Flex-spectrum optical detector

Abstract

To provide an optical device that can detect responses from a sample over a full spectrum with high sensitivity and high resolution.SOLUTION: An optical device 100 includes a separating element 102 to separate an optical signal 160 into a plurality of spectral bands 165a to 165d that are spatially or angularly separated along a band separation direction. Spectral ranges may differ between respective spectral bands of the plurality of spectral bands. The optical device includes a dispersive element 104 comprising a plurality of dispersive regions. One dispersive region of the plurality of dispersive regions disperses spectral components of one spectral band of the plurality of spectral bands along a dispersion direction to form a dispersed spectral band. The optical device includes a plurality of optical elements 106a to 106c. One optical element of the plurality of optical elements manipulates the dispersed spectral band in association with imaging the spectral band onto detector areas 110a to 110c of a detector array 108.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - Reference to Related Applications This patent application claims priority to U.S. Provisional Patent Application No. 63 / 620,080, filed on January 11, 2024, with the title "FLEX SPECTRUM SPECTROMETRY". The disclosure of the prior application is considered a part of this application and is incorporated herein by reference.

[0002] This disclosure generally relates to optical detectors and flex - spectrum optical detectors.

Background Art

[0003] In spectroscopy, conventionally, by dispersing the full - spectrum response, the dispersed spectrum is formed into the shape of a continuous elongated (high width - to - height aspect ratio) beam composed of dispersed spectral bands. Conventionally, the dispersed spectral bands are imaged such that only one spectral band is imaged in a direction perpendicular to the dispersion direction, without any interruption from one end of the beam to the other end, or for any detector pixel position along the dispersion direction, and they are arranged in a "linear" one - dimensional (1D) sequence. When performing spectroscopy, generally, it is desired to detect the response from a sample with high sensitivity and high resolution over a full spectrum (e.g., for a Raman spectrometer, a spectrum range of more than 100 nanometers (nm) in wavelength or more than 3000 inverse centimeters (cm -1 ) in wavenumber).

Summary of the Invention

Means for Solving the Problems

[0004] In one form, an optical device includes a separating element that separates an optical signal into a plurality of spectral bands that are spatially or angularly separated along a band separation direction and have different spectral ranges between each of the plurality of spectral bands; a dispersive element having a plurality of dispersion regions, wherein one of the plurality of dispersion regions forms a dispersed spectral band by dispersing spectral components of one of the plurality of spectral bands along a dispersion direction; a plurality of optical elements, wherein one of the plurality of optical elements operates on the dispersed spectral band in relation to imaging the spectral band on a detector area of a detector array; and a detector array including the detector area.

[0005] In one form, an optical device includes a separating element that separates an optical signal into a plurality of spectral bands that have different spectral ranges and are spatially or angularly separated along a band separation direction, and a plurality of optical elements, wherein one of the plurality of optical elements operates on one of the plurality of spectral bands in relation to imaging the spectral band on a detector area, and a detector array including the detector area.

[0006] In one form, a method includes separating, by a separating element of an optical device, an optical signal into a plurality of spectral bands that have different spectral ranges and are spatially or angularly separated along a band separation direction; forming, by a dispersive element of the optical device, a dispersed spectral band by dispersing spectral components of one of the plurality of spectral bands along a dispersion direction; and operating, by an optical element of the optical device, on the dispersed spectral band in relation to imaging the spectral band on a detector area of a detector array of the optical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0007]

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Embodiments for Carrying Out the Invention

[0008] With reference to the accompanying drawings, the exemplary embodiments are detailed below. The same reference numerals in different drawings may indicate the same or similar elements.

[0009] In spectroscopic analysis, spectrometers have conventionally been designed to provide light in the form of a single, non - split, linear ray by the dispersive element of the spectrometer, encompassing the full spectral range investigated by the spectrometer. The dispersive element disperses the light, and the dispersed light is projected onto the detector of the spectrometer as a continuous, non - split, linear image. Here, the dispersed spectrum conventionally consists of dispersed spectral components that are imaged with only one spectral component in a direction perpendicular to the dispersion direction, forming a continuous, elongated (high width - to - height aspect ratio) beam shape that runs in a "linear" 1D sequence from one end of the beam to the other, or for any detector pixel position along the dispersion direction without any interruption. When performing spectroscopic analysis, generally, it is desirable to detect the response from a sample with high sensitivity and high resolution over a full spectrum (e.g., for a Raman spectrometer, a spectral range greater than 100 nanometers (nm) in wavelength or greater than 3000 inverse centimeters (cm -1 ) in wavenumber). However, it is difficult to actually do this efficiently. For example, if a high - sensitivity, high - resolution detector array over the full spectrum is required, the physical design of the detector needs to incorporate a high width - to - height aspect ratio. This would result in inefficient use of physical space within the spectrometer system. Therefore, it would be advantageous to abandon the 1D shape of the conventional dispersed spectrum, avoid the high aspect ratio of the detector, and accommodate a more typical 2D imaging detector array.

[0010] Furthermore, every dispersed spectrum has two important attributes: spectral range and spectral resolution. These attributes are incompatible with a fixed physical spectral width. That is, for a given spectral range, there is a given spectral resolution. Increasing the resolution increases the spectral width for a fixed spectral range or decreases the spectral range for a fixed spectral width. Such a limitation exists for the 1D spectrum imaged on the detector. When performing spectroscopic analysis, it is generally desirable for the sensitivity and degree of resolution across the entire spectral band within the full spectral response to be substantially the same. On the other hand, many conventional spectroscopic systems are aimed at identifying specific characteristics such that one or more particular spectral bands can provide more useful specific information while another spectral band may provide minimal specific information. In this case, if the sensitivity and resolution are the same across the entire spectral band, the use of the detector can be inappropriate. Therefore, it would be advantageous to increase the sensitivity and resolution of the spectral bands that provide more useful and higher specific information and decrease the sensitivity and resolution of the spectral bands that provide less useful and lower specific information. Similarly, some spectral bands of the full spectrum may provide no useful information at all, and it may be useful not to image such spectral bands on the detector.

[0011] Conventional two-dimensional (2D) techniques may be used to split the full spectrum, in some cases (e.g., via a beam splitter), into multiple beams, each of which contains the full spectral range. Subsequently, different spectral range portions of each beam are imaged onto different detectors. In particular, according to this conventional 2D technique, each beam contains a full spectrum of a portion of the original power, and only a portion of different spectral bands from each beam is imaged onto the detector. This is a waste of power because the original power is split into each full-spectrum beam, and the portion of each beam that is not imaged onto the detector is wasted. Thus, even for a spectral range that is imaged onto a portion of the detector, the spectral range contains only a small portion of the original power. By wasting power, the sensitivity is also reduced. Therefore, it would be advantageous to image as much of the power from the full-spectrum response as possible onto the detector.

