SYSTEMS AND METHODS TO REDISTRIBUTE FIELD OF VIEW IN SPECTROSCOPY

An apparatus includes a substrate and an optically powered surface. The substrate is transmissive of electromagnetic energy, and includes a plurality of reflective portions oriented and positioned to control a propagation direction of electromagnetic energy along an optical path of the substrate. The substrate further includes an input surface aligned with the optical path so as to allow electromagnetic energy to enter the substrate through the input surface. The optically powered surface is positioned relative to the substrate so as to redirect a field of view of the substrate. The field of view of the substrate is bounded by a first angular width, a field of view of the optically powered surface is bounded by a second angular width, and the second angular width is different than the first angular width.

BACKGROUND

Technical Field

The present disclosure relates generally to systems and methods to redistribute a field of view for use in optical applications. More specifically, the present disclosure describes the use of curved mirrors to adjust the field of view for optical analytical instruments, such as spectrometers.

Description of the Related Art

Spectrometers are analytical instruments that are able to identify the wavelengths that comprise incident electromagnetic energy (e.g., light), and provide spectral content information or data that characterizes the constituent components of the incident electromagnetic energy. Spectrometers are useful in a large variety of settings and applications. For example, spectroscopy can be used to analyze the color of light, the content of a number of chemical processes and reagents, the authenticity of documents, and many other applications in which the wavelength of light is modified by a target.

U.S. Pat. No. 8,854,624, generally describes a photonic crystal based spectrometer. U.S. Pat. No. 8,854,624, is an example of use of photonic crystals as scattering structures, and describes scattering from guided modes to free-space propagating modes. Known photonic crystal based spectrometers include a photonic crystal coupled to an outer surface of an optical waveguide to extract a portion of optical energy propagating through the waveguide via the photonic crystal.

Known spectrometers are designed with a field of view within which useful light is transmitted to the optically active elements of the spectrometer. Light outside of this field of view is considered “stray light” and may be rejected by the spectrometer as the stray light can lead to false signals and an incorrect final spectrum. Typically, the field of view for a given spectrometer is relatively small, for example compared to that of a human eye. Known spectrometers manufactured by Chromation have a field of view between about 2 degrees to about 3 degrees. Other known spectrometers, for example an industry standard Czerny-Turner spectrometer design can have a field of view of about 25.4 degrees. A human eye typically has a horizontal arc field of view of about 210 degrees and a vertical arc field of view of about 150 degrees. Numerous applications may benefit from a wider field of view for a given spectrometer, as a wider field of view will provide more light to the spectrometer thereby increasing sample size and reducing bias from a narrow area outlier.

BRIEF SUMMARY

Advantageously, an article can employ input optics and/or output optics to facilitate entry of electromagnetic energy (e.g., light including visible, infrared and/or ultraviolet ranges) onto an electromagnetic energy transmissive path. At least a portion of the path may be formed within an electromagnetic energy transmissive structure, such as a substrate (e.g., optically transmissive substrate, optical waveguide, planar waveguide), to facilitate extraction or exiting of electromagnetic energy out of the electromagnetic energy transmissive structure. At least a portion of the path may pass through a cavity, for example a cavity filled with a gaseous substance, such as air, or the cavity enclosing a vacuum, to facilitate extraction or exiting of electromagnetic energy out of the cavity.

An article can employ various types of nanostructures or regions of nanostructures as input optics and/or output optics, to respectively facilitate entry of electromagnetic energy respectively into and out of an electromagnetic energy transmissive structure such as a substrate. Additionally or alternatively, an article can employ a variety of other types of input optics, for example, apertures, mirrors or reflectors, prisms, focusing optics or lenses, and/or reflective or refractive surfaces to couple electromagnetic energy into the substrate.

According to one implementation an apparatus includes a substrate and an optically powered surface with a non-planar shape. As used herein, an optically powered surface refers to a surface which acts upon electromagnetic energy that contacts the optically powered surface. An optically powered surface reflects or refracts electromagnetic energy and examples of optically powered surfaces include lenses, prisms, mirrors, nanostructures, and filters. According to some implementations, the optically powered surface acts upon the electromagnetic energy without modifying the spectral content of the electromagnetic energy.

