# US 2013/0153765 A1 · Photoconductive antenna, terahertz wave generating device, camera, imaging device, and measuring device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153765 A1 - Document ID: US20130153765A1 - Status: Published application - Kind: A1 - Application number: 13/717,835 - Filed: 2012-12-18 - Published: 2013-06-20 - Earliest claimed: 2011-12-20 - Assignees: Seiko Epson Corporation - Inventors: Hiroto TOMIOKA - Web page: https://patentgrep.com/patent/US20130153765A1 ## CPC - H10H 20/00: Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED] - G01S 17/89: for mapping or imaging - H10F 30/10: the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors - H10F 39/107: {having multiple elements covered by H10F30/00 in a repetitive configuration, e.g. radiation detectors comprising photodiode arrays} - H10F 39/802: {Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes} - H10F 39/806: {Optical elements or arrangements associated with the image sensors} - H10F 55/20: wherein the electric light source controls the radiation-sensitive semiconductor devices, e.g. optocouplers - G01N 21/3581: using far infrared light; using Terahertz radiation - G01S 13/89: for mapping or imaging - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A photoconductive antenna is adapted to generate terahertz waves when irradiated by pulsed light. The photoconductive antenna includes first and second conductive layers, a semiconductor layer positioned between the first and second conductive layers, first and second electrodes, and a dielectric layer. The semiconductor layer is made of a semiconductor material having a carrier density that is lower than a carrier density of the semiconductor material of the first conductive layer or the second conducive layer. The first and second electrodes are electrically connected to the first and second conductive layers, respectively. The second electrode has an aperture through which the pulsed light passes. The dielectric layer is made of a dielectric material, and is in contact with a surface of the semiconductor layer having a normal direction extending orthogonal to a lamination direction of the first conductive layer, the semiconductor layer, and the second conductive layer. ## Claims ### Claim 1 A photoconductive antenna adapted to generate terahertz waves when irradiated by pulsed light, the photoconductive antenna comprising: a first conductive layer made of a semiconductor material containing a first conductive type impurity; a second conductive layer made of a semiconductor material containing a second conductive type impurity different from the first conductive type impurity; a semiconductor layer positioned between the first conductive layer and the second conductive layer, and made of a semiconductor material having a carrier density that is lower than a carrier density of the semiconductor material of the first conductive layer or a carrier density of the semiconductor material of the second conducive layer; a first electrode electrically connected to the first conductive layer; a second electrode electrically connected to the second conductive layer, and having an aperture through which the pulsed light passes; and a dielectric layer made of a dielectric material, and being in contact with a surface of the semiconductor layer having a normal direction extending orthogonal to a lamination direction of the first conductive layer, the semiconductor layer, and the second conductive layer. ### Claim 2 (depends on 1) The photoconductive antenna according to claim 1, wherein a relative dielectric constant of the dielectric material is higher than a relative dielectric constant of the semiconductor material of the semiconductor layer. ### Claim 3 (depends on 1) The photoconductive antenna according to claim 1, wherein a width of a part of the dielectric layer as viewed along the lamination direction increases as a distance from the semiconductor layer increases. ### Claim 4 (depends on 1) The photoconductive antenna according to claim 1, further comprising a covering layer covering a part of the surface of the semiconductor layer which is not in contact with the dielectric layer. ### Claim 5 (depends on 1) The photoconductive antenna according to claim 1, further comprising a first reflective layer in contact with a bottom surface of the dielectric layer, and configured and arranged to reflect the terahertz waves. ### Claim 6 (depends on 1) The photoconductive antenna according to claim 1, wherein the first electrode is configured and arranged to reflect the terahertz waves. ### Claim 7 (depends on 1) The photoconductive antenna according to claim 1, further comprising a second reflective layer in contact with a top surface of the dielectric layer, and configured and arranged to reflect the terahertz waves. ### Claim 8 (depends on 1) The photoconductive antenna according to claim 1, wherein the second electrode is configured and arranged to reflect the terahertz waves. ### Claim 9 (depends on 1) The photoconductive antenna according to claim 1, wherein the second conductive layer includes a thin walled part having a thickness in the lamination direction that is thinner than a part of the second conductive layer disposed outside of the aperture as viewed along the lamination direction. ### Claim 10 (depends on 1) The photoconductive antenna according to claim 1, wherein the semiconductor material of the semiconductor layer is a III-V compound. ### Claim 11 (depends on 1) A terahertz wave generating device comprising: the photoconductive antenna according to claim 1; and a light source configured and arranged to generate the pulsed light. ### Claim 12 (depends on 2) A terahertz wave generating device comprising: the photoconductive antenna according to claim 2; and a light source configured and arranged to generate the pulsed light. ### Claim 13 (depends on 1) A camera comprising: the photoconductive antenna according to claim 1; a light source configured and arranged to generate the pulsed light; and a terahertz wave detecting unit configured and arranged to detect the terahertz waves emitted from the photoconductive antenna and reflected by an object. ### Claim 14 (depends on 2) A camera comprising: the photoconductive antenna according to claim 2; a light source configured and arranged to generate the pulsed light; and a terahertz wave detecting unit configured and arranged to detect the terahertz waves emitted from the photoconductive antenna and reflected by an object. ### Claim 15 (depends on 1) An imaging device comprising: the photoconductive antenna according to claim 1; a light source configured and arranged to generate the pulsed light; a terahertz wave detecting unit configured and arranged to detect the terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and an image forming unit configured and arranged to generate an image of the object based on detection results of the terahertz wave detecting unit. ### Claim 16 (depends on 15) The imaging device according to claim 15, wherein the image forming unit is configured and arranged to generate the image of the object using intensity of the terahertz waves detected by the terahertz wave detecting unit. ### Claim 17 (depends on 2) An imaging device comprising: the photoconductive antenna according to claim 2; a light source configured and arranged to generate the pulsed light; a terahertz wave detecting unit configured and arranged to detect the terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and an image forming unit configured and arranged to generate an image of the object based on detection results of the terahertz wave detecting unit. ### Claim 18 (depends on 17) The imaging device according to claim 17, wherein the image forming unit is configured and arranged to generate the image of the object using intensity of the terahertz waves detected by the terahertz wave detecting unit. ### Claim 19 (depends on 1) A measuring device comprising: the photoconductive antenna according to claim 1; a light source configured and arranged to generate the pulsed light; a terahertz wave detecting unit configured and arranged to detect the terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and a measuring unit configured and arranged to measure the object based on detection results of the terahertz wave detecting unit. ### Claim 20 (depends on 19) The measuring device according to claim 19, wherein the measuring unit is configured and arranged to measure the object using intensity of the terahertz waves detected by the terahertz wave detecting unit. ### Claim 21 (depends on 2) A measuring device comprising: the photoconductive antenna according to claim 2; a light source configured and arranged to generate the pulsed light; a terahertz wave detecting unit configured and arranged to detect the terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and a measuring unit configured and arranged to measure the object based on detection results of the terahertz wave detecting unit. ### Claim 22 (depends on 21) The measuring device according to claim 21, wherein the measuring unit is configured and arranged to measure the object using intensity of the terahertz waves detected by the terahertz wave detecting unit.