[0012] The forms described herein provide techniques and apparatus for measuring a spectral response that can split a full-spectrum response into spectral bands (e.g., sub-spectra of any spectral range, resolution, or dynamic range). While preserving the power of the full-spectrum response, each spectral band can be oriented to a desired physical location on a detector array through dispersion. In other words, the techniques and apparatus described herein are realizable to separate a full-spectrum response into a group of distinct spectral bands (e.g., sub-spectra) with respect to wavelength or wave number with minimal power loss. These spectral bands can then be independently manipulated or repositioned before spectral dispersion and imaging onto a detector (e.g., a 2D detector). The techniques and apparatus described in this specification avoid power loss when splitting the full-spectrum response, remove the constraints on the bandwidth, resolution, and dynamic range of each spectral band, improve the utilization efficiency of the 2D detector, and enable a smaller spectrometer.

[0013] The techniques and apparatus described herein separate the full spectrum of incident light into spectral bands without loss of power (except for power losses caused by the non-ideality of the optical components performing the separation function) and spatially re-arrange (e.g., stack) the spectral bands before sending them to a dispersive element, enabling a relatively smaller spectrometer. Such a design allows for a higher optical resolution per spectral band from the dispersive element and, depending on the design, may allow for a reduction in the size of the dispersive element in the dispersion direction. After dispersion, the dispersed spectral bands are projected and (e.g., stacked and) imaged onto a 2D detector array. Thus, a higher detector resolution is enabled and the utilization efficiency of the active area of the detector array is improved.

[0014] The techniques and apparatus described herein include spectral banding at the front end. This is to divide the full spectral range into a plurality of spectral bands (e.g., sets of adjacent, sequential, or different spectral ranges) before dispersion. In some forms, the spectral bands may not overlap, or may overlap partially (e.g., minimally), or may almost not overlap (e.g., to account for manufacturing redundancy or tolerance when trying to create non-overlapping or adjacent spectral bands). In some forms, a 2D spectral band arrangement can be created by re-arranging the spectral bands in space and stacking them in a non-dispersion direction (e.g., a direction perpendicular to the dispersion direction) on the dispersive element. In some forms, the dispersive element can comprise a plurality of dispersion regions (e.g., each having different dispersion characteristics) that can be mapped to the incident spectral bands. Thus, each dispersion region of the dispersive element can disperse and redirect the incident light independently of the other dispersion regions.

[0015] After dispersion, the spatial arrangement of the dispersed spectral bands may be maintained, or further rearrangement may occur when the dispersed spectral bands are oriented onto the detector array. For example, in some forms, the dispersed spectral bands are arranged in space and may be stacked on a 2D detector array in the band separation direction. The rearrangement of the spectral bands can be done in various ways (e.g., depending on the selected spectral range division and the resolution target). Generally, the number of spectral bands, the spectral range of the spectral bands, and the spectral resolution of the spectral bands can be freely and independently changed and set according to the desired performance goals for a given application (e.g., Raman, time-gated Raman, spatially offset Raman spectroscopy (SORS), or fluorescence, etc.). For example, the spectrum formed by the sum of all spectral bands can be discontinuous (e.g., interrupted by one or more gaps), or can have different spectral resolutions for each sub-spectrum. Additionally or alternatively, the desired dynamic range and sensitivity for the measurement of each spectral band can be freely set independently of other spectral bands by controlling the "height" (e.g., the direction orthogonal to the dispersion direction) that images each spectral band onto the detector. Increasing the detector area illuminated by a particular spectral band does not change the total amount of photons within that spectral band. On the other hand, increasing the detector area increases the dynamic range achievable in that spectral band and increases the saturation limit of the detector for wavelengths within that spectral band. This is because the photons spread over more pixels of the detector. In some forms, one or more spectral bands (e.g., one or more non-interested spectral bands) can be excluded by the techniques and apparatus described herein. For example, one or more spectral bands can be excluded from imaging on the detector during spectral division, dispersion, or spatial or angular rearrangement (e.g., before or after dispersion).

[0016] In particular, the techniques and apparatus described herein enable full-spectrum splitting in a manner different from the above-described conventional 2D techniques. In some forms, the full spectrum is split into spectral bands with different wavelength / wavenumber ranges, and then they are spatially re-arranged such that the plurality of spectral bands (which may cover the full spectrum range and may include substantially all the power of the original spectrum) are stacked in a direction perpendicular to the dispersion direction to form a 2D arrangement. In such an arrangement, a higher resolution can be achieved compared to a 1D arrangement of the same width (i.e., on a 1D detector). By way of comparison, (assuming, for example, that all spectral bands are of the same width and cover the same spectral range,) to achieve the same full spectrum range with an increased resolution in a linear 1D response, a detector with a spectral dispersion dimension increased by a factor equal to the number of spectral bands created is required. Compared to conventional 2D techniques, since the full spectrum is split into individual, (optionally) non-overlapping spectral bands that include substantially all of the power of the full spectrum, the power loss is minimized. This flex-spectrum spectroscopy technique enables the maximum utilization of the active area of the detector, allowing for a rectangular-shaped (e.g., with a low width-to-height ratio) 2D detector array. In some forms, the full spectrum can be spatially re-arranged and separated into individual non-overlapping spectral bands that are aligned and stacked on the active area of a 2D detector array with a low width-to-height ratio.

[0017] With the same physical size as conventional 1D techniques, the techniques and apparatus described herein can achieve higher resolution and / or cover a larger spectral range. Alternatively, the techniques and apparatus described herein can typically achieve the same performance by reducing the width of the detector in the dispersion direction, which is the maximum dimension of the detector typically used in spectroscopic analysis, to a fraction of the physical size of conventional 1D techniques. Dividing the spectrum to reduce the width and then repositioning the divided spectral bands in a direction perpendicular to the dispersion direction (i.e., the band separation direction) to increase the height results in a detector shape that is advantageous in terms of enabling a spectrometer or spectroscopic analysis system of compact size (e.g., volume), or in terms of compatibility with a wider selection of commercially available large pixel count detector arrays (e.g., SPAD arrays). Increasing the height of the detector to cover additional spectral bands results in only a slight increase or no increase in the height of the spectrometer. On the other hand, reducing the width of the detector reduces the angular spread of the dispersed sub-spectra and the width of the detector in its plane, significantly reducing the footprint. As a result of the reduced detector width, the size of the optical and mechanical components within the spectrometer also decreases, resulting in a reduction in the size, weight, and (potentially) power consumption of the spectrometer system.

