any suitable distance from a few micrometers to a few meters. The actuator may oscillate over any suitable time period, such as 10 milliseconds to 10 hours. It should be understood that, in the illustrative embodiment, the oscillation center of actuator 608 may deviate from the balanced configuration. For example, actuator 608 can be offset by, for example, the center wavelength of the detected light by a factor of 1 to 10,000. It should be understood that a higher offset can correspond to a higher resolution with a corresponding loss of spectral range.

[0055] Now, for reference Figure 7 and Figure 8 In one embodiment, Figure 7 The image shows a field of view 702. The field of view 702 can be rearranged using an image inversion slicer 106, thereby slicing the field of view into five smaller fields of view 802A to 802E. Fields of view 802A to 802E are arranged to stack on top of each other, such that the image formed on the surface of the sensor is in an approximately square grid shape, as shown below. Figure 8 As shown.

Claims

1. A spectrometer comprising: an inverse image slicer configured to accept input light to the spectrometer; an adjustable interferometer configured to accept light from the inverse image slicer; a sensor configured to sense light from the interferometer; wherein the inverse image slicer causes a linear field of view of the spectrometer to be imaged as a two-dimensional grid on the sensor, wherein the inverse image slicer comprises: a first lens to focus input light onto a first plurality of mirrors; the first plurality of mirrors, wherein each mirror of the first plurality of mirrors is tilted at a different angle from the first plurality of mirrors to each other, wherein each mirror of the first plurality of mirrors is configured to direct light from the first lens to a corresponding mirror of a second plurality of mirrors; the second plurality of mirrors, wherein each mirror of the second plurality of mirrors is configured to direct light from a corresponding mirror of the first plurality of mirrors to a corresponding mirror of a third plurality of mirrors; the third plurality of mirrors, wherein each mirror of the third plurality of mirrors is tilted at a different angle from the third plurality of mirrors to each other, wherein each mirror of the third plurality of mirrors is configured to direct light from a corresponding mirror of the second plurality of mirrors to a second lens; and the second lens.

2. The spectrometer of claim 1, wherein the sensor is configured to sense a range of wavelengths, wherein the range of wavelengths includes 6.2 microns.

3. The optical spectrometer of claim 2, wherein the sensor comprises a two- dimensional pixel array, wherein data from each pixel of the two-dimensional pixel array can be used to determine a resolution better than 2 cm -1 of the spectrum imaged at that pixel.

4. The spectrometer of claim 1, wherein the inverse image slicer converts a field of view extending at least 100 milliradians in at least one dimension to a field of view extending less than 90 milliradians in each dimension.

5. The spectrometer of claim 4, wherein the sensor comprises a two-dimensional array of pixels, wherein each pixel images a field of view between 0.005 milliradians and 30 milliradians.

6. The spectrometer of claim 1, wherein each mirror of the second plurality of mirrors is configured to image a surface of a corresponding mirror of the first plurality of mirrors on a surface of a corresponding mirror of the second plurality of mirrors.

7. The spectrometer of claim 1, wherein the interferometer comprises a beamsplitter, a first mirror, and a second mirror, wherein each of the first mirror and the second mirror is an angle-cube mirror.

8. The spectrometer of claim 1, wherein the interferometer employs a Michelson configuration.

9. A satellite comprising the spectrometer of claim 1.

10. A method of using a spectrometer, the method comprising: gathering light into an inverse image slicer, the inverse image slicer configured to accept input light to the spectrometer; transmitting light from the inverse image slicer to an adjustable interferometer; and detecting light from the adjustable interferometer at a sensor, wherein the inverse image slicer causes a linear field of view of the spectrometer to be imaged as a two-dimensional grid on the sensor, wherein the inverse image slicer comprises: a first lens to focus input light onto a first plurality of mirrors; the first plurality of mirrors, wherein each mirror of the first plurality of mirrors is tilted at a different angle from the first plurality of mirrors to each other, wherein each mirror of the first plurality of mirrors is configured to direct light from the first lens to a corresponding mirror of a second plurality of mirrors; the second plurality of mirrors, wherein each mirror of the second plurality of mirrors is configured to direct light from a corresponding mirror of the first plurality of mirrors to a corresponding mirror of a third plurality of mirrors; the third plurality of mirrors, wherein each mirror of the third plurality of mirrors is tilted at a different angle from the third plurality of mirrors to each other, wherein each mirror of the third plurality of mirrors is configured to direct light from a corresponding mirror of the second plurality of mirrors to a second lens; and the second lens. the first plurality of mirrors, wherein each mirror of the first plurality of mirrors is tilted at a different angle from one another of the first plurality of mirrors, wherein each mirror of the first plurality of mirrors is configured to direct light from the first lens to a corresponding mirror of a second plurality of mirrors; the second plurality of mirrors, wherein each mirror of the second plurality of mirrors is configured to direct light from a corresponding mirror of the first plurality of mirrors to a corresponding mirror of a third plurality of mirrors; the third plurality of mirrors, wherein each mirror of the third plurality of mirrors is tilted at a different angle from one another of the third plurality of mirrors, wherein each mirror of the third plurality of mirrors is configured to direct light from a corresponding mirror of the second plurality of mirrors to a second lens; and the second lens.

11. The method of claim 10, further comprising: analyze data from the sensor to determine a spectrum of the collected light.

12. The method of claim 11, further comprising: predict weather based on the spectrum of the collected light.

13. The method of claim 10, wherein the sensor is configured to sense a range of wavelengths, wherein the range of wavelengths includes 6.2 micrometers.

14. The method of claim 13, wherein the sensor comprises a two-dimensional array of pixels, wherein data from each pixel of the two-dimensional array of pixels can be used to determine a resolution of the imaging at that pixel is better than 2 cm -1 of the spectrum.

15. The method of claim 10, wherein the retroreflector converts a field of view extending at least 100 milliradians in at least one dimension to a field of view extending less than 90 milliradians in each dimension.

16. The method of claim 10, wherein each mirror of the second plurality of mirrors is configured to image a surface of a corresponding mirror of the first plurality of mirrors on a surface of the corresponding mirror of the second plurality of mirrors.

17. The method of claim 10, wherein the interferometer includes a beamsplitter, a first mirror, and a second mirror, wherein each of the first mirror and the second mirror is an angular cube mirror.

18. The method of claim 10, wherein the spectrometer is located on a satellite in orbit around the Earth.

Images