The substrate is transmissive of electromagnetic energy and supports a plurality of reflective portions oriented and positioned to control a propagation direction of the electromagnetic energy along an optical path. The substrate further includes an input surface aligned with the optical path so as to allow the electromagnetic energy to enter the substrate through the input surface. The substrate further including an input field of view within which electromagnetic energy that passes through the input surface propagates within the substrate by reflecting off of the plurality of reflective surfaces supported by the substrate. The optically powered surface is positioned relative to the substrate so as to the redirect electromagnetic energy within a field of view of the optically powered surface. The field of view of the substrate bounded by a first angular width, the field of view of the optically powered surface is bounded by a second angular width, and the second angular width is different than the first angular width.

According to one implementation a method of analyzing electromagnetic energy includes redirecting electromagnetic energy within a first field of view of an optically powered surface with the optically powered surface into a second field of view of a substrate such that the redirected electromagnetic energy passes through an input surface of the substrate. The method further includes, after redirecting the electromagnetic energy, reflecting the electromagnetic energy off of a plurality of reflective surfaces supported by the substrate. The method further includes, after reflecting the electromagnetic energy, separating various components of the electromagnetic energy, wherein the first field of view is bounded by a first angular width, the second field of view is bounded by a second angular width, the first angular width is different than the second angular width, and at least a portion of the first field of view is positioned outside the second field of view.

According to one implementation a method of fabricating an apparatus includes positioning a substrate, which is transmissive of electromagnetic energy, such that an optical path is established along which electromagnetic energy that enters the substrate through an input optic of the substrate propagates within the substrate. The method further includes positioning an optically powered surface relative to the substrate, such that the optically powered surface redirects electromagnetic energy within a first field of view of the optically powered surface into a second field of view of the substrate, the second field of view extending out from the input surface and including all angles along which electromagnetic energy that enters the substrate through the input surface will propagate within the substrate. The first field of view has a first angular width, the second field of view has a second angular width, and the second angular width is different than the first angular width.

DETAILED DESCRIPTION

The term “aligned” as used herein in reference to two elements along a direction means a straight line that passes through one of the elements and that is parallel to the direction will also pass through the other of the two elements. The term “between” as used herein in reference to a first element being between a second element and a third element with respect to a direction or path means that the first element is closer to the second element as measured along the direction or path than the third element is to the second element as measured along the direction or path. The term “between” includes, but does not require that the first, second, and third elements be aligned along the direction or path.

Referring toFIG.1an apparatus100, according to one illustrated implementation, includes a substrate102, which transmits electromagnetic energy of at least a set of wavelengths or frequencies that are of interest (i.e., ranges of wavelengths or frequencies that are to be detected or sensed or measured, e.g., electromagnetic energy in the optical range of wavelengths including electromagnetic energy in the visible range, the infrared range, and the ultraviolet range of the electromagnetic spectrum). According to one embodiment, the apparatus100includes a cavity103in place of the substrate102. The cavity103may be filled with a gaseous substance, such as air, or the cavity103may enclose a vacuum, to facilitate extraction or exiting of electromagnetic energy out of the cavity103. Although shown only inFIG.1, any of the embodiments of the apparatus100described herein may include the cavity103in place of the substrate102.

The apparatus100also includes an input surface104positioned and oriented to allow electromagnetic energy that intersects the input to pass into the substrate102. The input surface104may include an optically powered surface (e.g., a lens, a mirror, etc.), or alternatively may provide passage into the substrate102without changing the characteristics (e.g., the direction of the electromagnetic energy) as it passes through the input surface104.

The apparatus100may further include an output optic110laterally spaced from the input surface104along a length L of the substrate102. In at least some implementations, the output optic110is in the form of regions of nanostructures, positioned and oriented proximate to a top major face108of the substrate102, a bottom major face112of the substrate102(as shown), or an edge109of the substrate, to cause at least a portion of the electromagnetic energy (represented by a arrows114, only one labeled) to pass out of the substrate102. The output optic110may be formed in a respective layer or structure that is distinct from the substrate102. In some implementations, the output optic110may be formed directly on and/or in the substrate102. While illustrated as employing one output optic110, some implementations may employ more than one output optic. Where there are two or more output optics, the output optics may be generally spaced along at least a length L of the substrate102.