[0018] As described above, for a given detector width along the dispersion direction, the techniques and apparatus described herein enable a higher resolution and / or a larger spectral range to be covered. There is no longer a fixed or limiting performance attribute of the spectrometer by the detector width. This flexibility is enabled by adding a second dimension to the spectral layout. With the techniques and apparatus described herein, the detection dynamic range and sensitivity can be varied across the full spectral range. By splitting the spectrum, each spectral band can be adjusted to cover any given height (i.e., the number of pixels in the band separation direction) on the active area of the detector. Thus, for example, the detection dynamic range and sensitivity (which increase or decrease according to the height of the spectral components on the active area of the detector) can be modulated across the various spectral bands to reflect the relative importance of the various spectral bands in a spectroscopic measurement target.

[0019] FIG. 1 is a diagram showing an exemplary form of a flexure spectrum photodetector (referred to as optical device 100 in this specification) described in this specification. As shown in FIG. 1, a light source 145 emits light source light 150 (e.g., a laser beam) that is incident on a sample 155. The optical signal 160 emitted from the sample 155 (e.g., an altered transmission signal from the light source 145, or a signal generated by the sample 155 as a result of excitation by the light source light 150) includes spectral information (i.e., spectral response) directed toward the optical device 100. As shown in FIG. 1, the optical device 100 includes a separation element 102, a dispersion element 104, a plurality of optical elements 106 (e.g., including optical element 106a, optical element 106b, and optical element 106c), and a detector array 108 including a set of detector areas 110 (e.g., detector area 110a, detector area 110b, detector area 110c). The upper diagram of FIG. 1 shows an example of a diagram of the optical device 100 along the dispersion direction (i.e., the direction in which the dispersion element 104 disperses the spectral band 165, as described later), and the lower diagram of FIG. 1 shows an example of a diagram of the optical device 100 along the band separation direction (i.e., the direction in which the separation element 102 separates the optical signal 160 into a plurality of spectral bands 165, as described later).

[0020] The separation element 102 includes one or more elements for separating the optical signal 160 into a plurality of spectral bands 165. That is, the separation element 102 comprises one or more elements for splitting (e.g., for each spectral range) and rearranging (e.g., spatially / angulary) the spectral response from the sample 155 into spectrally band regions (e.g., spectral band 165a, spectral band 165b, spectral band 165c, and spectral band 165d) that are spatially and / or angularly rearranged. In some forms, the direction in which the separation element 102 separates the optical signal 160 into a plurality of spectral bands 165 spatially or angularly is referred to as the band separation direction. In some forms, the band separation direction is perpendicular to the dispersion direction (e.g., the direction in which the dispersion element 104 disperses the spectral band 165). Although a band separation direction perpendicular to the dispersion direction can be used for practical purposes, in some forms (e.g., depending on the shape of the detector), shapes in which the band separation direction is not perpendicular to the dispersion direction can also be utilized. In some forms, the separation of the optical signal 160 (e.g., spectral splitting and rearrangement) is performed in a single direction, i.e., the band separation direction. In one example, the separation element 102 can change the angle of the wavelength of the optical signal 160 so as to generate a continuous spatial spectral spread in the band separation direction.

[0021] The separation element 102 can be configured to provide any number of spectral bands having different characteristics (e.g., physical size and orientation in space, spectral range, and / or spectral width). In some forms, the spectral range varies between each of the plurality of spectral bands 165. In some forms, the spectral bands 165 within the plurality of spectral bands 165 may not substantially overlap (e.g., each spectral band 165 covers a substantially different frequency range). Such forms can be utilized, for example, to maximize the spectral range covered by the banding of the optical signal 160 provided by the separation element 102. In some such forms, a given pair of adjacent spectral bands 165 may have a small overlap (e.g., the overlap ranges from about 2% to about 10% maximum). Such overlap can be utilized, for example, to avoid gaps between spectral bands 165 that may result from design or manufacturing non-idealities. Additionally or alternatively, the spectral bands 165 within the plurality of spectral bands 165 may substantially overlap (e.g., an overlap of a frequency range exceeding about 10%) to provide significant spectral redundancy. As an example, depending on the application, the same sub-band spectral range (e.g., an overlap of about 100%) detected by two different detector areas 110 of the detector array 108 may be required (e.g., if the detector characteristics of the two detector areas 110 are different, or if the power of each "identical" spectral band 165 is intentionally made different when incident on each dedicated detector area 110, etc.).

[0022] In one form, the separating element 12 may be configured such that the optical power varies between the spectral bands 165 (e.g., the optical power of a given spectral band 165 is controlled to be different to a desired extent or intentionally different from the optical power of another spectral band 165). Such a form may be utilized, for example, when different detector areas 120 have different input optical power saturation levels (or thresholds) and it is desirable for the different detector areas 120 to operate similarly. As another example, such a form may be utilized when it is desirable to use detector areas 120 at different input power levels to explore the detector areas 120 in different input optical power saturation regions (e.g., multiple spectral bands 165 with different optical powers but the same spectral range may be transmitted to a plurality of nominally identical detector areas 120).

[0023] In one form, the separation element 102 can split the optical signal 160 into spectral bands without power loss (except for power loss caused, for example, by component non-ideality). Note that conventional techniques are based on power splitting rather than spectral separation. In other words, conventional techniques split an optical signal into N (N>1) substantially equal sub-beams, and each sub-beam has one Nth of the power of each spectral band of the full spectrum. In contrast, the separation provided by the separation element 102 separates the optical signal 160 into a plurality of spectral bands 165 that have all of the power from their respective bands and no power from other bands (within a reasonable range of component non-ideality). Thus, the separation provided by the separation element 102 preserves the power corresponding to each spectral band, enables an improvement in throughput, and thus improves the sensitivity of spectroscopic analysis. Further, by preserving the power associated with each spectrum, the measurement speed of spectroscopic analysis can be improved. For example, the SNR of a given detected spectral component (e.g., a Raman peak within a portion of a spectrum) for a given detection time (i.e., photon collection time) is approximately proportional to the square root of the number of detected Raman photons. For a given excitation pulse energy and number of excitation pulses (i.e., detection period), there are significantly more Raman photons reaching the detector within that spectral component. Thus, spectral splitting achieves a higher SNR (compared to power splitting). This means that for the same SNR, the number of pulses required for spectral splitting is reduced, and thus the detection period is shortened, which is equivalent to an improvement in measurement speed.

