WO2025235705A1

WO2025235705A1 - Polarized light detector and emitter based on sub-wavelength wire and wire grid

Info

Publication number: WO2025235705A1
Application number: PCT/US2025/028308
Authority: WO
Inventors: Stanley Pau
Original assignee: University of Arizona
Current assignee: University of Arizona
Priority date: 2024-05-10
Filing date: 2025-05-08
Publication date: 2025-11-13
Anticipated expiration: 2026-11-10

Abstract

Systems and devices for detection and generation of polarized light are described. The described devices can be configured to detect light with one or more polarization states including light having linear, circular and elliptical polarization states. One example polarization detector includes two or more wires positioned to receive incident light. A first wire includes either an n-doped or a p-doped semiconductor material, a second wire can be a metal wire or can include an n-doped or a p-doped semiconductor material. The wires are in contact with one another and form one or more depletion regions when reverse biased. A portion of the incident light with a polarization state that matches geometrical characteristics of the wires is absorbed, and a portion of light with a polarization state that does not match the geometrical characteristics of the wires is transmitted through the wires.

Description

POLARIZED LIGHT DETECTOR AND EMITTER BASED ON SUB-WAVELENGTH WIRE AND WIRE GRID

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to the provisional application with serial number 63/645,297 titled “POLARIZED LIGHT DETECTOR AND EMITTER BASED ON SUB-WAVELENGTH WIRE AND WIRE GRID,” filed May 10, 2024. The entire contents of the above noted provisional application are incorporated by reference as part of the disclosure of this document.

TECHNICAL FIELD

[0002] The technology described in this patent document relates to methods and systems for detection and generation of polarized light.

BACKGROUND

[0003] Conventional polarization sensitive detectors use a polarizer in front of a sensor. The polarizer absorbs part of the signal and transmits polarized light to a photodetector. The photodetector converts the light into a current which is measured and digitized into a signal that is proportional to the intensity of the incoming light. On average, if the incoming light is unpolarized, half of the light is lost in the detection process. It is beneficial to improve polarized light generation and detection.

SUMMARY

[0004] The disclosed embodiments relate to improved design methods and systems for detection and generation of polarized light. The polarization state of the light can be linear, circular and elliptical. Polarized light detection has applications in industrial metrology, surveillance, remote sensing, microscopy and medical imaging, where the image contrast is low and there is a strong background of unpolarized light. The disclosed sensors can uncover hidden signals and improve clarity for both color and monochromatic imaging. Polarized light generation has applications in three- dimensional (3D) display where stereoscopic images can be displayed using orthogonal polarized light and in optical metrology where polarized light source is used for illumination. [0005] An example polarization detector includes two or more wires positioned to receive incident light. A first wire of the two or more wires comprises either an n-doped or a p-doped semiconductor material, a second wire of the two or more wires comprises either a metal wire or (a) an n-doped semiconductor material if the first wire comprises the p-doped semiconductor material, or (b) a p-doped semiconductor material if the first wire comprises the n-doped semiconductor material, each of the first and the second wires has a width that is smaller than a wavelength of the incident light, the two or more wires are in contact with one another and form one or more depletion regions when reverse biased such that electron-hole pairs are generated in response to receiving the incident light, and wherein a portion of the incident light with a polarization state that matches geometrical characteristics of the two or more wires is absorbed by the two or more wires, and a portion of light with a polarization state that does not match the geometrical characteristics of the two or more wires is transmitted through the two or more wires.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG 1 illustrates a polarized light detector that includes a p-type semiconductor wire connected to an n-type semiconductor wire in accordance with an example embodiment.

[0007] FIG. 2 illustrates a polarized light detector that includes a p-type semiconductor wire and an n-type semiconductor wire in accordance with an example embodiment.

[0008] FIG. 3 illustrates a polarized light detector that includes a p-type semiconductor wire, an intrinsic semiconductor wire and a n-type semiconductor wire in accordance with an example embodiment.

[0009] FIG. 4 illustrates a polarized light detector that includes a p+ type semiconductor wire, an intrinsic semiconductor wire, a p type semiconductor wire, and an n+ type semiconductor wire in accordance with an example embodiment.

[0010] FIG. 5 illustrates an array of semiconductor wires of sub-wavelength dimension in accordance with an example embodiment.

[0011] FIG. 6 illustrates another array of semiconductor wires of sub-wavelength dimension in accordance with an example embodiment. [0012] FIG. 7 illustrates a polarized light detector that includes an array of wires that can detect light of two different polarization states in accordance with an example embodiment.

[0013] FIG. 8 illustrates another polarized light detector that includes an array of wires that can detect light of two different polarization states in accordance with an example embodiment.

[0014] FIG. 9 illustrates a polarized light detector configured to detect circularly polarized light and includes a p-type semiconductor wire and an n-type semiconductor wire in accordance with an example embodiment.