According to one implementation, the top major face108and the bottom major face112may be distinguishable from the edge109of the substrate102in that major faces108and112extend along two major axes of the substrate102, that is the length L and a width W (not shown, into the page of the illustrated embodiment), while the edge109extends along a minor axis, that is a thickness T. It should be noted that in some implementations, the length L and the width W of the substrate102may be unequal to each other, such that the substrate102has a rectangular profile. In other implementations, the length L and the width W of the substrate102may be equal to one another, such that the substrate102has a square profile. In some instances, the substrate may transmit electromagnetic energy without total internal reflection.

The apparatus100may optionally include one or more detectors116(only one shown), positioned to detect electromagnetic energy that passes out of the substrate102. As illustrated inFIG.1, the detector116may be separated from the output optic110by a coupling layer or spacer118of a suitable thickness (e.g., 3 mm, less than 3 mm). In some implementations, one or more optical fibers (e.g., a faceplate) may extend between the output optics110and the detector116. The coupling layer118or optical fibers are at least transmissive of electromagnetic energy of at least a set of wavelengths or frequencies that are of interest, and in most implementations, propagate light entering at such appropriate angles (e.g., via total internal reflection) from the output optics110to the detector116.

The detector(s)116may take any of a variety of forms. For example, the detector(s)116may advantageously take the form of one or more optical detectors, sensors or transducers that are responsive to optical wavelengths or frequencies of electromagnetic energy, e.g., light in the visible, infrared and/or ultraviolet portions of the electromagnetic spectrum. Also for example, the detector(s)116may advantageously take the form of one or more optical linear detector arrays which are responsive to light at various positions along a length of the detector116. The detector(s)116may, for example, take the form of one or more charge-coupled devices (CCDs), and/or one or more complementary-metal-oxide-semiconductor (CMOS) image detectors and/or other optical detector(s), sensor(s) or transducer(s) that produce signals (e.g., electrical signals) in response to incident light.

According to one implementation, the detector116may be 2D, such that the detector includes multiple pixels extending along both the length L and the width W. A 2D detector116may be advantageous in various applications, for example in making a push-broom hyperspectral imager.

The substrate102may, for example, take the form of a plane, substrate, or layer of electromagnetic energy transmissive material (e.g., optically transmissive material). The plane, substrate, or layer of transmissive material can be generally transmissive of electromagnetic energy of at least certain wavelengths or frequencies of interest (i.e., wavelengths or frequencies to be detected or sensed, e.g., light including visible, infrared and/or ultraviolet ranges), without any propensity to guide the electromagnetic energy (i.e., transmissive without total internal reflection). As a non-limiting example, the substrate102may be formed from fused silica.

Electromagnetic energy may be indiscriminately transmitted throughout the substrate102. In some example implementations, nanostructures formed in or on the substrate102or otherwise optically coupled to the substrate can cause specific wavelength components of the electromagnetic energy to exit (e.g., be extracted from) the substrate. This approach can be employed to spatially resolve the components of the electromagnetic energy, which can be detected or sensed by a detector or sensor, and converted into information (e.g., raw information in analog or digital form) that is representative of wavelength distribution in the incident light. In other implementations, one or more other types of output optics may be included, such as apertures, filters, diffusers, lenses, etc.

In some implementations, the apparatus100may include one or more optical elements111(e.g., reflectors, spectrally selective elements, absorbers, dispersive and refractive elements, and diffusers). In some implementations, reflectors may be supported on or proximate to major faces of the substrate102to increase a length of a path for non-guided electromagnetic energy within the substrate102. Additionally, patterned reflectors may be supported on or proximate to major faces of the substrate102to shape propagating electromagnetic energy distribution.