[0024] The dispersive element 104 includes one or more elements that disperse the spectral components of the spectral band 165 to form the dispersed spectral band 165. That is, the dispersive element 104 includes one or more elements that disperse the spectral band 165 (e.g., spectral bands 165a to 165d), forming a plurality of dispersed spectral bands 165 (e.g., in the example shown in FIG. 1, the dispersed spectral band 165a, the dispersed spectral band 165c, the dispersed spectral band 165d). In some forms, the dispersive element 104 may include one element that can spatially separate the incident light into different spectral components (e.g., wavelengths). For example, the dispersive element 104 may include a diffraction grating, a prism, or any other wavelength dispersive element. In one exemplary form, the spatially separated spectral bands 165 are incident on a diffraction grating having spatially separated portions (which may or may not be continuous), and each portion is designed to operate at the corresponding incident spectral band 165. In some forms, the direction in which the dispersive element 104 disperses the spectral band 165 is referred to as the dispersion direction. In some forms, the dispersive element 104 includes a plurality of dispersion regions (e.g., each dispersing one of a plurality of spectral bands 165). In some forms, the plurality of dispersion regions may be stacked along a band separation direction (e.g., perpendicular to the dispersion direction). In some forms, a given dispersion region of the dispersive element 104 disperses the incident spectral band 165 independently of the dispersion by other dispersion regions of the dispersive element 104. For example, in some forms, the plurality of dispersion regions are monolithically patterned (or mechanically laid) on a single dispersive element 104, and each dispersion region may have a respective (e.g., different) set of dispersion characteristics.

[0025] During operation, the dispersive element 104 serves to physically separate the spectral components that form a given spectral band 165, and the spectral components of the given spectral band 165 emerge from the dispersive element 104 at different angles and positions, thereby forming the dispersed spectral band 165. In some forms, the dispersion region of the dispersive element 104 can operate differently on each spectral band 165 to produce a dispersed spectral band 165 having different optical properties (e.g., physical size and orientation in space, spectral range, spectral width, or spectral resolution, etc.). For example, a given dispersion region of the dispersive element 104 can divide or separate an angularly and spatially continuous spatial spectrum into individual bands. In some forms, the dispersive element 104 can define the spectral range of a given spectral band 165.

[0026] The plurality of optical elements 106 includes one or more elements for manipulating the dispersed spectral band 165 in connection with imaging the spectral band 165 onto the detector area 110 of the detector array 108. In some forms, the plurality of optical elements 106 comprises an imaging subsystem for the spectral band 165 that is imaged onto the detector array 108. In some forms, the plurality of optical elements 106 includes a plurality of elements operable to manipulate the position, size, and / or orientation / direction of the spectral band 165 in order to image one or more spectral bands 165 from the plurality of spectral bands 165 onto the detector array 108 in a particular arrangement (e.g., determined by the size of the detector array 108, and / or performance attributes and / or functional criteria). For example, a given optical element 106 may include one or more of a lens, prism, wedge, mirror, diffraction grating, or bulk optical element, and combinations thereof. In some forms, a given optical element 106 can preserve one or more characteristics of a given spectral band 165 (e.g., spectral range, spectral resolution, detection dynamic range and sensitivity, or physical size or position on the plane of the detector array 108) and image such characteristics onto a particular detector area 110 of the detector array 108. Additionally or alternatively, a given optical element 106 can modify one or more characteristics of a given spectral band 165. For example, the optical element 106 can be designed to fill the width of the detector array 108 so as to provide the highest resolution and / or to determine the height of the detector array 108 used for each spectral band 165 (e.g., to control the dynamic range and sensitivity). In some forms, the plurality of optical elements 106 can serve to arrange the dispersed spectral bands 165 in order to optimize the use of the detector array 108 (e.g., to maximize the area utilized by the detector array 108, to maximize the optical resolution, or to utilize a particular detector area 110 on the detector array 108 for a particular spectral band 165).For example, the plurality of optical elements 106 can expand the spectral bands 165 dispersed according to the width of the detector array 108 and stack each spectral band 165 on the detector area 110 at its respective height on the detector array 108. In some forms, the plurality of optical elements 106 can manipulate (e.g., orient, operate, focus, collimate, converge, or expand, etc.) the dispersed spectral bands 165 such that the images of the spectral bands 165 are stacked along the band separation direction in the plane of the detector area 110. For example, the plurality of optical elements 106 can, in some forms, achieve a spatial rearrangement of the plurality of spectral bands 165 on the plane of the detector area 110. In some forms, one of the plurality of optical elements 106 can manipulate (e.g., expand) the dispersed spectral bands 165 such that the size of the dispersed spectral bands 165 along the dispersion direction matches the size of the detector area 110 along the dispersion direction (e.g., the area of the detector array 108 that images the spectral bands 165). Similarly, in some forms, the optical element 106 can manipulate (e.g., expand) the dispersed spectral bands 165 such that the size of the dispersed spectral bands 165 in the band separation direction matches the size of the detector area 110 along the band separation direction. In this way, the spatial arrangement of the dispersed spectral bands 165 in the detector area 110 can be controlled to make the best use of a particular detector shape (e.g., a rectangular 2D detector array 108).

[0027] The detector array 108 includes one or more detector areas 110 on which one or more spectral bands 165 are imaged. In some forms, as shown in FIG. 1, the detector area 110 may include a plurality of detector areas 110 stacked along the band separation direction. In some forms, the detector array 108 may include a 2D array (e.g., a 2D array of detector areas 110). Additionally or alternatively, the detector array 108 may include a plurality of 1D detector arrays (e.g., a plurality of 1D detector arrays stacked along the band separation direction). According to such forms, for example, the detection capabilities (e.g., spectral range, spectral resolution, detection dynamic range, or detection sensitivity, etc.) of the optical device 100 can be extended. In some forms, the detector array 108 may include a single photon avalanche diode (SPAD) array (e.g., a high dynamic range and sensitivity, high time resolution (sub-nanosecond) SPAD array). Additionally or alternatively, the detector array 108 may include an array of time-resolved photon counting detectors (e.g., an array of areas that can associate a time stamp with each photon detected by a given area). Such detectors may be referred to as time-binned photon counting detectors or time-tagged photon counting detectors. Alternatively, the detector array 118 may include a detector array that includes photon detectors using another type of technology (e.g., an array of photon detectors that may or may not include time-resolved photon counting detectors). In some forms, the size of the first detector area 110 of the plurality of detector areas 110 is different from the size of the second detector area 110 of the plurality of detector areas 110. In some forms, the detector areas 110 of the detector array 108 can be used for a plurality of spectral bands 165. For example, by multiplexing in the time domain in combination with an active element that can select the spectral band 165 that is operated and imaged on a given detector area 110 at a given time, the reuse of the detector area 110 can be made possible.

[0028] In one form, the size of the first detector area 110 of the detector array 108 in the dispersion direction matches the size of the second detector area 110 of the detector array 108 in the dispersion direction, and the size of the first detector area 110 in the band separation direction is different from the size of the second detector area 110 in the band separation direction. In such a form, a greater sensitivity is achieved for the spectral band 165 imaged on the first detector area 110 of relatively large size. Thus, by controlling the "height" in the band separation direction in which each spectral band 165 is imaged on the detector array 108, the desired dynamic range and sensitivity for the measurement of each spectral band 165 can be freely set independently of the other spectral bands 165. Increasing the size of the detector area 110 irradiated by a particular spectral band 165 does not change the total amount of photons within that spectral band 165, but the increase in size improves the dynamic range and sensitivity achievable in that spectral band 165 (e.g., by reducing the effect of the reset "dead time" that occurs after a pixel detection event in an SPAD array), and since the photons spread over more pixels of the detector array 108, the saturation limit of the detector array 108 increases with respect to the wavelength within the spectral band 165.