[0015] FIG. 10 illustrates a polarized light detector that includes two spiral shaped wires shaped adapted to detect light of two different circular polarization states in accordance with an example embodiment.

[0016] FIG. 11 illustrated a polarized light detector configured to detect elliptically polarized light and includes a p-type semiconductor spiral wire on top of an n-type semiconductor spiral wire in accordance with an example embodiment.

[0017] FIG. 12 illustrates a set of polarized light detectors configured to detect different linear polarization states in accordance with an example embodiment.

[0018] FIG. 13 illustrates a set of polarized light detectors configured to detect different linear and circular polarization states in accordance with an example embodiment.

[0019] FIG. 14 illustrates a cross-sectional diagram of a conventional polarization sensitive pixel.

[0020] FIG. 15 illustrates a cross-sectional diagram of a polarization sensitive pixel in accordance with an example embodiment.

[0021] FIG. 16 illustrates a cross-sectional diagram of a display pixel using a polarized light emitter junction in accordance with an example embodiment.

DETAILED DESCRIPTION

[0022] Conventional polarization sensitive detectors use a polarizer in front of a sensor. The polarizer absorbs part of the signal and transmits polarized light to a photodetector. The photodetector converts the light into a current which is measured and digitized into a signal that is proportional to the intensity of the incoming light. On average, if the incoming light is unpolarized, half of the light is lost in the detection process. The disclosed embodiments, among other features and benefits, describe a photodetector that absorbs one state of polarized light and transmits the orthogonal state of polarized light which can be subsequently detected by a second photodetector. On average, if the incoming light is unpolarized, all of the light is detected in this detection process.

[0023] Important characteristics of light include its intensity, wavelength, , and polarization. Light can have a range of wavelengths and polarization states. The spectrum of light provides a distribution of intensity for different wavelengths. Polarization can be described by the four-component Stokes parameters. The Stokes parameters can be measured by using different polarizers and photodetectors. For many applications, light with visible wavelength is used, and the wavelength can range from 400nm to 700nm.

[0024] In one embodiment, the basic unit of the polarized light detector is a semiconductor wire of sub-wavelength dimension. The width and height of the wire can be in the range 0.1/Vn to 0.8 /n, where n is the refractive index of the semiconductor close to the detection wavelength. In some embodiments, the dimension can be smaller than 0.1>\/n, but smaller dimensions can lead to reduced active volume for light detection. It should be noted that the term “wire” is used in this document to convey the elongate shape of the semiconductor material, which can have a rectangular, square, or other cross-sectional shapes.

[0025] FIG. 1 shows an example polarized light detector 100 that includes a p-type semiconductor wire 102 connected to an n-type semiconductor wire 103. The wires 102 and 103 are reversed biased to create a depletion region in the wires. Incoming light 110 is absorbed by the wires and generates electron and hole pairs. The electron-hole pairs are separated in the depletion region and can be measured by an external circuit (not shown) connected to the pads 101 and 104. The detector 100 is sensitive to light that is linearly polarized in the direction parallel to the wire. Light that is linearly polarized in the direction perpendicular to the wire is not absorbed and passes through the detector.

[0026] In one embodiment, the basic unit of the polarized light detector is two overlapping semiconductor wires of sub-wavelength dimension. The width and height of the two wires can range 0.1 Ain to Q.8Aln, where n is the refractive index of the semiconductor at or close to the detection wavelength. FIG. 2 shows an example polarized light detector 200, including a p-type semiconductor wire 203 on top of an n- type semiconductor wire 202. The wires 202 and 203 are reversed biased to create a depletion region in the wires. Incoming light 210 is absorbed by the wires and generates electron and hole pairs. The electron and hole pairs are separated in the depletion region and can be measured by an external circuit (not shown) connected to the pads 201 and 204. The detector 200 is sensitive to light that is linearly polarized in the direction parallel to the wire. Light that is linearly polarized in the direction perpendicular to the wire is not absorbed and passes through the detector. In other embodiments, the polarized light detector 200 can be made of a doped semiconductor wire 203 on top of a metal wire 202. The two wires form a metal-semiconductor junction diode that can be used to detect light. [0027] In another embodiment, the basic unit of the polarized light detector is three overlapping semiconductor wires of sub-wavelength dimension. The width and height of the three wires can range 0.1 Ain to 0.8 //?, where n is the refractive index of the semiconductor close to the detection wavelength. FIG. 3 shows an example polarized light detector 300, including a p-type semiconductor wire 303 on top of an intrinsic semiconductor wire 304 and a n-type semiconductor wire 302. The wires 302, 303 and 304 form a p-i-n junction and are reversed biased to create a depletion region in the wires. Incoming light 310 is absorbed by the wires and generates electron and hole pairs. The electron and hole pairs are separated in the depletion region and can be measured by an external circuit (not shown) connected to pads 301 and 305. The detector 300 is sensitive to light that is linearly polarized in the direction parallel to the wire. Light that is linearly polarized in the direction perpendicular to the wire is not absorbed and passes through the detector.