Each of the reflectors used for shaping the propagating electromagnetic energy distribution may be defined on the same major face of the substrate102or on different major faces. In some implementations, patterned reflectors on or proximate to major faces of the substrate102may be used to translate input electromagnetic energy toward one or more of the output optics110along the length L or width W of the substrate102. Moreover, reflectors may be used to direct electromagnetic energy along an optical path117and/or to direct unwanted electromagnetic energy away from the optical path117.

Spectrally selective elements may be formed within or supported on major faces of the substrate102to cause separation in the wavelength distribution of electromagnetic energy. Examples of spectrally selective elements may include diffractive, refractive, prismatic, scattering, and filter elements. In some implementations, reflection or transmission gratings may be formed on a major face of the substrate102to cause separation in the wavelength distribution of electromagnetic energy incident upon the spectrally selective elements.

Further, interference filters may be created on major faces of the substrate102to define a range of wavelengths which remain in the substrate102or exit the substrate102. As noted above, photonic crystals may be used to scatter electromagnetic energy within the substrate102and out of the substrate102.

In some implementations, patterned absorbers may be supported by one or more major faces of the substrate102to alter the propagating electromagnetic energy distribution. Such absorbers are discussed further below.

In some implementations of the present disclosure, patterned dispersive elements (e.g., Fresnel lenses, zone plates) are created on one or more major faces of the substrate102to define or reshape the electromagnetic energy distribution along the optical path117. A curved mirror may also be created on a major face of the substrate to couple to one or more waveguide modes of the substrate or to reshape non-guided electromagnetic energy along the optical path.

In some implementations, a diffuser may be created on one or more of the major faces of the substrate102to alter the incident or exiting angular distribution of electromagnetic energy. Patterned diffusers may also be formed on one or more major faces of the substrate102to alter the angular distribution of a specific portion of electromagnetic energy along the optical path117.

For at least some of the implementations discussed herein, optical structures supported on or proximate to major faces may be created by nanofabrication, bonding, or alignment of external components to the substrate, for example. Features on opposing major faces of the substrate102may be aligned to achieve the desired alteration of electromagnetic energy distribution along the folded optical path117.

The optical elements may include a number of reflector portions or regions122a-122e(“reflectors”) and may optionally include a number of absorber portions or regions120a-120b(“absorbers”). In the illustrated example ofFIG.1, the absorber120ais proximate (e.g., adjacent or above) the top major face108of the substrate102and the absorber120bis proximate (e.g., adjacent or below) the bottom major face112of the substrate. Also as shown, the reflectors122a-122cmay be proximate the top major face108of the substrate102and the reflectors122d-122emay be proximate the bottom major face112of the substrate.

In some implementations, the reflectors122may be formed from reflective biaxially-oriented polyethylene terephthalate material (e.g., reflective Mylar®), deposited metal (e.g., aluminum), etc. In some implementations, the absorbers120may be formed from paint (e.g., black paint), paper (e.g., black paper), an absorptive coating or film, etc. In some implementations, the absorbers120may be filters that generally pass some wavelengths and/or frequencies of the electromagnetic energy and reflect others. In some instances some nominal amounts of the electromagnetic energy (e.g., wavelengths intended to be passed, wavelengths to be reflected, or wavelengths to be passed and reflected) may be absorbed (e.g., via heating the filter). In some implementations the apparatus100may include a wide band absorber that absorbs wavelengths and/or frequencies over all optical wavelengths, or alternatively, all wavelengths of interest (e.g., a subset of optical wavelengths).

The input surface104, absorbers120, reflectors122and/or output optic110may each be supported by, for example in direct contact with or proximate to one of the top major face108or the bottom major face112of the substrate102. The absorbers120may form a coating or cladding that at least partially surrounds the substrate102. The coating or cladding may provide an interface with one or more surfaces of the substrate102with a high ratio of refractive index (e.g., so as to facilitate total internal reflection for electromagnetic energy that enters the substrate102at an angle larger than a critical angle of the substrate).

According to one implementation the top major face108is formed of a single, continuous, planar surface, and the bottom major face112is similarly formed of a single, continuous, planar surface. Alternatively or additionally, one or more of such components may be distinct unitary separable elements that may or may not span the entire major faces. As another alternative, one or more of such components may be integrated into or directly on the substrate102. As shown, the input surface104may be formed in one of the edges109of the substrate102.

