The present application is a U.S. National Stage patent application of International Patent Application No. PCT/US2015/027331, filed on Apr. 23, 2015, the benefit of which is claimed and the disclosure of which is incorporated herein by reference in its entirety.
Embodiments of present disclosure generally relates to optics and, more particularly, to a spectrally programmable memristor-based optical device and method.
In recent years, optical analysis techniques have been developed for a number of applications. Some of these techniques employ the use of a thin-film optical interference element, also known as a multivariate optical element (“MOE”). In general, these techniques optically interact electromagnetic radiation (e.g., from a sample) with the MOE, wherein the output reflects the measured intensity of the electromagnetic radiation. The measured intensity may then be utilized in a number of applications, such as, for example, sensors.
Historically, such thin-film optical elements have been designed and fabricated using alternating layers of high-index and low-index materials deposited on a substrate. Once the materials have been deposited on the substrate, however, the transmission/reflection/absorption functions of the thin-film optical element are fixed due to the fundamental nature of the design and fabrication process. Therefore, once the film stack has been deposited, its spectral properties cannot be changed.
Illustrative embodiments and related methods of the present disclosure are described below as they might be employed in a spectrally programmable memristor-based optical device. In the interest of clarity, not all features of an actual implementation or method are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. Further aspects and advantages of the various embodiments and related methods of the disclosure will become apparent from consideration of the following description and drawings.
As described herein, the present disclosure is directed to an optical device which uses a memristor element to create a spectrally programmable optical device. A memristor, or “memory resistor,” is a non-linear electrical component in which its resistance is related to the electrical voltage applied across it. In a generalized embodiment of the present disclosure, electromagnetic radiation optically interacts with a memristor element made of spectrally alterable material. An electromagnetic field is applied across the memristor element in order to alter its spectral properties. In turn, the spectral properties of the electromagnetic radiation optically interacting with the memristor element are also altered. This alteration in spectral properties allows the memristor to be “programmed” to achieve a variety of transmission/reflection/absorption functions. As a result, the memristor-based devices of the present disclosure may be utilized in a variety of applications, including, for example, multi-functional optical sensors.
As previously mentioned, thin-film optical elements have been designed and fabricated using alternating layers of high-index and low-index materials deposited on a substrate. The fundamental equations governing the transmission, reflection and absorption functions of thin-film optical elements are the Fresnel equations, derived from Maxwell's equations. The choice of materials is based on the application and the range of wavelengths of interest. As an example, for an infrared application, one might choose a-Si (Amorphous Silicon) as the high index material, SiO2 (Silicon-di-oxide) as the low index material and glass as the substrate. The fabrication methods typically include PVD (Physical Vapor Deposition such as, for example, electron-beam vacuum deposition, RF magnetron sputtering, etc.), CVD (Chemical Vapor Deposition, such as MOCVD, PECVD etc.), ALD (Atomic Layer Deposition), etc.
As also mentioned, illustrative embodiments of the present disclosure utilize spectrally programmable memristor elements. The memristor elements are non-linear electrical components relating electrical charge and magnetic flux. The fundamental equation that governs the linkage of electrical charge (q) and magnetic flux (Φ) is shown as:
dΦ=Mdq Eq.(1),
also known as the circuit theory equation for a memristor. In Equation 1, Φ is the magnetic flux, M is the resistance of the memristor, and q is the charge. Accordingly, this type of device shows relationship between the resistance and electrical voltage applied across the memristor element.
In certain embodiments, the metal/semiconductor interface can be fabricated using standard processing techniques, such as, for example, PVD, CVD or ALD. Semiconductor layer 16 is deposited with a high level of defects present in the crystal lattice of the material such that diffusion of metal ions can occur when electromagnetic radiation (e.g., an electrical voltage) is applied across the device via metal layer 18 and contacts 14. Selection of the metal, semiconductor, defect level, etc., will depend on the application and the range of wavelengths of interest.
Still referencing
As previously mentioned, memristor element 100 is comprised of a single pixel, but in other embodiments memristor element 100 may be comprised of a plurality of pixels.
Still referencing
Optical separation device 306 is any device used to separate electromagnetic radiation 310 into component wavelengths, such as, for example, a diffraction grating or spectral splitting element. A diffraction grating uses the principal of diffraction to split light into its component wavelengths, while a spectral splitting element uses refraction (such as prisms, for example) or can use specially designed bandpass filters or notch filters, ring resonators etc.