[0028] In another embodiment, the basic unit of the polarized light detector is four overlapping semiconductor wires of sub-wavelength dimension. The width and height of the three wires can range 0.14/n to 0.8 /r?, where n is the refractive index of the semiconductor close to the detection wavelength. FIG. 4 shows a polarized light detector 400, including a p+ type semiconductor wire 403 on top of an intrinsic semiconductor wire 404, p type semiconductor wire 405, and an n+ type semiconductor wire 402. The wires 402, 403, 404 and 405 are reversed biased to create a depletion region in the wires and form a n+-p-m-p+ junction, which is a type of avalanche photodiode. The junction has separate absorption and multiplication regions. The symbol TT represents the intrinsic or lightly doped semiconductor region. Incoming light 410 is absorbed by the TT region in the wires and generates electron and hole pairs. The electron and holes pairs are separated and can be measured by an external circuit (not shown) connected to the pads 401 and 405. The detector 400 is sensitive to light that is linearly polarized in the direction parallel to the wire. Light that is linearly polarized in the direction perpendicular to the wire is not absorbed and passes through the detector. For those skill in the art of semiconductor photo detector design, a different photo detector can be designed within the scope of the disclosed embodiments by stacking wires of different dopants to form a semiconductor junction. As one example, the four wires embodiment 400 can be made of a p+-n-rr-n+ junction. The junction can also operate as a single-photon avalanche diode (SPAD) with application of a high reverse bias.

[0029] By nature of the shape of the wires, the detection volume of photo detector in FIG. 1 to FIG. 4 is small. The detection volume of the photo detector can be augmented by stacking the wire detector in an array or grid. FIG. 5 shows an array of semiconductor wires 100 with sub-wavelength dimensions. The polarized light detector 500, including an array of p-type semiconductor wires 502 connected to (and facing) an array of n-type semiconductor wires 503. The two wire arrays 502 and 503 are reverse biased to create a depletion region in the wires. Incoming light is absorbed by the wires and generates electron and hole pairs. The electron and hole pairs are separated in the depletion region and can be measured by an external circuit (not shown) connected to pads 501 and 504. The detector 500 is sensitive to light that is linearly polarized in the direction parallel to the wire. Light that is linearly polarized in the direction perpendicular to the wire is not absorbed and passes through the detector. In this embodiment, the duty cycle, i.e., the width of the wire to the empty space between two individual adjacent wires, for the device 500 is 1 :1 . In other embodiments, the duty cycle can range from 1 :0.2 to 1 :10.

[0030] FIG. 6 shows another embodiment of an array of semiconductor wire 200 of sub-wavelength dimension. The polarized light detector 600, including an array of p-type semiconductor wires 602 connected to (and positioned on top of) an array of n-type semiconductor wires 603. The two wire arrays 602 and 603 are reverse biased to create a depletion region in the wires. Incoming light is absorbed by the wires and generates electron and hole pairs. The electron and holes pairs are separated in the depletion region and can be measured by an external circuit (not shown) connected to the pads 601 and 604. The detector 600 is sensitive to light that is linearly polarized in the direction parallel to the wire. Light that is linearly polarized in the direction perpendicular to the wire is not absorbed and passes through the detector. In some embodiments, the duty cycle of detector 600 can range from 1 :0.2 to 1 :10.

[0031] The different embodiments of the disclosed detectors have the advantage of detecting light of one polarization state while transmitting light of the orthogonal polarization state. FIG. 7 shows an embodiment of a polarized light detector 700 that includes an array of wires and can detect light of two different polarization states. Two detectors, 701 and 702, are stacked on top of each other to form a polarized light detector. The wires in each detector 701 , 702 are configured similar to those in FIG. 5. Incoming light having different polarization states is first detected by 701 and subsequently by 702. FIG. 8 shows another embodiment of a polarized light detector 800 that includes an array of wires and can detect light of two different polarization states. Two detectors, 801 and 802, are stacked on top of each other to form a polarized light detector. The wires in each detector 801 , 802 are configured similar to those in FIG. 6. In this embodiment, the two detectors are oriented to detect orthogonal polarization states. In other embodiments, the two detectors can be oriented to detect polarization states that are not orthogonal to each other. In yet other embodiments, there can be more than two detectors, i.e., three or more detectors, stacking on top of each other. The detectors 801 and 802 can be separated by a planar retarder layer (not shown), such that incoming light is first partially absorbed by 801 , passes through a retarder layer and then absorbed by 802.