In the embodiment of the apparatus100ofFIG.1, the reflector regions122and absorber regions120are defined on both the top and bottom major faces108,112to structure the range of angles of the electromagnetic energy160. For example, the spatial extent of the reflector122dspatially limits the electromagnetic energy reflected by the reflector122d. The absorbers120badjacent the reflector122dfunctions to manage stray light. In some implementations, absorbers may not be present adjacent the top or bottom major faces108,112of the substrate102. In such implementations, light which passes adjacent a reflector may simply be transmitted out of the substrate102, where it may be absorbed by another component (e.g., an absorptive feature or system within a housing which contains the substrate102). Similarly, the spatial extent of the reflector122aspatially limits the electromagnetic energy reflected by the reflector122a.

By selecting the patterns of reflectors (and optionally absorbers), the electromagnetic energy may be shaped and translated along a portion of an optical path117from the input surface104to the output optic110(or at least adjacent to the output optic110). For example, such patterns may be selected to limit the numerical aperture of the electromagnetic energy incident on or adjacent to the output optic110and/or to limit the range of propagation angles of the electromagnetic energy within the substrate102. Photons that are incident on the output optic110may pass out of the substrate102, whether those photons are from a light beam or ray that has a principal axis that directly intersects the output optic110, or has a principal axis that does not directly intersect the output optic110, for instance a light beam or ray that has a principal axis that intersects a location that is adjacent the output optic. The reflectors122and absorbers120may be stacked layers external to the substrate102(e.g., with air gaps in the negative spaces of the absorbers). In some implementations these structures may be fabricated directly on the major faces108and112of the substrate102, for example using nanofabrication techniques.

Based on one or more of the physical components of the substrate102as described above, (e.g., the optical elements111) the substrate102may include an input field of view130. In some implementations, the input field of view130may be defined using multiple features positioned on one or more major faces of the substrate102. In some instances, the defining optical features used to define viewing angle may be separated by non-defining optical features along the folded optical path. Electromagnetic energy that enters the substrate102through the input surface104, within the input field of view130, may be reflected by one or more of the reflectors122to reach the output optic110. The input field of view130is bounded by an angular width α (alpha). The substrate102may further include an input angle β (beta), measured from a plane P1, within which a number of the reflectors122(e.g., the reflectors122d-e) lie, to a center line132of the input field of view130. The input angle β (beta) may be referred to as the angle-of-attack for the substrate102.

Due to constraints within the design of the substrate102, the input field of view130is typically small, e.g., between about 2-3°, and up to about 10°. A larger field of view may be advantageous in a number of applications, for example when data for a larger area is desired, or where collection of electromagnetic energy from many different directions is desired. Increasing the input field of view130without compromising performance of the apparatus100is challenging. For example, increasing the size of the input surface104may require increasing the size of the apparatus100which may compromise a desired, compact, surface-mounted form factor for the apparatus100. Additionally, changes to the size of the input surface104, or the portion of the optical path117within the substrate102may negatively impact the effective resolution of the apparatus100.

As shown inFIG.1, the apparatus100may include an optically powered surface with a non-planar shape150(hereinafter “the optically powered surface150”) positioned so as to redirect the input field of view130, such that electromagnetic energy within a redirected field of view152, at least a portion of which is outside the input field of view130, is redirected into the input field of view130, through the input surface104, and onto the optical path117. The redirected field of view152of the optically powered surface150may be bounded, as shown, by an angular width θ (theta). The optically powered surface150may further include an input angle λ (lambda), measured from the plane P1, to a center line154of the redirected field of view152of the optically powered surface150. The input angle λ (lambda) may be referred to as the angle-of-attack for the optically powered surface150.

The characteristics (e.g., shape) and position (e.g., outside the substrate102and aligned with the optical path117as it exits the input surface104) of the optically powered surface150may be tailored to enable electromagnetic energy from a different field of view, a different direction, or both to enter the input surface104along the optical path117. As will be explained in detail below, the redirected field of view152of the optically powered surface150may have a greater angular width than the input field of view130of the substrate102.