[0029] In the example shown in FIG. 1, the separation element 102 provides four spectral bands 165 (i.e., four sub-spectra), three of which (e.g., spectral band 165a, spectral band 165c, and spectral band 165d) are directed to the dispersion element 104. They are dispersed thereby and are then manipulated by respective optical elements 106 for imaging in three different shapes (e.g., with different heights of each spectral band 165). Examples of the results of arranging the optical signal 160 in these three spectral bands 165 having different characteristics (e.g., dynamic range and sensitivity depending on height, spectral range, spectral width covered, spectral resolution) are shown in FIG. 1 and Table 1 below. In this example, spectral band 165b is not imaged on the detector array 108. That is, in some forms, at least one spectral band 165 of the plurality of spectral bands 165 may not be imaged on any detector area 110 of the detector array 108. Such a form can be utilized, for example, when it is not necessary to measure or detect a part of the full spectrum (e.g., spectral band 165b). In some forms, the ability to have such a spectral gap in the detection by the detector array 108 can enable enhancement of one or more other attributes of the detected spectral band 165 (e.g., improvement in resolution, redundancy, or readout speed, etc.). Thus, in some forms, the spectrum formed by the combination of the spectral bands 165 imaged on the detector array 108 is discontinuous (e.g., includes one or more spectral gaps). In some forms, the optical power of a given spectral band 165 of the plurality of spectral bands 165 in the detector array 108 exceeds 90% of the optical power of the spectral band 165 before the separation element 102. That is, the spectral band 165 can be imaged on the detector array 108 without power loss or with minimal power loss (excluding power loss caused by non-ideality of the optical components performing the separation function).

[0030] In particular, when imaging onto a detector array 108 (e.g., a 2D detector array), since the spectral bands 165 can be stacked, the angular range required for the elements of the optical device 100 and the optical system is significantly reduced in the dispersion direction (e.g., as compared to conventional devices using a relatively long 1D detector). This reduces the physical size of the optical device 100, enabling miniaturization of the optical engine. Further, the optical device 100 is applicable to many existing spectroscopic techniques. For example, the optical device 100 can be used for Raman and fluorescence spectroscopy, and the readout time of the detector array 108 can be time-gated and / or correlated with the exposure of the sample 155 to the source light 150.

[0031] Furthermore, according to the techniques described herein, in some forms, a given spectral band 165 can be directed to any detector area 110 of the detector array 108. The active area of the detector array 108 need not be the same as the area dimensioned by the sum of the areas of the entire spectral band 165 detected in the plane of the detector array 108. In some forms, the spectral band 165 can be arranged to fit the width of the active area of the detector array 108, and a scanning mechanism can be used to move the spectral band 165 in the band separation direction to reach the detector area 110, or to move the detector array 108 in the band separation direction to enter the field of view of the desired spectral band 165. This can enable measurement of the entire spectrum (e.g., the sum of all spectral bands 165) using a miniaturized detector array 108 (e.g., a miniaturized 1D array or 2D array with a reduced number of detector regions) having a width set to the width of a single spectral band 165.

[0032] In some forms, one or more elements of the optical device 100 can be statically configured (e.g., using a conventional optical system). Additionally or alternatively, for example, one or more elements of the optical device 100 can be dynamically configured such that, for example, the number of spectral bands 165 generated, the spectral range of each spectral band 165, the dynamic range and sensitivity (or height on the detector array 108) applied to each spectral band 165, and / or the position at which each spectral band 165 is imaged onto the detector array 108 can be dynamically configured. The dynamic configuration can enable different spectral bands 165 from different pulses to be imaged onto the detector array 108. In some forms, the readout of one or more detector areas 110 of the detector array 108 can be performed using various techniques, such as using a global shutter or a rolling shutter. Further, in some forms, one or more spectral bands 165 can be removed by the separation element 102 (e.g., as shown in FIG. 1). Additionally or alternatively, one or more other elements of the optical device 10, such as the dispersion element 104 or one or more optical elements 106, can be configured to remove one or more spectral bands 165 (e.g., such that one or more spectral bands 165 are not imaged onto the detector array 108).

[0033] The optical resolution is achieved by the dispersive element 104 (e.g., diffraction grating resolution) regardless of the characteristics of the detector array 108. The detector resolution is achieved by the detector array 108 (e.g., pixel size of the detector array 108) and is similarly independent of the dispersive element 104. The system resolution is a combination of the optical resolution and the detector resolution. The best result achievable with the optical device 100 is the optical resolution. Even if better detector resolution is achieved, the detector array 108 cannot perform sampling at a higher resolution than that achieved by the spectral band 165 dispersed by the dispersive element 104. A realistic goal is to match the detector resolution to the optical resolution so as to avoid a decrease in the optical resolution without involving unnecessary pixels. In some forms, the spectral resolution of the first spectral band 165 among the plurality of spectral bands 165 is different from the spectral resolution of the second spectral band 165 among the plurality of spectral bands 165.

[0034] The spectral range is realized by the range of wavenumbers or wavelengths included within a particular spectral response, signal, band, or sub - spectrum. The spectral range is similar to the bandwidth with respect to wavelength. In the case of Raman spectroscopy, an exemplary spectral range of the optical signal 160 can be greater than about 100 nm (in wavelength) or greater than about 3000 cm−1 (in wavenumber). Further, an exemplary spectral range of a given spectral band 165 can have wavenumbers in the range of about 400 - 700. In some forms, the spectral range of the first spectral band 165 among the plurality of spectral bands 165 can be different from the spectral range of the second spectral band 165 among the plurality of spectral bands 165.

[0035] The dynamic range is the range of values that can be observed from a set of pixels of the detector array 108 for a particular wavelength / wavenumber of the spectral band 165. In some forms, by increasing the number of pixels per wavelength / wavenumber, (e.g., by reducing the effect of the reset “dead time” that occurs after a pixel detection event in a SPAD array), the dynamic range for that wavelength / wavenumber can be increased.

[0036] As described above, FIG. 1 is provided as an example. Other examples may differ from those described with respect to FIG. 1. The number and arrangement of the elements shown in FIG. 1 are provided as an example. In practice, there may be additional elements, fewer elements, different elements, or elements with a different arrangement, compared to those shown in FIG. 1. Further, two or more elements shown in FIG. 1 may be implemented within a single element, or a single element shown in FIG. 1 may be implemented as a plurality of distributed elements. Additionally or alternatively, a set of elements shown in FIG. 1 (e.g., one or more elements) may perform one or more functions as described to be performed by a different set of elements shown in FIG. 1.