[0032] The polarized light detector can be generalized to detection of circular polarized light. In one embodiment, the basic unit of the polarized light detector includes two overlapping semiconductor wires of sub-wavelength dimension. The width and height of the two wires can range 0.1 Ain to 0.8Aln, where n is the refractive index of the semiconductor close to the detection wavelength. FIG. 9 shows an example polarized light detector 900, including a p-type semiconductor wire 901 on top of an n-type semiconductor wire 902. The wires 902 and 903 have the shape of a circular spiral and are reverse biased to create a depletion region in the wires. Incoming light is absorbed by the wires which generate electron and hole pairs. The detector 900 is sensitive to light that is right hand circularly polarized if the incident light is coming from top to bottom. Light that is left hand circularly polarized is not absorbed and passes through the detector. [0033] The polarized light detector 900 can be stacked to detect light of the orthogonal circular polarization state. FIG. 10 shows an embodiment of a polarized light detector 1000 that includes two wires shaped as spirals (similar to FIG. 9) but in two different directions. The detector 1000 can detect light of two different circular polarization states. Two detectors, 1001 and 1002, are stacked on top of each other to form a polarized light detector. Incoming light with different polarization states is first detected by 1001 and subsequently by 1002.

[0034] The polarized light detector can be adapted to detect ell iptically polarized light. In one embodiment, the basic unit of the polarized light detector includes again two overlapping semiconductor wires of sub-wavelength dimension. FIG. 11 shows an example polarized light detector 1100, including a p-type semiconductor wire on top of an n-type semiconductor wire. The wires have the shape of an elliptical spiral and are reverse biased to create a depletion region in the wires. Incoming light is absorbed by the wires, which generate electron and hole pairs. One detector 1101 is sensitive to light that is right hand elliptically polarized if the incident light is coming from top to bottom. The polarized light detector 1100 can be constructed using two sets of wires 1101 and 1102 and can detect light of two different elliptical polarization states. For example, 1101 is used to detect right hand elliptically polarized light and 1102 is used to detect left handed elliptical polarized light of a different direction.

[0035] As seen from the different embodiments of polarized light detectors 600, 900, 1101 and 1102, the sub-wavelength semiconductor wires 100 and 200 can be designed to have a shape and an orientation matching the shape and orientation of the path of the electric field of the polarized light, such as linear, circular and elliptical.

[0036] The polarized light detector can be assembled to form a two-dimensional focal plane array for polarization imaging applications. FIG. 12 shows an example unit set 1200 of four polarized light detectors. Detector 1201 is sensitive to light that is linearly polarized at 45 degrees. Detector 1202 is sensitive to light that is linearly polarized at 90 degrees. Detector 1203 is sensitive to light that is linearly polarized at 0 degree. Detector 1204 is sensitive to light that is linearly polarized at -45 degrees. In the example unit set 1200 of FIG. 12, each detector includes a set of two wires that are stacked on top of each other (similar to FIGS. 2 or 6). The unit set 1200 can be repeated to form a larger array of periodic detectors. In another embodiment, shown in FIG. 13, a unit set 1300 includes another four polarized light detectors. Detector 1301 is sensitive to light that is linearly polarized at -45 degrees. Detector 1302 is sensitive to light that is circular polarized. Detector 1303 is sensitive to light that is circular polarized at a different chirality. Detector 1304 is sensitive to light that is linearly polarized at 0 degrees. In other embodiments, the detector 1300 can be stacked similar to that shown in FIG. 10 and FIG. 11. Different polarized detectors can be assembled, stacked and tiled in various configurations to detect polarization images. Several optimal configurations are discussed in a paper by Tu et al. (X. Tu and S. Pau, “Optimized design of N optical filters for color and polarization imaging,” Opt. Express 24(3), 3011-3024 (2016)).

[0037] The cross-section of a conventional polarization sensitive pixel 1400 in a focal plane array is shown in FIG. 14. The pixel includes a microlens 1401 , which may have an anti-reflection coating, a color filter 1402, a polarizer 1403, a photo diode 1404, barrier regions 1405, an electronic interconnect layer 1406 and a circuit layer 1407. In comparison, the cross-section of a polarization sensitive pixel 1500 based on the disclosed embodiments is shown in FIG. 15. The pixel includes a microlens 1501 , which may have an anti-reflection coating, a color filter 1502, a retarder 1503, a polarized light detector 1504, a second polarized light detector 1505, barrier regions 1506, an electronic interconnect layer 1507 and a circuit layer 1508. In some embodiments, the polarized light detectors 1504 and 1505 can be the polarized light detector 700, 800, 1000 or 1100. [0038] For those skilled in the art of semiconductor fabrication and processing, the polarized light detector described herein can be fabricated using standard micro- and nano-fabrication techniques utilized extensively in the manufacturing of semiconductor integrated circuits and other devices. Techniques may include optical lithography, wet and dry etching, and vacuum deposition of semiconductor, insulator and metal. The detector can be connected to dedicated on-chip integrated circuits to digitize, store and transmit the detected current signal for each detector. The gaps in between the wire detectors and layers of array detectors can be filled with transparent low loss isotropic material such as silicon dioxide or transparent low loss birefringent material such as liquid crystal or liquid crystal polymer. The signal current of different detectors can be separated by insulating layers to prevent signal crosstalk.