During operation of calibration system 300, optical separation element 306 splits electromagnetic radiation 310 into its individual component wavelengths 310CW. Each memristor element MR1 . . . MR4 in array 302 is fabricated such that each component wavelength 310CW enters at least one memristor element MR1 . . . MR4, whereby optically-interacted light 312 is produced. Each memristor element MR1 . . . MR4 is designed to correspond to the component wavelength using any variety of techniques. For example, in certain embodiments, the diffraction grating (when used as element 306), memristor array 302 and detector array 308 are aligned such that only one wavelength or a narrow range of wavelengths enters each memristor element MR1 . . . MR4 using, for example, nano scale positioners. Alternatively, once the light is split by the diffraction grating, waveguides may also be used to carry the split light into each memristor element MR1 . . . MR4. In the illustrated example, optical separation device 306 transmits only one wavelength to each memristor element MR1 . . . MR4. In other examples, however, more than one wavelength or a narrow wavelength range may be transmitted.
In order to calibrate memristor array 302 to get the desired transmission/reflection/absorption pattern, optical detector array 308 having detectors D1-D4 is used. In this example, each memristor element MR1 . . . MR4 is comprised of a single memristor pixel and, therefore, detector array 308 includes a matching number of detectors. Also during calibration, as shown in
Referring to
Again, this phenomena occurs due to scattering and absorption effects caused by the metal ions diffused into semiconductor layer 16. By using the hysteresis curve (e.g.,
Each memristor element MR1 . . . MR4 is arranged in an order the desired application requires. For example, this particular example has 4 memristor pixels MR1 . . . MR4. However this can be extended to an ‘n×n’ pixel array. Moreover, the number of pixels in the horizontal and vertical direction can change with the application.
When memristor element array 302 is utilized in a desired application, each memristor element MR1 . . . MR4 may be communicably coupled to its own electromagnetic field producing element via leads 316 or wireless means. In certain illustrative embodiments, each electromagnetic field producing element (coupled to processing circuitry 314) may be programmed to produce electromagnetic fields having differing power levels, thereby providing the ability to alter the semiconductor layer 16 of each memristor element as desired. As a result, each memristor element MR1 . . . MR4 may have a different spectral property.
In this example, a voltage source is used as the electromagnetic field producing element. As broadband electromagnetic radiation 410 passes through each memristor element MR1 . . . MR4 in sequential fashion, radiation 410 optically interacts with each to produce optically-interacted light 412. Thus, when a varied voltage is applied across each memristor element MR1 . . . MR4, the ions from metal layer 18 enters defect ridden semiconductor layer 16, effectively decreasing and/or increasing the refractive index of defect ridden semiconductor layers 16. This creates a scenario of a high index material followed by low index material, which is similar to a traditional thin-film design. The number of ions diffusing into defect ridden semiconductor layer 16 is governed by the hysteresis voltage-current curve for the memristor element, as previously described. Moreover, just as in previous embodiments, each memristor element MR1 . . . MR4 may be communicably coupled to an electromagnetic field producing element to thereby alter the spectrally alterable material of layer 16.
Memristor element 505 is communicably coupled to an electromagnetic field producing element 504 via a wire leads 502. Although shown as a single electromagnetic field producing element, it may be comprised of multiple electromagnetic field producing elements when memristor element 505 includes a plurality of pixels or is an array. In such embodiments, each memristor element in the array may have its own dedicated wire leads or other suitable coupling mechanism. Alternatively, electromagnetic field producing element 504 may be communicably coupled to memristor element 505 via wireless means. Electromagnetic field producing element 504 may be a variety of devices, such as, for example, a current source, voltage source, electromagnetic source, magnetic source, thermal source or an ionic source. For example, electromagnetic field producing element 504 may be an electromagnetic field source which generates an electromagnetic wave and emits it toward memristor element 505. The electromagnetic wave will in turn induce a current across memristor element 505 which will alter the spectral properties the defect ridden semiconductor layer, as described herein.
In certain embodiments, spectrally programmable optical device 500 includes a detector, such as, for example, an optical transducer. In other embodiments, however, spectrally programmable optical device 500 will not comprise a detector and, in such cases, a human eye may serve as the detector. Applications in which the human eye acts as the detector for memristor element 505 may be, for example, architectural windows, car windows, spacecraft windows, solar front cover, solar concentrator or other applications whereby the memristor element is applied as a thin-film coating. In some of these embodiments, of course, natural luminescence may serve as the source of the electromagnetic radiation.
