Focusing and sensing apparatus, methods, and systems

• US 20090296237A1
• Filed: 05/30/2008
• 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 8,493,669 B2
• Time in Patent Office: Days
• US Class Current: 359/724
• CPC Class Codes: G02B 27/40 Optical focusing aids

Abstract

Apparatus, methods, and systems provide focusing, focus-adjusting, and sensing. In some approaches the focus-adjusting includes providing an extended depth of focus greater than a nominal depth of focus. In some approaches the focus-adjusting includes focus-adjusting 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 focusing structure oriented to receive input electromagnetic energy and having a nominal depth of focus for output electromagnetic energy; and

a focus-adjusting structure disposed to receive the output electromagnetic energy and having electromagnetic parameters that provide an extended depth of focus for the output electromagnetic energy greater than the nominal depth of focus, the electromagnetic parameters including;

axial electromagnetic parameters; and

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

22. The electromagnetic apparatus of claim 1, wherein the focusing structure includes a refractive structure.

26. The electromagnetic apparatus of claim 1, wherein the focusing structure includes a reflective structure.

28. The electromagnetic apparatus of claim 1, wherein the focusing structure includes a diffractive structure.

30. The electromagnetic apparatus of claim 1, wherein the focusing structure includes at least a portion of an antenna.

34. The electromagnetic apparatus of claim 1, wherein the extended depth of focus corresponds to an actual focusing region.

35. The electromagnetic apparatus of claim 34, further comprising:

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

46. The electromagnetic apparatus of claim 34, wherein the actual focusing region is at least partially within the focus-adjusting structure.

49. The electromagnetic apparatus of claim 46, wherein the electromagnetic parameters define an index of refraction having an absolute value less than one within at least a portion of the actual focusing region.

50. The electromagnetic apparatus of claim 1, wherein the focusing structure defines an axial direction, and the axial electromagnetic parameters correspond to the axial direction.

51. The electromagnetic apparatus of claim 50, wherein the axial direction corresponds to an optical axis of the focusing structure.

55. The electromagnetic apparatus of claim 50, wherein the transverse electromagnetic parameters correspond to a transverse direction, the transverse direction being substantially perpendicular to the axial direction.

58. The electromagnetic apparatus of claim 1, wherein the axial electromagnetic parameters include an axial permittivity.

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

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

61. The electromagnetic apparatus of claim 60, wherein the transverse electromagnetic parameters include a transverse permeability that is substantially a multiplicative inverse of the axial permeability.

62. The electromagnetic apparatus of claim 60, 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.

64. The electromagnetic apparatus of claim 1, wherein the focusing structure and the focus-adjusting structure have a spatial separation.

65. The electromagnetic apparatus of claim 64, wherein the spatial separation defines an intermediate region between the focusing structure and the focus-adjusting structure, and wherein the focus-adjusting structure includes an input surface region that is substantially nonreflective of electromagnetic energy incident upon the input surface region from the intermediate region.

67. The electromagnetic apparatus of claim 65, wherein a wave impedance of the intermediate region is substantially equal to a wave impedance of the input surface region.

68. The electromagnetic apparatus of claim 67, wherein the intermediate 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.

73. The electromagnetic apparatus of claim 68, 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.

74. The electromagnetic apparatus of claim 73, 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.

75. The electromagnetic apparatus of claim 1, wherein the focusing structure and the focus-adjusting structure define a composite unit.

76. The electromagnetic apparatus of claim 75, wherein the focusing structure includes an output surface region and the focus-adjusting structure includes an input surface region substantially adjoining the output surface region, the input surface region being substantially nonreflective of electromagnetic energy incident upon the input surface region from the output surface region.

78. The electromagnetic apparatus of claim 76, wherein a wave impedance of the output surface region is substantially equal to a wave impedance of the input surface region.

79. The electromagnetic apparatus of claim 78, wherein the output surface 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.

80. The electromagnetic apparatus of claim 79, 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.

81. The electromagnetic apparatus of claim 80, 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.

82. The electromagnetic apparatus of claim 1, wherein the focus-adjusting structure includes an artificially-structured material having an effective electromagnetic response that corresponds to the electromagnetic parameters.

83. The electromagnetic apparatus of claim 82, wherein the artificially-structured material includes a photonic crystal.

87. The electromagnetic apparatus of claim 82, wherein the artificially-structured material includes a metamaterial.

88. The electromagnetic apparatus of claim 87, 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.

89. The electromagnetic apparatus of claim 88, wherein the distributed electromagnetic responses include distributed inductive responses.

90. The electromagnetic apparatus of claim 88, wherein the distributed electromagnetic responses include distributed capacitive responses.

91. The electromagnetic apparatus of claim 88, wherein the distributed electromagnetic responses include distributed inductive-capacitive responses.

92. The electromagnetic apparatus of claim 88, wherein the at least one electromagnetically-responsive structure includes transmission lines.

96. The electromagnetic apparatus of claim 87, 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.

104. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include discrete circuit elements.

105. The electromagnetic apparatus of claim 104, wherein the discrete circuit elements include inductors.

106. The electromagnetic apparatus of claim 104, wherein the discrete circuit elements include capacitors.

107. The electromagnetic apparatus of claim 104, wherein the discrete circuit elements include semiconductor devices.

108. The electromagnetic apparatus of claim 107, wherein the semiconductor devices include diodes.

109. The electromagnetic apparatus of claim 107, wherein the semiconductor devices include transistors.

110. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include integrated circuit elements.

111. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include printed circuit elements.

112. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include metallic structures.

113. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include LC resonators.

114. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include plasmonic resonators.

115. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include nanostructures.

116. The electromagnetic apparatus of claim 115, wherein the nanostructures include nanorods.

117. The electromagnetic apparatus of claim 116, wherein the nanorods are paired nanorods.

118. The electromagnetic apparatus of claim 116, wherein the nanorods are interconnected to compose a fishnet structure.

119. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include split-ring resonators.

120. The electromagnetic apparatus of claim 96, wherein the electromagnetically responsive elements include subwavelength elements having spatial extents substantially less than a free space wavelength corresponding to a frequency of the input electromagnetic energy.

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