[0037] FIG. 2 shows an example related to an optical device 100 that realizes a flexible splitting and arrangement of a full spectrum in combination with Table 1 (below). In the example shown in FIG. 2, the spectral bands 165 are arranged such that the spectral band 165 is imaged stacked in the band separation direction (e.g., a direction perpendicular to the dispersion direction) in the detector array 108. As described above, the spectral bands 165 can be arranged in various ways, for example, according to the spectral range, spectral resolution, and / or detection dynamic range and target sensitivity. In some forms, the number and area of the spectral bands 165 are variable, and the spectral range, resolution, dynamic range, and / or sensitivity of each spectral band 165 can be set independently of those of the other spectral bands 165 (e.g., to achieve the specific performance goals of a given application). For example, in some forms, a portion of the full spectrum that does not need to be measured or detected (e.g., spectral band 165b) can be skipped (e.g., avoided or rejected). As another example, specific pixels or detector areas 110 in the detector array 108 that are not usable or should not be used can be avoided.

[0038] [Table 1]

[0039] Table 1 shows, as shown in FIG. 2, numerical examples showing the attributes of different spectral bands 165 imaged on a 2D detector array 108 including three detector areas 110. In this example, the height of the exemplary detector area 110 is 700 pixels, and the exemplary spectral range (expressed as a spectral shift from the excitation wavelength) is 0 to 1600 wavenumbers. Here, a spectral band 165b as a part of the full spectrum is not imaged on the detector array 108 because it is not measured or monitored. On the other hand, the rest of the full spectrum is divided into a spectral band 165a, a spectral band 165c, and a spectral band 165d. These have different spectral ranges, resolutions, dynamic ranges, and sensitivities (e.g., increasing or decreasing according to the height of the detector array 108 and referred to as band height in Table 1), and are imaged on different detector areas 110 of the detector array 108.

[0040] As described above, FIG. 2 is provided as an example. Other examples may be different from those described with respect to FIG. 2.

[0041] FIGS. 3 and 4 are diagrams related to the improvement of the dynamic range and sensitivity enabled by the optical device 100. In some forms, it is possible to improve the dynamic range and sensitivity without changing the front-end light collection and spectral splitting. In one exemplary form, the back-end imaging optics (e.g., one or more optical elements 106) can be designed such that, for a detector area of a fixed size, the energy within one spectral band 165 is imaged on the detector array 108 at a different, larger height by reducing the height or number of the other spectral bands 165. Alternatively, in another exemplary form, two or more spectral bands 165 can be made the same (e.g., spectral band 165a and spectral band 165d in FIG. 3), and the power of those spectral bands 165 can be evenly divided.

[0042] In the example of detector array 108 shown in FIG. 3, spectral band 165c has a height that is twice that of spectral band 165a in detector array 108 (e.g., 200 pixels for 100 pixels) (e.g., the height of detector area 110 where spectral band 165c is imaged is twice the height of detector area 110 where spectral band 165a is imaged). Here, when the energy (e.g., power or throughput) of the entire spectral band 165 is equal, spectral band 165c has a pulse energy per pixel that is reduced to one-half compared to spectral band 165a (and spectral band 165d). The figure in FIG. 4 shows the effect of the reduction in energy density (e.g., energy per pixel) on detector array 108 for two channel sizes, a spectral channel with a specific width and height of 100 pixels and a spectral channel with a specific width and height of 200 pixels. As shown in FIG. 4, the higher channel (i.e., the spectral channel with a height of 200 pixels) has a larger dynamic range for count detection. This leads to an improvement in sensitivity. In the figure shown in FIG. 4, as the pulse energy further increases, the detection count per pulse ultimately saturates detector array 108, which means that detector array 108 cannot perform further count detection even as the pulse energy increases. In some forms, by increasing the height (e.g., and number of pixels) assigned to a given spectral band 165, the sensitivity and saturation limit can be increased.

[0043] In one form, a first spectral band 165x with a relatively small bandwidth can be imaged onto a first detector area 110x of the detector array 108, and a second spectral band 165y with a relatively large bandwidth can be imaged onto a second detector area 110y of the detector array 108. Here, in the dispersion direction, the total width and pixel size (i.e., resolution) of the first detector area 110x match the total width and pixel size (i.e., resolution) of the second detector area 110y in the dispersion direction. In this way, when the optical resolution of the first spectral band 165x matches the optical resolution of the second spectral band 165y, the first spectral band 165x can have a higher spectral resolution than the second spectral band 165y (for example, because each detector pixel receives fewer wave numbers for the first spectral band 165x with a relatively small bandwidth).

[0044] As described above, FIGS. 3 and 4 are provided as examples. Other examples may differ from those described with respect to FIGS. 3 and 4.

[0045] FIGS. 5-7 are diagrams showing exemplary forms of the separation element 102 described herein. In some forms, as described above, the separation element 102 can include one or more elements that spatially or angularly separate the optical signal 160 into a plurality of spectral bands 165 such that each spectral band 165 is spatially or angularly separated from the other spectral bands 165. In some forms, the separation element 102 can include a plurality of thin film interference filters, each associated with a different spectral band 165 of the plurality of spectral bands 165. FIG. 5 is a diagram showing an exemplary form of the separation element 102 including a plurality (e.g., four) of thin film interference filters 502. Additionally or alternatively, these can include diffraction gratings. FIGS. 6 and 7 are diagrams showing exemplary forms of the separation element 102 including diffraction gratings 602. Additionally or alternatively, the separation element 102 can include one or more other types of optical elements.

[0046] In one form, the light of the optical signal 160 having a wavelength near the boundary between two spectral bands 165 can be split by the splitting element 102 such that each portion of the light enters a plurality of spectral bands 165. Thus, in some forms, the spectral components at or near the boundary between a first spectral band 165 of the plurality of spectral bands 165 and a second spectral band 165 of the plurality of spectral bands 165 can be split such that a first portion of the spectral component is within the first spectral band 165 and a second portion of the spectral component is within the second spectral band 165. Here, the sum of the power of the first portion and the power of the second portion is the total power of the spectral component.

[0047] In the example shown in FIG. 5, the optical signal 160 includes the full spectrum generated from the sample 155 (e.g., as in FIG. 1). Here, each thin-film interference filter 502 reflects only a portion of the full spectrum (e.g., spectral band 165) and transmits the remainder. In some forms, as shown in FIG. 5, a sequence of a plurality (e.g., four) of interference filters 502, followed by a mirror 504, splits the full spectrum into a plurality (e.g., five) of spatially separated spectral bands 165. They then enter a focusing lens 506. Thereby, the spatial separation (e.g., offset) is converted into an angular separation (e.g., angle) of different spectral bands 165. Thereafter, the spectral bands 165 can be imaged onto a plane for further optical processing. With respect to the optical device 100 described in FIG. 1, the spatially / angulary separated spectral bands 165 are then directed towards the dispersive element 104.

