Patents by Inventor Rajesh D. Rajavel
Rajesh D. Rajavel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11397282Abstract: Infrared-transparent and damage-resistant polymer optics with LWIR and/or MWIR transparency are provided. Some variations provide an optic containing at least 50 wt % of an infrared-transparent polymer, wherein the infrared-transparent polymer has a carbon-free polymer backbone, wherein the optic is characterized by at least 80% average transmission of radiation over a wavenumber band with cumulative wavenumber width of at least 1000 cm?1 contained within wavelengths from 3.1 ?m to 5 ?m and/or from 8.1 ?m to 12 ?m, and wherein the average transmission is defined as the percentage ratio of radiation intensity through an optic thickness of 25 microns divided by incident radiation intensity. Many polymer compositions and pendant groups are disclosed for use in the polymer optics.Type: GrantFiled: May 30, 2019Date of Patent: July 26, 2022Assignee: HRL Laboratories, LLCInventors: Adam F. Gross, Ashley M. Dustin, Andrew P. Nowak, April R. Rodriguez, Rajesh D. Rajavel, Jacob M. Hundley
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Patent number: 11302739Abstract: An infrared detector. The detector includes: a superlattice structure including: at least three first layers; and at least three second layers, alternating with the first layers. Each of the first layers includes, as a major component, InAsxP1-x, wherein x is between 0.0% and 99.0%, and each of the second layers includes, as a major component, InAsySb1-y, wherein y is between 0% and 60%.Type: GrantFiled: August 2, 2016Date of Patent: April 12, 2022Assignee: HRL Laboratories, LLCInventors: Minh B. Nguyen, Rajesh D. Rajavel, David H. Chow
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Patent number: 11282970Abstract: An apparatus and method for a detector are disclosed. The apparatus disclosed contains a non-absorbing layer shaped as one or more pyramids, one or more collector regions, an absorber layer disposed between the one or more collector regions and the non-absorbing layer, a first electrical contact, and a second electrical contact, wherein the absorber layer is configured to absorb photons of incident light and generate minority electrical carriers and majority electrical carriers, wherein the one or more collector regions are electrically connected with the absorber layer and with the first electrical contact for extracting the minority electrical carriers, and the absorber layer is electrically connected with the one or more collector regions and with the second electrical contact to extract the majority electrical carriers.Type: GrantFiled: February 13, 2012Date of Patent: March 22, 2022Assignee: HRL Laboratories, LLCInventors: Daniel Yap, Rajesh D. Rajavel, Sarabjit Mehta
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Patent number: 11264526Abstract: A phototransistor includes an emitter, a collector, and a base between the emitter and the collector. The base has a thickness greater than 500 nanometers and the base absorbs photons passing through the collector to the base.Type: GrantFiled: January 24, 2020Date of Patent: March 1, 2022Assignee: HRL Laboratories, LLCInventors: Minh B. Nguyen, Diego Carrasco, Rajesh D. Rajavel
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Patent number: 11251209Abstract: An infrared photo-detector array and a method for manufacturing it are disclosed. The infrared photo-detector array contains a plurality of pyramid-shaped structures, a first light-absorbing material supporting the plurality of the pyramid-shaped structure, a carrier-selective electronic barrier supporting the first light-absorbing material, a second light-absorbing material supporting the carrier-selective electronic barrier, and a metal reflector supporting the second light-absorbing material, wherein the plurality of the pyramid shaped structures are disposed on the side of the photo-detector array facing the incident light to be detected and the metal reflector is disposed on the opposite side of the photo-detector array. The method disclosed teaches how to manufacture the infrared photo-detector array.Type: GrantFiled: March 14, 2014Date of Patent: February 15, 2022Assignee: HRL Laboratories, LLCInventors: Daniel Yap, Rajesh D. Rajavel, Sarabjit Mehta, Terence J. De Lyon, Hasan Sharifi, Pierre-Yves Delaunay
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Patent number: 11063163Abstract: An infrared detector and a method for manufacturing it are disclosed. The infrared photo-detector contains a photo absorber layer responsive to infrared light, a first barrier layer disposed on the absorber layer, wherein the first barrier layer substantially comprises AlSb, a second barrier layer disposed on the first barrier layer, wherein the second barrier layer substantially comprises AlxGa1-xSb and a contact layer disposed on the second barrier layer.Type: GrantFiled: March 14, 2014Date of Patent: July 13, 2021Assignee: HRL Laboratories, LLCInventors: Terence J. De Lyon, Rajesh D. Rajavel
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Patent number: 10903261Abstract: An infrared photo-detector and a method for manufacturing it are disclosed. The infrared photo-detector contains a collector region, a first absorber layer absorbing a first wavelength band of incident light, wherein the first absorber layer is disposed between the collector region and the incident light, a second absorber layer absorbing a second wavelength band of light, wherein the first absorber layer is disposed between the second absorber layer and the incident light, at least one first electrical contact coupled with the first absorber layer, at least one second electrical contact coupled with the second absorber layer and at least one third electrical contact coupled with the collector, wherein the at least one third electrical contact provides a current associated with absorbed light of the first wavelength band and absorbed light of the second wavelength band. The method disclosed teaches how to manufacture the infrared photo-detector.Type: GrantFiled: March 14, 2014Date of Patent: January 26, 2021Assignee: HRL Laboratories, LLCInventors: Daniel Yap, Rajesh D. Rajavel
