Negatively-refractive focusing and sensing apparatus, methods, and systems

• US 20090296225A1
• Filed: 07/25/2008
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: The Invention Science Fund I, L.L.C. (Intellectual Ventures LLC)
• Original Assignee: Searete LLC (Intellectual Ventures LLC)
• Inventors: Weaver, Thomas A., Smith, David R., Pendry, John Brian, Tegreene, Clarence T., Jung, Edward K.Y., Whitmer, Charles, Wood, Lowell L. JR., Hyde, Roderick A., Schurig, David, Bowers, Jeffrey A.
• Granted Patent: US 9,019,632 B2
• Time in Patent Office: Days
• US Class Current: 359/642
• CPC Class Codes: G02B 27/40 Optical focusing aids

Abstract

Apparatus, methods, and systems provide negatively-refractive focusing and sensing of electromagnetic energy. In some approaches the negatively-refractive focusing includes providing an interior focusing region with an axial magnification substantially greater than one. In some approaches the negatively-refractive focusing includes negatively-refractive focusing with a transformation medium, where the transformation medium may include an artificially-structured material such as a metamaterial.

Claims

1. An electromagnetic apparatus, comprising:

a negatively-refractive focusing structure disposed to receive electromagnetic energy in an interior focusing region with an axial magnification substantially greater than one.

21. The electromagnetic apparatus of claim 1, further comprising:

at least one electromagnetic sensor positioned within the interior focusing region.

32. The electromagnetic apparatus of claim 1, wherein the negatively-refractive focusing structure is disposed to receive electromagnetic energy from an exterior field region.

33. The electromagnetic apparatus of claim 32, wherein the axial magnification corresponds to a ratio of an axial extent of the interior focusing region to an axial extent of the exterior field region.

41. The electromagnetic apparatus of claim 1, wherein the negatively-refractive focusing structure is characterized by electromagnetic parameters that include:

axial electromagnetic parameters; and

transverse electromagnetic parameters that inversely correspond to the axial electromagnetic parameters.

43. The electromagnetic apparatus of claim 41, wherein the electromagnetic parameters define a negative index of refraction within at least a portion of the interior focusing region.

45. The electromagnetic apparatus of claim 41, wherein the electromagnetic parameters define an index of refraction less than zero and greater than minus one within at least a portion of the interior focusing region.

46. The electromagnetic apparatus of claim 41, wherein the negatively-refractive focusing structure defines an axial direction, and the axial electromagnetic parameters correspond to the axial direction.

51. The electromagnetic apparatus of claim 46, wherein the transverse electromagnetic parameters correspond to a transverse direction, the transverse direction being substantially perpendicular to the axial direction.

54. The electromagnetic apparatus of claim 41, wherein the axial electromagnetic parameters include an axial permittivity.

55. The electromagnetic apparatus of claim 54, wherein the transverse electromagnetic parameters include a transverse permittivity that is substantially a multiplicative inverse of the axial permittivity.

57. The electromagnetic apparatus of claim 55, wherein the axial permittivity is less than minus one.

58. The electromagnetic apparatus of claim 54, wherein the axial electromagnetic parameters include an axial permeability.

59. The electromagnetic apparatus of claim 58, wherein the transverse electromagnetic parameters include a transverse permeability that is substantially a multiplicative inverse of the axial permeability.

61. The electromagnetic apparatus of claim 59, wherein the axial permeability is less than minus one.

62. The electromagnetic apparatus of claim 58, wherein the axial permittivity is substantially equal to the axial permeability.

63. The electromagnetic apparatus of claim 62, wherein the transverse electromagnetic parameters include a transverse permeability that is substantially a multiplicative inverse of the axial permeability.

65. The electromagnetic apparatus of claim 63, wherein the axial permeability is less than minus one.

66. The electromagnetic apparatus of claim 1, wherein the negatively-refractive focusing structure includes an input surface region that is substantially nonreflective of electromagnetic energy incident upon the input surface region.

67. The electromagnetic apparatus of claim 66, wherein the input surface region is substantially nonreflective of electromagnetic energy incident upon the input surface region from an adjacent region, the adjacent region being exterior to the negatively-refractive focusing structure.

69. The electromagnetic apparatus of claim 67, wherein a wave impedance of the adjacent region is substantially equal to a wave impedance of the input surface region.