[0048] In the example shown in FIGS. 6 and 7, an optical signal 160 including the full spectrum generated from sample 155 (e.g., as shown in FIG. 2) is collimated by lens 604 and directed towards a diffraction grating 602 that separates the incident light into different spectral components (e.g., wavelengths). The diffracted light emerging from diffraction grating 602 is focused by lens 606 and imaged to produce spectrally separated bands 165 that are spatially and angularly separated. The imaging system shown in FIG. 7 includes a wedge 702 and prisms 704a and 704b that serve to change the optical path lengths and propagation angles of the beams in spectral band 165 such that the resulting spectral beams appear to arrive at a single focal plane from different angles (e.g., similar to that achieved in the example shown in FIG. 5). With respect to optical device 100 described in FIG. 1, the spectrally separated bands 165 that are spatially / angulary separated are then directed towards dispersive element 104.

[0049] As described above, FIGS. 5 - 7 are provided by way of example. Other examples may differ from those described with respect to FIGS. 5 - 7. The number and arrangement of the elements shown in FIGS. 5 - 7 are provided as an example. In practice, there may be additional elements, fewer elements, different elements, or elements in a different arrangement than those shown in FIGS. 5 - 7. Further, two or more of the elements shown in FIGS. 5 - 7 may be implemented within a single element, or a single element shown in FIGS. 5 - 7 may be implemented as a plurality of distributed elements. Additionally or alternatively, a set of elements (e.g., one or more elements) shown in FIGS. 5 - 7 may perform one or more functions as described to be performed by a different set of elements shown in FIGS. 5 - 7.

[0050] FIG. 8 is a flowchart of an exemplary process 800 related to the flex - spectrum optical detector described herein. In some forms, one or more of the process blocks in FIG. 8 are performed by one or more elements of an optical device (e.g., optical device 100).

[0051] As shown in FIG. 8, process 800 may include separating an optical signal into a plurality of spectral bands having different spectral ranges and spatially or angularly separated along a band separation direction (block 810). For example, the separation element 102 of the optical device 100 may separate the optical signal 160 into a plurality of spectral bands 165 having different spectral ranges and spatially or angularly separated along the band separation direction, as described above.

[0052] As further shown in FIG. 8, process 800 may include dispersing spectral components of one of the plurality of spectral bands along a dispersion direction to form a dispersed spectral band (block 820). For example, the dispersion element 104 of the optical device 100 may disperse spectral components of one of the plurality of spectral bands 165 along the dispersion direction to form a dispersed spectral band 165, as described above.

[0053] As further shown in FIG. 8, process 800 may include operating the dispersed spectral band in relation to imaging the spectral band on a detector area of a detector array of the optical device (block 830). For example, the optical element 106 of the optical device 100 may operate the dispersed spectral band 165 in relation to imaging the spectral band 165 on the detector area 110 of the detector array 108 of the optical device 100, as described above.

[0054] Process 800 may include additional forms, such as a single form or any combination of forms, in relation to one or more other processes described below and / or elsewhere in this specification. In a first form, the characteristics (e.g., optical resolution) of a first dispersed spectral band 165 among the plurality of dispersed spectral bands 165 are different from the characteristics of a second dispersed spectral band 165 among the plurality of dispersed spectral bands 165.

[0055] In some forms, at least one of the position, size, or orientation (direction) of the operated distributed spectral band 165 formed by the operation of the distributed spectral band 165 is different from the position, size, or orientation of the second operated distributed spectral band 165 formed by the operation of the second distributed spectral band 165.

[0056] In some forms, each separated spectral band 165 can be dispersed by the dispersive element 104, but in other forms, one or more spectral bands 165 separated from the optical signal 160 can be oriented away from the dispersive element 104 and / or the detector array 118 (e.g., as shown with respect to spectral band 165b in FIG. 1).

[0057] FIG. 8 shows an exemplary block of process 800, and in some forms, process 800 includes additional blocks, fewer blocks, different blocks, or blocks in a different arrangement than those shown in FIG. 8. Additionally or alternatively, two or more blocks of process 800 may be executed in parallel.

[0058] The foregoing disclosure provides examples and explanations, but is not intended to be exhaustive or to limit the forms to the exact form disclosed. Modifications and changes may be made in light of the above disclosure, or may be realized from the practice of the forms. Further, any forms described herein may be combined unless the foregoing disclosure clearly indicates a reason why one or more forms cannot be combined.

[0059] Particular combinations of features are recited in the claims and / or disclosed in the specification, but these combinations are not intended to limit the disclosure in various forms. In fact, many of these features can be combined in ways that are not specifically recited in the claims and / or disclosed in the specification. Each of the dependent claims listed below may depend directly on only one claim, but the disclosure in various forms includes each dependent claim combined with each other claim within the set of claims. As used herein, the expression "at least one of" a list of items refers to any combination of these items, including a single member. By way of example, "at least one of a, b, or c" is intended to cover a, b, c, a and b, a and c, b and c, and a and b and c, as well as any combination of multiple of the same items.

[0060] When one component or more than one component (e.g., one optical element or more than one optical element) is described or claimed as performing or being configured to perform a plurality of operations (within one claim or across a plurality of claims), this expression is intended to broadly cover various configurations and environments. For example, unless otherwise explicitly stated (e.g., by the use of "first component" and "second component" in the claim or other expressions differentiating components), this expression is intended to cover a single component that performs or is configured to perform all operations, a group of components configured to perform all operations together, a first component configured to perform a first operation, and a second component configured to perform a second operation, or any combination of components configured to perform operations. For example, if the claim is in the form of "one or more components configured to perform X, perform Y, and perform Z", the claim should be interpreted as meaning "one or more components configured to perform X, one or more (which may be different) components configured to perform Y, and one or more (which may also be different) components configured to perform Z".

[0061] None of the elements, acts, or instructions used in this specification should be construed as essential or critical, unless so expressly indicated. Further, as used in this specification, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." Further, as used in this specification, the article "the" is intended to include one or more items referred to in combination with the article "the" and may be used interchangeably with "the one or more." Further, as used in this specification, the term "set" is intended to include one or more items (e.g., related items, unrelated items, or combinations of related and unrelated items) and may be used interchangeably with "one or more." When only one item is intended, the expression "only one" or a similar expression is used. Further, as used in this specification, terms such as "has," "have," or "having" are intended as open-ended terms. Further, the expression "based on" is intended to mean "at least in part based on," unless so expressly indicated. Further, as used in this specification, the term "or" is intended to be inclusive when used in a series, and may be used interchangeably with "and / or," unless so expressly indicated (e.g., when used in combination with "either" or "only one of"). Further, terms related to space such as "below," "lower," "above," and "upper" may be used in this specification for convenience in describing the relationship of one element or feature to another illustrated element or feature. Terms related to space are intended to include different orientations of the devices, devices, and / or elements being used or operating, in addition to the illustrated orientation. This device may be oriented in a different form (rotated 90 degrees or in a different orientation). Accordingly, the descriptions related to space used in this specification may be interpreted similarly.