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Patent number: 10720456Abstract: Methods of fabrication and monolithic integration of a polycrystalline infrared detector structure deposit Group III-V compound semiconductor materials at a low deposition temperature within a range of about 300° C. to about 400° C. directly on an amorphous template. The methods provide wafer-level fabrication of polycrystalline infrared detectors and monolithic integration with a readout integrated circuit wafer for focal plane arrays.Type: GrantFiled: July 23, 2019Date of Patent: July 21, 2020Assignee: HRL Laboratories, LLCInventors: Terence J. DeLyon, Rajesh D. Rajavel, Sevag Terterian, Minh B. Nguyen, Hasan Sharifi
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Patent number: 10424608Abstract: Methods of fabrication and monolithic integration of a polycrystalline infrared detector structure deposit Group III-V compound semiconductor materials at a low deposition temperature within a range of about 300° C. to about 400° C. directly on an amorphous template. The methods provide wafer-level fabrication of polycrystalline infrared detectors and monolithic integration with a readout integrated circuit wafer for focal plane arrays.Type: GrantFiled: January 31, 2018Date of Patent: September 24, 2019Assignee: HRL Laboratories, LLCInventors: Terence J. DeLyon, Rajesh D. Rajavel, Sevag Terterian, Minh B. Nguyen, Hasan Sharifi
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Patent number: 10361333Abstract: A detector. The detector includes a first collector, a first interface layer on the first collector, a first absorber on the first interface layer, a second interface layer on the first absorber, and a second collector on the second interface layer. The first absorber is configured to absorb photons to generate electron-hole pairs. The first interface layer may include a barrier configured to impede the flow of majority carriers from the first absorber to the first collector. The second barrier may include a barrier configured to impede the flow of majority carriers from the first absorber, or from a second absorber, to the second collector.Type: GrantFiled: August 11, 2016Date of Patent: July 23, 2019Assignee: HRL Laboratories, LLCInventors: Rajesh D. Rajavel, Hasan Sharifi, Terence J. DeLyon
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Patent number: 10269996Abstract: A position sensitive detector includes a substrate, an absorber layer on the substrate, a barrier layer on the absorber layer, a contact layer on the barrier layer, and a first contact and a second contact on the contact layer. The barrier layer prevents a flow of majority carriers from the absorber layer to the contact layer. The position sensitive detector is sensitive to a lateral position between the first contact and the second contact of incident light on the contact layer.Type: GrantFiled: July 28, 2016Date of Patent: April 23, 2019Assignee: HRL Laboratories, LLCInventors: Hasan Sharifi, Rajesh D. Rajavel, Terence J. De Lyon, Daniel Yap
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Patent number: 9748427Abstract: The invention describes a device which enables MWIR photodetectors to operate at zero bias and deliver low dark current performance. The performance is achieved by incorporating a p-n junction in the barrier. The device consists of a p-type contact layer, a p-n junction in the compound barrier (CB) with graded composition and/or doping profiles, and an n-type absorber (p-CB-n) device.Type: GrantFiled: October 31, 2013Date of Patent: August 29, 2017Assignee: HRL Laboratories, LLCInventors: Rajesh D Rajavel, Hasan Sharifi, Terence J De Lyon, Pierre-Yves Delaunay, Brett Z Nosho
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Patent number: 9709711Abstract: A wavelength-selective optical diffuser comprising a substrate of a first material having opposite first and second surfaces, wherein said first material is transparent to a first wavelength ?S and a second wavelength ?L, with ?L>4?S; at least a first surface of said substrate having a surface relief such that a beam of light having the first wavelength ?S is diffused, with a rms phase delay S>?/4, when traversing said substrate; and a beam of light having the second wavelength ?L is minimally diffused, with a rms phase delay S<?/4, when traversing said substrate.Type: GrantFiled: September 18, 2013Date of Patent: July 18, 2017Assignees: HRL Laboratories, LLC, The Boeing CompanyInventors: Daniel Yap, Hasan Sharifi, Don F. Weston, Rajesh D. Rajavel
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Patent number: 9520525Abstract: An infrared photo-detector with multiple discrete regions of a first absorber material. These regions may have geometric shapes with sloped sidewalls. The detector also may include a second absorber region comprising a second absorber material that absorbs light of a shorter wavelength than the light absorbed by the multiple discrete absorber regions of the first absorber material. The geometric shapes may extend only through the first absorber material. Alternatively, the geometric shapes may extend partially into the second absorber region. The detector has a metal reflector coupled to the multiple discrete absorber regions. The detector also has a substrate containing the discrete absorber regions and the second absorber region. The substrate can further include geometric shaped features etched into the substrate, with those features formed on the side of the substrate opposite the side containing the discrete absorber regions and the second absorber region.Type: GrantFiled: January 9, 2015Date of Patent: December 13, 2016Assignee: HRL Laboratories, LLCInventors: Daniel Yap, Rajesh D. Rajavel, Sarabjit Mehta, Hasan Sharifi