According to one implementation, the angular width θ (theta) may be at least double the angular width α (alpha). According to one implementation, the angular width θ (theta) may be at least ten times the angular width α (alpha). According to one implementation, the angular width θ (theta) may be at least twenty times the angular width α (alpha). According to one implementation, the angular width θ (theta) may be at least fifty times the angular width α (alpha). According to one implementation, the angular width θ (theta) may be 45° or greater. According to one implementation, the angular width θ (theta) may be 60° or greater. According to one implementation, the angular width θ (theta) may be 90° or greater. According to one implementation, the angular width θ (theta) may be 120° or greater. According to one implementation, the angular width θ (theta) may be between 45° and 120°. As will be explained in detail below, the redirected field of view152of the optically powered surface150may have a smaller angular width than the input field of view130of the substrate102such that the angular width θ (theta) is less than the angular width α (alpha).

The characteristics of the optically powered surface150may be tailored such that the electromagnetic energy that enters the substrate102through the input surface104(referred to herein as the input bundle) is collimated. Alternatively, the characteristics of the optically powered surface150may be tailored such that the electromagnetic energy that passes through the input surface104along the optical path117is not collimated.

The characteristics of the optically powered surface150may be tailored such that the electromagnetic energy within the redirected field of view152that is redirected to pass through the input surface104along the optical path117is uniformly distributed. Alternatively, characteristics of the optically powered surface150may be tailored such that the electromagnetic energy within the redirected field of view152that is redirected to pass through the input surface104along the optical path117is non-uniformly distributed.

According to one implementation the input angle λ (lambda) may be different than the input angle β (beta). As shown, the input angle β (beta) may be 45° and the input angle λ (lambda) may be 90°. According to one implementation, the input angle β (beta) may be 90°. According to one implementation, the input angle λ (lambda) may be 0° (such that the center line154extends away from the optically powered surface150to the left from the view shown inFIG.1). According to one implementation, the input angle λ (lambda) may be 180° (such that the center line154extends away from the optically powered surface150to the right from the view shown inFIG.1).

In certain applications there may be a desired area within which the electromagnetic energy is to be collected. The optically powered surface150may enable the use of a substrate102with a given input angle to collect electromagnetic energy from the desired area even if that area lies outside the input field of view130and the input angle β (beta).

As shown inFIG.1, the optically powered surface150may have a curvature. The curvature may be constant, such that the optically powered surface150forms part of a circle. The curvature may be variable, such that the optically powered surface150has a varying radius of curvature R. The optically powered surface150may have a curvature that is constant over a portion of the optically powered surface150and variable over another portion of the optically powered surface150. The optically powered surface150may be convex, as shown inFIG.1. Alternatively, the optically powered surface150may be concave. The optically powered surface150may be reflective (e.g., the optically powered surface150may be mirrored). Alternatively, the optically powered surface150may be transmissive (e.g., the optically powered surface150may allow passage of electromagnetic energy while “bending” the electromagnetic energy as a lens). The optically powered surface150may include a plurality of planar portions, with each of the planar portions being angularly offset from others of the plurality of planar portions.

According to one implementation, the apparatus100may be used to analyze electromagnetic energy. The method may include redirecting electromagnetic energy160(shown as dashed lines, two of which are illustrated and identified) within the redirected field of view152of the optically powered surface150with the optically powered surface150onto the optical path117that passes through the input surface104of the substrate102. The method may further include, after redirecting the electromagnetic energy160, reflecting the electromagnetic energy160off of the plurality of reflective surfaces122positioned within the substrate102.

The method may further include, after reflecting the electromagnetic energy160off of the plurality of reflective surfaces122, separating various components of the electromagnetic energy160(e.g., by passing the electromagnetic energy160through the output optic110).

Referring toFIG.2, the apparatus100may include an intermediate reflective surface162(e.g., a linear, planar, mirror) positioned between the input surface104of the substrate102and the optically powered surface150with respect to the optical path117so as to redirect electromagnetic energy that has been redirected by the optically powered surface150through the input surface104. The intermediate reflective surface162may be supported at an angle Δ (delta) with respect to the plane P1.