70. The electromagnetic apparatus of claim 69, wherein the adjacent region defines a first permittivity and a first permeability, the input surface region defines a second permittivity and a second permeability, and a ratio of the second permittivity to the first permittivity is substantially equal to a ratio of the second permeability to the first permeability.

75. The electromagnetic apparatus of claim 70, wherein the second permittivity is less than zero.

76. The electromagnetic apparatus of claim 70, wherein the second permeability is less than zero.

77. The electromagnetic apparatus of claim 76, wherein the second permittivity is less than zero.

78. The electromagnetic apparatus of claim 70, wherein the input surface region defines a surface normal direction and a surface parallel direction, the second permittivity includes a surface normal permittivity corresponding to the surface normal direction and a surface parallel permittivity corresponding to the surface parallel direction, and a ratio of the surface normal permittivity to the first permittivity is substantially a multiplicative inverse of a ratio of the surface parallel permittivity to the first permittivity.

80. The electromagnetic apparatus of claim 78, wherein the ratio of the surface normal permittivity to the first permittivity is less than minus one.

81. The electromagnetic apparatus of claim 78, wherein the second permeability includes a surface normal permeability corresponding to the surface normal direction and a surface parallel permeability corresponding to the surface parallel direction, and a ratio of the surface normal permeability to the first permeability is substantially a multiplicative inverse of a ratio of the surface parallel permeability to the first permeability.

83. The electromagnetic apparatus of claim 81, wherein the ratio of the surface normal permittivity to the first permittivity is less than minus one.

84. The electromagnetic apparatus of claim 1, wherein the negatively-refractive focusing structure includes an artificially-structured material having an effective electromagnetic response that corresponds to the electromagnetic parameters.

85. The electromagnetic apparatus of claim 84, wherein the interior focusing region is at least partially inside the artificially-structured material.

86. The electromagnetic apparatus of claim 85, wherein the interior focusing region is completely inside the artificially-structured material.

87. The electromagnetic apparatus of claim 84, wherein the artificially-structured material includes a photonic crystal.

91. The electromagnetic apparatus of claim 84, wherein the artificially-structured material includes a metamaterial.

92. The electromagnetic apparatus of claim 91, wherein the metamaterial includes at least one electromagnetically-responsive structure having a plurality of distributed electromagnetic responses, the plurality of distributed electromagnetic responses composing the effective electromagnetic response.

93. The electromagnetic apparatus of claim 92, wherein the distributed electromagnetic responses include distributed inductive responses.

94. The electromagnetic apparatus of claim 92, wherein the distributed electromagnetic responses include distributed capacitive responses.

95. The electromagnetic apparatus of claim 92, wherein the distributed electromagnetic responses include distributed inductive-capacitive responses.

96. The electromagnetic apparatus of claim 92, wherein the at least one electromagnetically-responsive structure includes transmission lines.

100. The electromagnetic apparatus of claim 91, wherein the metamaterial includes a plurality of electromagnetically responsive elements disposed at a plurality of spatial locations and having a plurality of individual responses, the plurality of individual responses composing the effective electromagnetic response.

108. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include discrete circuit elements.

109. The electromagnetic apparatus of claim 108, wherein the discrete circuit elements include inductors.

110. The electromagnetic apparatus of claim 108, wherein the discrete circuit elements include capacitors.

111. The electromagnetic apparatus of claim 108, wherein the discrete circuit elements include semiconductor devices.

112. The electromagnetic apparatus of claim 111, wherein the semiconductor devices include diodes.

113. The electromagnetic apparatus of claim 111, wherein the semiconductor devices include transistors.

114. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include integrated circuit elements.

115. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include printed circuit elements.

116. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include metallic structures.

117. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include LC resonators.

118. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include plasmonic resonators.

119. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include nanostructures.

120. The electromagnetic apparatus of claim 119, wherein the nanostructures include nanorods.

121. The electromagnetic apparatus of claim 120, wherein the nanorods are paired nanorods.

122. The electromagnetic apparatus of claim 120, wherein the nanorods are interconnected to compose a fishnet structure.

123. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include split-ring resonators.

124. The electromagnetic apparatus of claim 100, wherein the electromagnetically responsive elements include subwavelength elements having spatial extents substantially less than a free space wavelength corresponding to a frequency of the electromagnetic energy.

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