The spectrally programmable optical devices described herein may be utilized in a variety of other applications. Such applications may include, for example, downhole well or completion applications. Other environments may include those as diverse as those associated with surface and undersea monitoring, satellite or drone surveillance, pipeline monitoring, or even sensors transiting a body cavity such as a digestive tract. Within those applications, the spectrally programmable optical devices are utilized to detect/monitor various sample compounds or characteristics, in real time, within the environment.
The aforementioned spectrally programmable optical devices are illustrative in nature, and may be subject to a variety of other optical configurations. Such optical configurations not only include the reflection, absorption or transmission methods described herein, but can also involve scattering (Raleigh & Raman, for example) as well as emission (fluorescence, X-ray excitation, etc., for example).
Although not shown, the spectrally programmable optical devices described herein may be coupled to a remote power supply, while in other embodiments on-board batteries may be utilized. The spectrally programmable optical devices may also comprise a signal processor, communications module and other circuitry necessary to achieve the objectives of the present disclosure. It will also be recognized that the software instructions necessary to carry out the objectives of the present invention may be stored within storage located on the spectrally programmable optical devices or loaded into that storage from a CD-ROM or other appropriate storage media via wired or wireless methods.
Moreover, the memristor elements utilized in certain embodiments of the present disclosure may not be semiconductor-based. For example, plastic-based memristor elements or grapheme-based elements may also be utilized.
Embodiments described herein further relate to any one or more of the following paragraphs:
Although various embodiments and methodologies have been shown and described, the disclosure is not limited to such embodiments and methodologies and will be understood to include all modifications and variations as would be apparent to one skilled in the art. Therefore, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2015/027331 | 4/23/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2016/171701 | 10/27/2016 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3801966 | Terao | Apr 1974 | A |
7580596 | Meijer et al. | Aug 2009 | B1 |
7596016 | Johnson | Sep 2009 | B2 |
7768815 | Chen et al. | Aug 2010 | B2 |
8081129 | Santori | Dec 2011 | B1 |
8280054 | Bratkovski | Oct 2012 | B2 |
8395191 | Or-Bach et al. | Mar 2013 | B2 |
8440542 | Sekar et al. | May 2013 | B2 |
8477408 | Li | Jul 2013 | B2 |
8542518 | Bratkovski et al. | Sep 2013 | B2 |
8546785 | Yang et al. | Oct 2013 | B2 |
8557632 | Or-Bach et al. | Oct 2013 | B1 |
8575585 | Yang et al. | Nov 2013 | B2 |
8605483 | Williams et al. | Dec 2013 | B2 |
8609459 | Wen et al. | Dec 2013 | B2 |
8614432 | Pickett et al. | Dec 2013 | B2 |
8735863 | Fowler et al. | May 2014 | B2 |
8773167 | Robinett et al. | Jul 2014 | B2 |
9847129 | Buchanan | Dec 2017 | B2 |
20050221473 | Dubin et al. | Oct 2005 | A1 |
20100253997 | Li | Oct 2010 | A1 |
20100278474 | Beausoleil et al. | Nov 2010 | A1 |
20120012809 | Yang et al. | Jan 2012 | A1 |
20120154880 | Wu et al. | Jun 2012 | A1 |
20120281980 | Cho et al. | Nov 2012 | A1 |
20130095580 | Or-Bach et al. | Apr 2013 | A1 |
20130235651 | Perner et al. | Sep 2013 | A1 |
20140027702 | Lu et al. | Jan 2014 | A1 |
20140291602 | Kenyon et al. | Oct 2014 | A1 |
Number | Date | Country |
---|---|---|
10-2013-0065093 | Jun 2013 | KR |
WO 2011028208 | Mar 2011 | WO |
Entry |
---|
International Search Report and the Written Opinion of the International Search Authority, or the Declaration, dated Jan. 21, 2016, PCT/US2015/027331, 14 pages, ISA/KR. |
Kavehei et al., “The Fourth Element: Characteristics, Modelling and Electromagnetic Theory of the Memristor,” Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, p. rspa20090553. The Royal Society, Mar. 17, 2010. |
Strukov et al., “Hybrid CMOS/Memristor Circuits,” Circuits and Systems (ISCAS), Proceedings of 2010 IEEE International Symposium, pp. 1967-1970, May 30, 2010. |
Number | Date | Country | |
---|---|---|---|
20180113330 A1 | Apr 2018 | US |