As shown, the apparatus100may include a substrate102with the input angle β (beta) and the input angle λ (lambda) being equal, (e.g., 90° as shown in the illustrated embodiment). Thus, the intermediate reflective surface162and the optically powered surface150cooperatively change the size of the field of view within which electromagnetic energy can be collected and directed to the detector116, while the input angle for the electromagnetic energy remains the same. According to one embodiment, the angle Δ (delta) may be about 60°, thus changing the angle β′ (beta prime) of the optical path117from about 90° to about 30°, at which the optical path117intersects the optically powered surface150.

Referring toFIG.3, the apparatus100may include the intermediate reflective surface162positioned within the redirected field of view152of the optically powered surface150so as to redirect electromagnetic energy into the redirected field of view152and toward the optically powered surface150where the electromagnetic energy is then redirected through the input surface104and into the substrate102along the optical path117. Thus, the optically powered surface150provides an increased field of view which is then redirected to an input angle λ′ (lambda prime) by the intermediate reflective surface162.

The intermediate reflective surface162may include a reflective film (e.g., on an exterior surface of the substrate102). Such an arrangement may be beneficial for use in an integrated sensing platform, or a system on a chip. The intermediate reflective surface162may be a functional surface, an indicator, or a microfluidic structure.

Referring toFIGS.1to4, the optically powered surface150may be shaped to determine whether the redistribution of the input field of view130to the redirected field of view152is uniform or non-uniform. In a uniform redistribution (e.g., as shown inFIG.2), the density of rays of the electromagnetic energy160that reflect off of the optically powered surface150, into the input field of view130, and through the input surface104, are evenly spaced. In a non-uniform redistribution (e.g., as shown inFIG.4), the density of rays of the electromagnetic energy160that reflect off of the optically powered surface150, into the input field of view130, and through the input surface104, are unevenly spaced. A non-uniform distribution may be an intentional design feature or it may be the result of approximating a uniform redistributing reflector shape (e.g., a shape with a varying radius of curvature) with a more easily manufactured shape (e.g., a shape with a constant radius of curvature).

Referring toFIG.4, the radius of curvature R of the optically powered surface150may be constant, such that the optically powered surface150forms part of a circle164. As shown, the curvature of the optically powered surface150may result in a non-uniform redistribution (e.g., the rays of the electromagnetic energy160to the right of the redirected field of view152being are closer together than the rays of the electromagnetic energy160to the left of the field of view152).

Referring toFIG.5, the apparatus100may include a non-uniform redistribution that forms blind spots166within the field of view152. The blind spots166may be implemented in a manner that improves performance of the apparatus100by omitting regions on a measurement plane P2that do not contribute information to the measurement signal, or that present information whose omission or attenuation improves performance of the apparatus100. According to one implementation, the non-uniform redistribution may be used to adjust the contributions from different locations on the measurement plane P2with a significantly different response magnitude to the same excitation (e.g., measured fluorescence intensity). This balancing may enable collection of information from multiple locations, simultaneously.

As shown, the optically powered surface150may include a plurality of planar portions151a-c, with each of the planar portions151a-cbeing angularly offset from others of the plurality of planar portions151a-cso as to produce a non-uniform field of view152with one or more blind spots166. The apparatus100may include a lab-on-a-chip170that includes multiple, discrete sensing surfaces172a-c. Use of the discrete sensing surfaces172a-cmay be beneficial in preventing unwanted physical mixing of sensing components.

The apparatus100may further include an electromagnetic energy source174(e.g., a light source). According to one implementation, the apparatus100may include the intermediate reflective surface162. The intermediate reflective surface162may be positioned so as to reflect electromagnetic energy160from the electromagnetic energy source174to one of the discrete sensing surfaces172a-c, where the electromagnetic energy160is then reflected to the optically powered surface150, before being redirected into the input field of view130and through the input surface104.