[0039] As mentioned earlier, conventional polarized light source uses a polarizer in front of a light emitter. The polarizer absorbs part of the emitted light and transmits polarized light. The light source emits unpolarized light. On average, half the light is lost in the light generation process. The p-n junction wire (such as the one shown in FIG. 2) can be made of direct bandgap semiconductors, such as GaAs, InGaAs, AlxGa1 -xAs (x<0.4), GaN, AIN, CdS, CdSe, CdTe, ZnS, PbS and PbSe. The junction can also be made of organic semiconductors such as perylenetetracarboxylic dianhydride (PTCDA), pentacene, perylene, quarter-thiophene, triphenylene and others. If the junction is forward biased, instead of reverse biased, electron and hole pairs are injected, and light is emitted when the electron and the hole combine. The light is linearly polarized in the direction parallel to the wire. In configurations shown in FIGS. 6, 9, 12 and 13, light of different polarization states can be generated. The light emitting junction can be connected and controlled individually by a circuit to form a programmable polarized light display. Array of pixels that emit different polarized light can be constructed to generate an image of different Stokes parameters.

[0040] FIG. 16 shows the cross-section of a display pixel 1600 using a polarized light emitter junction 1603, such as the device 600 of FIG. 6. The junction 1603 emits polarized light which passes through an optical filter layer 1602 that includes a color filter and/or optical retarder to a microlens 1601. The purpose of the microlens 1601 is to distribute the light to a predefined narrow or wide angular range, depending on the application. A reflector layer 1604, which may include a retarder layer and a mirror layer, can be used to direct back emitted light to the microlens. The display pixel is connected to an interconnect layer 1605 and a driver circuit layer 1606. The light emitter and circuit are positioned on top of an isolation layer 1607 on a substrate 1608. The substrate 1608 can be rigid or flexible.

[0041] One aspect of the disclosed embodiments relates to a polarization detector that includes two or more wires positioned to receive incident light. A first wire of the two or more wires comprises either an n-doped or a p-doped semiconductor material, a second wire of the two or more wires comprises either a metal wire or (a) an n-doped semiconductor material if the first wire comprises the p-doped semiconductor material, or (b) a p-doped semiconductor material if the first wire comprises the n-doped semiconductor material, each of the first and the second wires has a width that is smaller than a wavelength of the incident light, the two or more wires are in contact with one another and form one or more depletion regions when reverse biased such that electronhole pairs are generated in response to receiving the incident light, and wherein a portion of the incident light with a polarization state that matches geometrical characteristics of the two or more wires is absorbed by the two or more wires, and a portion of light with a polarization state that does not match the geometrical characteristics of the two or more wires is transmitted through the two or more wires.

[0042] In one example embodiment, the two or more wires are each formed as a straight wire, and allow a linearly polarized light with a first polarization angle to be absorbed and a linearly polarized light with a second polarization angle to pass through. In another example embodiment, the two or more wires are configured as a first wire pair, and a first end of the first wire is in contact with a first end of the second wire such that a depletion region of the one or more depletion regions is formed at or around a region of contact between the first ends of the first and second wires in response to receiving the incident light. In yet another example embodiment, the two or more wires are configured as an array of wire pairs that include the first wire pair and additional wire pairs, each additional wire pair comprises two wires that comprise either a metal wire, an n-doped semiconductor material or a p-doped semiconductor material, each of the two wires of each additional wire pair contact one another at an end, and each wire pair in the array of wire pairs is positioned in parallel with all other wire pairs in the array of wire pairs. In still another example embodiment, the array of wire pairs is a first array, the polarization detector includes a second array having wire pairs configured identically as the first array, and the second array is positioned behind the first array to receive light that is transmitted through the first array, and the second array is positioned at a non-zero angle with respect to the first array to absorb light that is linearly polarized light with the second polarization angle.