Explanation of Reference Numerals

[0062] 100 Optical device 102 Separation element 104 Dispersion element 106 Optical element 108 Detector array 110 Detector area 145 Light source 150 Light source light 155 Sample 160 Optical signal 165 Spectral band 502 Thin film interference filter 504 Mirror 506 Focusing lens 602 Diffraction grating 604, 606 Lenses 702 Wedge 704a, 704b Prisms

Claims

1. A plurality of spectral bands spatially or angularly separated along a band separation direction, wherein the spectral ranges are different between each of the spectral bands of the plurality of spectral bands, and a separation element that separates an optical signal into the plurality of spectral bands; A dispersion element having a plurality of dispersion regions, wherein one of the plurality of dispersion regions forms a dispersed spectral band by dispersing spectral components of one of the plurality of spectral bands along a dispersion direction; A plurality of optical elements, wherein one of the plurality of optical elements operates on the dispersed spectral band in relation to imaging the spectral band on a detector area of a detector array; The detector array including the detector area; An optical device comprising the above.

2. The optical device according to claim 1, wherein the band separation direction is perpendicular to the dispersion direction.

3. The optical device according to claim 1, wherein the plurality of spectral bands do not substantially overlap.

4. The optical device according to claim 1, wherein the spectral resolution of a first spectral band among the plurality of spectral bands is different from the spectral resolution of a second spectral band among the plurality of spectral bands.

5. The optical device according to claim 1, wherein the bandwidth of a first spectral band among the plurality of spectral bands is different from the bandwidth of a second spectral band among the plurality of spectral bands.

6. The optical device according to claim 1, wherein the spectrum formed by the sum of a set of spectral bands imaged on the detector array among the plurality of spectral bands is discontinuous.

7. The optical device according to claim 1, wherein at least one of the plurality of spectral bands is not imaged on any detector area of the detector array.

8. The optical device according to claim 1, wherein the optical power of one of the plurality of spectral bands in the detector array exceeds 90% of the optical power of the spectral band before the separation element.

9. At the boundary between the first spectral band among the plurality of spectral bands and the second spectral band among the plurality of spectral bands, or in the vicinity of the boundary, the spectral component is divided such that a first portion of the spectral component is within the first spectral band and a second portion of the spectral component is within the second spectral band, and the sum of the power of the first portion and the power of the second portion is the total power of the spectral component. The optical device according to claim 1.

10. The separation element includes a plurality of thin-film interference filters, and each thin-film interference filter is associated with a different spectral band among the plurality of spectral bands. The optical device according to claim 1.

11. The separation element includes a diffraction grating. The optical device according to claim 1.

12. The plurality of dispersion regions are stacked along the band separation direction. The optical device according to claim 1.

13. A given dispersion region among the plurality of dispersion regions disperses one spectral band among the plurality of incident spectral bands independently of the dispersion by other dispersion regions among the plurality of dispersion regions. The optical device according to claim 1.

14. The optical element operates on the dispersed spectral band such that the size of the dispersed spectral band along the dispersion direction matches the size of the detector area along the dispersion direction. The optical device according to claim 1.

15. The optical element operates on the dispersed spectral band such that the size of the dispersed spectral band along the band separation direction matches the size of the detector area along the band separation direction. The optical device according to claim 1.

16. The plurality of optical elements operate on the dispersed spectral band such that images of the spectral bands are stacked along the band separation direction in the plane of the detector array. The optical device according to claim 1.

17. The plurality of optical elements realize a spatial rearrangement of the plurality of spectral bands on the plane of the detector array. The optical device according to claim 1.

18. The detector array includes a plurality of detector areas stacked along the band separation direction. The optical device according to claim 1.

19. The optical device according to claim 1, wherein the detector array is a two-dimensional (2D) array.

20. The optical device according to claim 1, wherein the detector array includes one or more one-dimensional (1D) detector arrays.

21. The optical device according to claim 1, wherein the detector array is a single photon avalanche diode (SPAD) array.

22. The optical device according to claim 1, wherein the detector array includes an array of time-resolved photon counting detectors.

23. The optical device according to claim 1, wherein the detector area includes a plurality of detector areas, and a size of a first detector area among the plurality of detector areas is different from a size of a second detector area among the plurality of detector areas.

24. The optical device according to claim 1, wherein the detector area includes a plurality of detector areas, a first spectral band among the plurality of spectral bands is imaged on a first detector area among the plurality of detector areas, a second spectral band among the plurality of spectral bands is imaged on a second detector area among the plurality of detector areas, an optical resolution of the first spectral band coincides with an optical resolution of the second spectral band, a bandwidth of the first spectral band is smaller than a bandwidth of the second spectral band, a total width and number of pixels of the first detector area in the dispersion direction coincide with a total width and number of pixels of the second detector area in the dispersion direction, whereby the first spectral band has a higher spectral resolution than the second spectral band.

25. The optical device according to claim 1, wherein the detector area includes a plurality of detector areas, a size of a first detector area among the plurality of detector areas in the dispersion direction coincides with a size of a second detector area among the plurality of detector areas in the dispersion direction, and a size of the first detector area in the band separation direction is different from a size of the second detector area in the band separation direction.

26. A separating element that separates an optical signal into a plurality of spectral bands having different spectral ranges and spatially or angularly separated along a band separation direction, A plurality of optical elements, wherein one of the plurality of optical elements operates on one of the plurality of spectral bands in relation to imaging the spectral band on a detector area. A detector array including the detector area. An optical device comprising the same.

27. The optical device according to claim 26, further comprising a dispersive element including a plurality of dispersive areas, wherein one of the plurality of dispersive areas disperses spectral components of the spectral band along a dispersion direction.

28. Separating an optical signal into a plurality of spectral bands having different spectral ranges and spatially or angularly separated along a band separation direction by a separating element of the optical device. Forming a dispersed spectral band by dispersing spectral components of one of the plurality of spectral bands along a dispersion direction by a dispersive element of the optical device. Operating the dispersed spectral band in relation to imaging the spectral band on a detector area of a detector array of the optical device by an optical element of the optical device. A method comprising the same.

29. The method according to claim 28, wherein characteristics of a first dispersed spectral band among the plurality of dispersed spectral bands are different from characteristics of a second dispersed spectral band among the plurality of dispersed spectral bands.

30. The method according to claim 28, wherein at least one of a position, a size, or an orientation of an operated dispersed spectral band formed by the operation of the dispersed spectral band is different from a position, a size, or an orientation of a second operated dispersed spectral band formed by the operation of a second dispersed spectral band.

Images