Thus, according to one implementation, the apparatus100may collect electromagnetic energy160from more than one path. For example, a first ray160aof the electromagnetic energy160may travel from the electromagnetic energy source174directly to one of the discrete sensing surfaces172a-c, and then to the optically powered surface150to be redirected into the input field of view130and through the input surface104. A second ray160bof the electromagnetic energy160may travel from the electromagnetic energy source174to the intermediate reflective surface162, which may be a functional surface that performs a modification to the electromagnetic energy160, the second ray160breflects off of the intermediate reflective surface162to one of the discrete sensing surfaces172a-c, and then to the optically powered surface150to be redirected into the input field of view130and through the input surface104.

Referring toFIGS.1to6, the optically powered surface150may redirect the majority up to an entirety of the electromagnetic energy160from the redirected field of view152to the input field of view130. However, it may be advantageous to at least partially preserve the electromagnetic energy160. One example of an advantageous application of the preserved electromagnetic energy is in the use of “stacked” (or multiple) field of view redistributions. Another potential advantage is in dual use scenarios (e.g., measuring light reflected from a scene and also measuring the light from the ambient lighting illuminating the scene.

As shown inFIG.6, the optically powered surface150of the apparatus100may redirect a first portion161aof the electromagnetic energy160from the redirected field of view152to the input field of view130and the optical path117, and while redirecting a second portion161bof the electromagnetic energy160from the redirected field of view152away from the input surface104. According to one implementation, the optically powered surface150may be partially silvered. The optically powered surface150may be concave, as shown in the illustrated embodiment. According to one embodiment, the optically powered surface150may be convex. Thus, the optically powered surface150may be reflective, refractive, or both reflective and refractive.

According to one implementation, the redirected field of view152of the optically powered surface150is smaller than the input field of view130of the apparatus102. The smaller field of view152may provide an advantage in applications where the distance to the measurement plane is unknown. The angular width θ (theta) of the field of view152, according to one embodiment, may be 0° (i.e., boundary lines176of the redirected field of view152are parallel). In an embodiment of the apparatus100in which the angular width θ (theta) of the redirected field of view152is a non-zero value, a size of a measurement spot increases as distance to the measurement spot increases. In an embodiment of the apparatus100in which the angular width θ (theta) of the redirected field of view152is zero, the size of the measurement spot remains constant even as distance to the measurement spot changes. A constant size for the measurement spot may be desirable in applications such as distinguishing an individual body temperature within a crowd of people.

Referring toFIGS.1to6, according to one implementation, a method of fabricating the apparatus100may include positioning the substrate102, which is transmissive of electromagnetic energy, such that the optical path117is established, wherein electromagnetic energy that enters the substrate along the optical path propagates within the substrate. The method may include positioning the optically powered surface150relative to the substrate102, such that the optically powered surface150intersects the optical path117, and the optically powered surface150redirects the electromagnetic energy160within the redirected field of view152of the optically powered surface150into the substrate102along the optical path117, wherein the angular width θ (theta) of the redirected field of view152is different than the angular width α (alpha) of the input field of view130.

The above description of illustrated embodiments, including what is described in the Abstract, is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Although specific embodiments of and examples are described herein for illustrative purposes, various equivalent modifications can be made without departing from the spirit and scope of the disclosure, as will be recognized by those skilled in the relevant art.

Many of the methods described herein can be performed with variations. For example, many of the methods may include additional acts, omit some acts, and/or perform acts in a different order than as illustrated or described.

The various implementations and embodiments described above can be combined to provide further embodiments. For example, any of the characteristics of any embodiment of the optically powered surface150may be combined with any other embodiment of the optically powered surface150(e.g., a convex shaped embodiment of the optically powered surface150may be reflective, refractive, or both reflective and refractive, or a curved embodiment of the optically powered surface150may be used to form the redirected field of view152with the blind spots166).

To the extent that they are not inconsistent with the specific teachings and definitions herein, all of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, including but not limited to U.S. Pat. No. 10,656,013, issued on May 19, 2020; U.S. Publication No. 2019/0353522, published on Nov. 21, 2019; and U.S. Patent Application No. 63/088,278, filed on Oct. 6, 2020, are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary, to employ systems, circuits and concepts of the various patents, applications and publications to provide yet further embodiments.