[0043] According to another example embodiment, the two or more wires are configured as a first wire pair, and a first surface of the first wire along a longitudinal direction of the first wire is in contact with a first surface of the second wire along the longitudinal direction such that a depletion region of the one or more depletion regions is formed at or around a region of contact between the first surfaces of the first and second wires in response to receiving the incident light. In one example embodiment, the two or more wires are configured as an array of wire pairs that include the first wire pair and additional wire pairs, each additional wire pair comprises two wires that comprise either a metal wire, an n-doped semiconductor material or a p-doped semiconductor material, each of the two wires of each additional wire pair contacting each other along a longitudinal direction of the two wires, and each wire pair in the array of wire pairs is positioned in parallel with all other wire pairs in the array of wire pairs. In yet another example embodiment, the array of wire pairs is a first array, the polarization detector includes a second array having wire pairs configured identical to the first array, and the second array is positioned behind the first array to receive light that is transmitted through the first array, and the second array is positioned at a non-zero angle with respect to the first array to absorb light that is linearly polarized light with the second polarization angle. [0044] In another example embodiment, the first wire comprises the n-doped semiconductor material, the second wire comprises the p-doped semiconductor material, and the two or more wires comprise a first wire set that includes the first wire, the second wire and a third wire that forms an intrinsic layer or region, and the third wire is positioned between the first and second wires such that one surface of the third wire in longitudinal direction is in contact with one surface of the first wire in longitudinal direction, and another surface of the third wire in longitudinal direction is in contact with one surface of the second wire in longitudinal direction. In still another example embodiment, the two or more wires are configured as an array of wire sets that include the first wire set and additional wire sets, each additional wire set comprises three wires that consist of one n- doped material, one p-doped material and one material forming an intrinsic layer or region, each of the three wires contacting another of the three wires along a longitudinal surface of each wire, and each wire set in the array of wire sets is positioned in parallel with all other wire sets in the array of wire sets.

[0045] In one example embodiment, the two or more wires comprise a wire set that includes the first wire, the second wire and one or more additional wires that are doped, undoped, or comprise a metal wire, and the one or more additional wires are positioned such that one surface each of the one or more additional wires in longitudinal direction is in contact with one surface of (a) another one of the one or more additional wires in longitudinal direction, or (b) with one surface of the first or the second wire in longitudinal direction. In another example embodiment, the one or more additional wires is (a) undoped, (b) has a p+ doping, or (c) has an n+ doping.

[0046] In another example embodiment, the first and second wires form a first wire pair, each of the first and second wires has a circular spiral shape having a first handedness, and one surface of the first wire is in contact with one surface of the second wire along the circular spiral shape, and the first wire pair allows a circularly polarized light with the first handedness to be absorbed and a circularly polarized light with a second handedness to pass through the first wire pair. In yet another example embodiment, the polarization detector includes a second wire pair including two wires each configured as a circular spiral with the second handedness and in contact with each other on one surface along the circular spiral of the second wire pair, and the second wire pair is positioned behind the first wire pair to receive and absorb the circularly polarized light with the second handedness.

[0047] According to another example embodiment, the first and second wires form a first wire pair, each of the first and second wires has an elliptical spiral shape having a first handedness and a first ellipticity, and one surface of the first wire is in contact with one surface of the second wired along the elliptical spiral shape, and the first wire pair allows a first elliptically polarized light to be absorbed and elliptically polarized light orthogonal to the first elliptically polarized light to pass through the first wire pair. In one example embodiment, the polarization detector includes a second wire pair including two wires each configured as an elliptical spiral with a second handedness or ellipticity, the two wires of the second wire pair are in contact with each other on one surface along the elliptical spiral of the second wire pair, and the second wire pair is positioned behind the first wire pair to receive and absorb elliptically polarized light with the second handedness or ellipticity.

[0048] In another example embodiment, the polarization detector is a first polarization detection unit that is part of a polarization detector array comprising one or more additional polarization detection units, each of the one or more additional polarization detection units comprises a plurality of wires shaped to allow a particular polarization state of incident light to be absorbed, at least two of the plurality of wires in each additional polarization detection unit is in contact with each other along one surface thereof, and all polarization detection units are positioned on a same plane to simultaneously receive the incident light. In yet another example embodiment, the polarization detector array includes four polarization detection units, and each polarization unit is shaped to detect a state of polarization that is different from polarization states detectable by other polarization detection units in the polarization detector array. In still another example embodiment, the polarization detector array includes four polarization detection units to allow detection of linear and circular polarization states.

[0049] In one example embodiment, the polarization detector is implemented as part of a polarization sensitive detection pixel that includes: a microlens, and a color filter to allow a particular wavelength to pass through and reach the polarization detector.

[0050] Another aspect of the disclosed embodiments relates to a polarized light source that includes a polarized light emitter junction comprising two or more wires, wherein a first wire of the two or more wires comprises either an n-doped or a p-doped semiconductor material, a second wire of the two or more wires comprises either a metal wire or (a) an n-doped semiconductor material if the first wire comprises the p-doped semiconductor material, or (b) a p-doped semiconductor material if the first wire comprises the n-doped semiconductor material, each of the first and the second wires has a width that is smaller than a wavelength of polarized light to be generated by the polarized light source, and the two or more wires are in contact with one another such that, when the polarized light emitter junction is forward biased, electron-hole pairs are combined to generate the polarized light that matches geometrical characteristics of the two or more wires.