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Patent number: 9490292Abstract: An infrared photo-detector array and a method for manufacturing it are disclosed. The infrared photo-detector array contains a collector layer, a first absorber layer that absorbs incident light of a first wavelength band and generates first electrons and first holes, a second absorber layer that absorbs incident light of a second wavelength band and generates second electrons and second holes, and wherein the wavelengths of the incident light in the first wavelength band are shorter than the wavelengths of the incident light in the second wavelength band, and wherein the second absorber layer is laterally contiguous across at least two photo-detectors. The method disclosed teaches how to manufacture the infrared photo-detector array.Type: GrantFiled: March 14, 2014Date of Patent: November 8, 2016Assignee: HRL Laboratories, LLCInventors: Daniel Yap, Rajesh D. Rajavel
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Patent number: 9466746Abstract: Using a multiple layer, varied composition barrier layer in place of the typical single layer barrier layer of an infrared photodetector results in a device with increased sensitivity and reduced dark current. A first barrier is adjacent the semiconductor contact; a second barrier layer is between the first barrier layer and the absorber layer. The barrier layers may be doped N type or P type with Beryllium, Carbon, Silicon or Tellurium. The energy bandgap is designed to facilitate minority carrier current flow in the contact region and block minority current flow outside the contact region.Type: GrantFiled: February 12, 2016Date of Patent: October 11, 2016Assignee: HRL Laboratories, LLCInventors: Terence J De Lyon, Rajesh D Rajavel, Hasan Sharifi
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Patent number: 9444001Abstract: A position sensitive detector includes a substrate, an absorber layer on the substrate, a barrier layer on the absorber layer, a contact layer on the barrier layer, and a first contact and a second contact on the contact layer. The barrier layer prevents a flow of majority carriers from the absorber layer to the contact layer. The position sensitive detector is sensitive to a lateral position between the first contact and the second contact of incident light on the contact layer.Type: GrantFiled: June 28, 2013Date of Patent: September 13, 2016Assignee: HRL Laboratories, LLCInventors: Hasan Sharifi, Rajesh D. Rajavel, Terence J. De Lyon, Daniel Yap
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Patent number: 9293612Abstract: Using a multiple layer, varied composition barrier layer in place of the typical single layer barrier layer of an infrared photodetector results in a device with increased sensitivity and reduced dark current. A first barrier is adjacent the semiconductor contact; a second barrier layer is between the first barrier layer and the absorber layer. The barrier layers may be doped N type or P type with Beryllium, Carbon, Silicon or Tellurium. The energy bandgap is designed to facilitate minority carrier current flow in the contact region and block minority current flow outside the contact region.Type: GrantFiled: August 7, 2014Date of Patent: March 22, 2016Assignee: HRL Laboratories, LLCInventors: Terence J De Lyon, Rajesh D Rajavel, Hasan Sharifi
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Patent number: 9231137Abstract: Using a highly doped Cap layer of the same composition as the Contact material in an nBn or pBp infrared photodetector allows engineering of the energy band diagram to facilitate minority carrier current flow in the contact region and block minority current flow outside the Contact region. The heavily doped Cap layer is disposed on the Barrier between the Contacts but electrically isolated from the Contact material.Type: GrantFiled: June 3, 2011Date of Patent: January 5, 2016Assignee: HRL Laboratories, LLCInventors: Hasan Sharifi, Terence J. De Lyon, Rajesh D. Rajavel
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Patent number: 9207120Abstract: A dual-band infrared detector is provided. The dual-band infrared detector includes a first absorption layer, a barrier layer coupled to the first absorption layer, and a second absorption layer coupled to the barrier layer. The first absorption layer is sensitive to only a first infrared wavelength band and the second absorption layer is sensitive to only a second infrared wavelength band that is different from the first infrared wavelength band. The dual-band infrared detector is capable of detecting the first wavelength band and the second wavelength band by applying a first bias voltage of a first polarity to the first absorption layer and by applying a second bias voltage of a second polarity that is opposite the first polarity to the second absorption layer, wherein the first bias voltage and the second bias voltage each have a magnitude of less than about 500 mV.Type: GrantFiled: July 15, 2013Date of Patent: December 8, 2015Assignee: The Boeing CompanyInventors: Rajesh D. Rajavel, Terence J. deLyon