[0051] In one example embodiment, the polarized light emitter junction is a first polarized emitter junction that is implemented as part of a first pixel in a pixel array, and wherein the first pixel further includes a color filter or an optical retarder, a microlens, and a back reflector array. In another example embodiment, each pixel in the pixel array includes a corresponding polarized light emitter junction that is configured to generate polarized light with a particular polarization. In yet another example embodiment, each pixel is individually controllable by an electrical circuit.

[0052] Various components may be controlled, or various operations may be performed via implementations using a processor/controller that is configured to include, or be coupled to, a memory that stores processor executable code that causes the processor/controller carry out various computations and processing of information. The processor/controller can further generate and transmit/receive suitable information to/from the various system components, as well as suitable input/output (IO) capabilities (e.g., wired or wireless) to transmit and receive commands and/or data. The processor/controller may, for example, provide signals to control the operation of various components such as light sources, power supplies and detectors that are disclosed herein.

[0053] Various information and data processing operations for controlling the operation of various devices such as light sources, power supplies and detectors and others described herein may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), cloud storage, etc. Therefore, the computer-readable media that is described in the present application comprises non- transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

[0054] Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.

Claims

CLAIMS WHAT IS CLAIMED IS:

1 . A polarization detector, comprising: two or more wires positioned to receive incident light, wherein: a first wire of the two or more wires comprises either an n-doped or a p-doped semiconductor material, a second wire of the two or more wires comprises either a metal wire or (a) an n- doped semiconductor material if the first wire comprises the p-doped semiconductor material, or (b) a p-doped semiconductor material if the first wire comprises the n-doped semiconductor material, each of the first and the second wires has a width that is smaller than a wavelength of the incident light, the two or more wires are in contact with one another and form one or more depletion regions when reverse biased such that electron-hole pairs are generated in response to receiving the incident light, and wherein a portion of the incident light with a polarization state that matches geometrical characteristics of the two or more wires is absorbed by the two or more wires, and a portion of light with a polarization state that does not match the geometrical characteristics of the two or more wires is transmitted through the two or more wires.

2. The polarization detector of claim 1 , wherein the two or more wires are each formed as a straight wire, and allow a linearly polarized light with a first polarization angle to be absorbed and a linearly polarized light with a second polarization angle to pass through.

3. The polarization detector of claim 2, wherein the two or more wires are configured as a first wire pair, and a first end of the first wire is in contact with a first end of the second wire such that a depletion region of the one or more depletion regions is formed at or around a region of contact between the first ends of the first and second wires in response to receiving the incident light.

4. The polarization detector of claim 3, wherein the two or more wires are configured as an array of wire pairs that include the first wire pair and additional wire pairs, each additional wire pair comprises two wires that comprise either a metal wire, an n-doped semiconductor material or a p-doped semiconductor material, each of the two wires of each additional wire pair contact one another at an end, and each wire pair in the array of wire pairs is positioned in parallel with all other wire pairs in the array of wire pairs.

5. The polarization detector of claim 4, wherein: the array of wire pairs is a first array, the polarization detector includes a second array having wire pairs configured identically as the first array, and the second array is positioned behind the first array to receive light that is transmitted through the first array, and the second array is positioned at a non-zero angle with respect to the first array to absorb light that is linearly polarized light with the second polarization angle.

6. The polarization detector of claim 2, wherein: the two or more wires are configured as a first wire pair, and a first surface of the first wire along a longitudinal direction of the first wire is in contact with a first surface of the second wire along the longitudinal direction such that a depletion region of the one or more depletion regions is formed at or around a region of contact between the first surfaces of the first and second wires in response to receiving the incident light.

7. The polarization detector of claim 6, wherein the two or more wires are configured as an array of wire pairs that include the first wire pair and additional wire pairs, each additional wire pair comprises two wires that comprise either a metal wire, an n-doped semiconductor material or a p-doped semiconductor material, each of the two wires of each additional wire pair contacting each other along a longitudinal direction of the two wires, and each wire pair in the array of wire pairs is positioned in parallel with all other wire pairs in the array of wire pairs.

8. The polarization detector of claim 7, wherein: the array of wire pairs is a first array, the polarization detector includes a second array having wire pairs configured identical to the first array, and the second array is positioned behind the first array to receive light that is transmitted through the first array, and the second array is positioned at a non-zero angle with respect to the first array to absorb light that is linearly polarized light with the second polarization angle.

9. The polarization detector of claim 2, wherein: the first wire comprises the n-doped semiconductor material, the second wire comprises the p-doped semiconductor material, and the two or more wires comprise a first wire set that includes the first wire, the second wire and a third wire that forms an intrinsic layer or region, and the third wire is positioned between the first and second wires such that one surface of the third wire in longitudinal direction is in contact with one surface of the first wire in longitudinal direction, and another surface of the third wire in longitudinal direction is in contact with one surface of the second wire in longitudinal direction.

10. The polarization detector of claim 9, wherein the two or more wires are configured as an array of wire sets that include the first wire set and additional wire sets, each additional wire set comprises three wires that consist of one n-doped material, one p-doped material and one material forming an intrinsic layer or region, each of the three wires contacting another of the three wires along a longitudinal surface of each wire, and each wire set in the array of wire sets is positioned in parallel with all other wire sets in the array of wire sets.

11 . The polarization detector of claim 2, wherein: the two or more wires comprise a wire set that includes the first wire, the second wire and one or more additional wires that are doped, undoped, or comprise a metal wire, and the one or more additional wires are positioned such that one surface each of the one or more additional wires in longitudinal direction is in contact with one surface of (a) another one of the one or more additional wires in longitudinal direction, or (b) with one surface of the first or the second wire in longitudinal direction.

12. The polarization detector of claim 11 , wherein the one or more additional wires is (a) undoped, (b) has a p+ doping, or (c) has an n+ doping.

13. The polarization detector of claim 1 , wherein the first and second wires form a first wire pair, each of the first and second wires has a circular spiral shape having a first handedness, and one surface of the first wire is in contact with one surface of the second wire along the circular spiral shape, and the first wire pair allows a circularly polarized light with the first handedness to be absorbed and a circularly polarized light with a second handedness to pass through the first wire pair.

14. The polarization detector of claim 13, wherein: the polarization detector includes a second wire pair including two wires each configured as a circular spiral with the second handedness and in contact with each other on one surface along the circular spiral of the second wire pair, and the second wire pair is positioned behind the first wire pair to receive and absorb the circularly polarized light with the second handedness.

15. The polarization detector of claim 1 , wherein the first and second wires form a first wire pair, each of the first and second wires has an elliptical spiral shape having a first handedness and a first ellipticity, and one surface of the first wire is in contact with one surface of the second wired along the elliptical spiral shape, and the first wire pair allows a first elliptically polarized light to be absorbed and elliptically polarized light orthogonal to the first elliptically polarized light to pass through the first wire pair.

16. The polarization detector of claim 15, wherein: the polarization detector includes a second wire pair including two wires each configured as an elliptical spiral with a second handedness or ellipticity, the two wires of the second wire pair are in contact with each other on one surface along the elliptical spiral of the second wire pair, and the second wire pair is positioned behind the first wire pair to receive and absorb elliptically polarized light with the second handedness or ellipticity.

17. The polarization detector of claim 1 , wherein: the polarization detector is a first polarization detection unit that is part of a polarization detector array comprising one or more additional polarization detection units, each of the one or more additional polarization detection units comprises a plurality of wires shaped to allow a particular polarization state of incident light to be absorbed, at least two of the plurality of wires in each additional polarization detection unit is in contact with each other along one surface thereof, and all polarization detection units are positioned on a same plane to simultaneously receive the incident light.

18. The polarization detector of claim 17, wherein the polarization detector array includes four polarization detection units, and each polarization unit is shaped to detect a state of polarization that is different from polarization states detectable by other polarization detection units in the polarization detector array.

19. The polarization detector of claim 17, wherein the polarization detector array includes four polarization detection units to allow detection of linear and circular polarization states.

20. The polarization detector of claim 17, wherein the polarization detector is implemented as part of a polarization sensitive detection pixel that includes: a microlens, and a color filter to allow a particular wavelength to pass through and reach the polarization detector.

21 . A polarized light source, comprising: a polarized light emitter junction comprising two or more wires, wherein: a first wire of the two or more wires comprises either an n-doped or a p-doped semiconductor material, a second wire of the two or more wires comprises either a metal wire or (a) an n- doped semiconductor material if the first wire comprises the p-doped semiconductor material, or (b) a p-doped semiconductor material if the first wire comprises the n-doped semiconductor material, each of the first and the second wires has a width that is smaller than a wavelength of polarized light to be generated by the polarized light source, and the two or more wires are in contact with one another such that, when the polarized light emitter junction is forward biased, electron-hole pairs are combined to generate the polarized light that matches geometrical characteristics of the two or more wires.

22. The polarized light source of claim 21 , wherein the polarized light emitter junction is a first polarized emitter junction that is implemented as part of a first pixel in a pixel array, and wherein the first pixel further includes a color filter or an optical retarder, a microlens, and a back reflector array.

23. The polarized light source of claim 22, wherein each pixel in the pixel array includes a corresponding polarized light emitter junction that is configured to generate polarized light with a particular polarization.

24. The polarized light source of claim 23, wherein each pixel is individually controllable by an electrical circuit.