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Electromagnetic Fields in Complex Mediums. Akhlesh Lakhtakia Department of Engineering Science and Mechanics The Pennsylvania State University. February 27, 2006 Department of Electronics Engineering Institute of Technology, BHU Varanasi, India. What is a Medium ?.
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Electromagnetic Fields in Complex Mediums Akhlesh Lakhtakia Department of Engineering Science and Mechanics The Pennsylvania State University February 27, 2006 Department of Electronics Engineering Institute of Technology, BHU Varanasi, India
What is a Medium? A spacetime manifold allowing signals to propagate Free Space (Reference Medium) Vacuum (Gravitation? Quantum?) Materials
What is Complex? That which is not SIMPLE! What is SIMPLE? Textbook stuff!
From the Microscopic to the Macroscopic Microscopic Fields: Discrete (point) Charges:
From the Microscopic to the Macroscopic Maxwell Postulates (microscopic): Nonhomogeneous Nonhomogeneous Homogeneous Homogeneous
From the Microscopic to the Macroscopic Maxwell Postulates (macroscopic): spatial averaging Nonhomogeneous Nonhomogeneous Homogeneous Homogeneous
From the Microscopic to the Macroscopic Free sources (impressed) Bound sources (matter)
From the Microscopic to the Macroscopic Induction fields:
From the Microscopic to the Macroscopic Maxwell Postulates (macroscopic): Nonhomogeneous Nonhomogeneous Homogeneous Homogeneous Free sources Bound sources (induction fields)
From the Microscopic to the Macroscopic Maxwell Postulates (macroscopic): Nonhomogeneous Nonhomogeneous Homogeneous Homogeneous
Constitutive Relations(always macroscopic) Primitive fields: Induction fields: D and H as functions of E and B
Constitutive Relations(always macroscopic) D and H as functions of E and B Simplest medium: Free space Simple medium: Linear, Homogeneous, Isotropic, Dielectric Delay Absorption Complex medium: Everything else Delay Absorption Anisotropy Chirality Nonhomogeneity Nonlinearity
Macroscopic Maxwell Postulates (Time-Harmonic) Temporal Fourier Transformation:
Constitutive Relations(always macroscopic) Free space Linear, isotropic dielectric
Constitutive Relations(always macroscopic) 3. Linear, anisotropic dielectric
Constitutive Relations(always macroscopic) 4. Linear bianisotropic:
Constitutive Relations(always macroscopic) 4. Linear bianisotropic: Structural constraint (Post): Reciprocity: Crystallographic symmetries: ….
Constitutive Relations(always macroscopic) 5. Nonlinear bianisotropic:
Constitutive Relations(always macroscopic) 5. Nonlinear bianisotropic:
There is no end to Complexity. Lifetime Job Security!
My CME Research(2001-2005) • Sculptured Thin Films • Homogenization of Composite Materials • Negative-Phase-Velocity Propagation • Related Topics in Nanotechnology • Carbon nanotubes • Broadband ultraviolet lithography • Photonic bandgap structures • Fundamental CME Issues
Sculptured Thin Films Conceived by Lakhtakia & Messier (1992-1995) Nanoengineered Materials (1-3 nm clusters) Assemblies of Parallel Curved Nanowires/Submicronwires Controllable Nanowire Shape 2-D - nematic 3-D - helicoidal combination morphologies vertical sectioning Controllable Porosity (10-90 %)
Physical Vapor Deposition (Columnar Thin Films)
Physical Vapor Deposition (Sculptured Thin Films) Rotate about y axis for nematic morphology Rotate about z axis for helicoidal morphology Mix and match rotations for complex morphologies
Sculptured Thin Films Optical Devices: Polarization Filters Bragg Filters Ultranarrowband Filters Fluid Concentration Sensors Bacterial Sensors Biomedical Applications: Tissue Scaffolds Drug/Gene Delivery Bone Repair Virus Traps Other Applications
Optical Modeling of STFs Homogenize a collection of parallel ellipsoids to get
STFs with Transverse Architecture 1.5 um x 1.5 um photoresist pattern fabricated using a lithographic stepper Chiral SiO2 thin films grown using e-beam evaporation 2 KX 17 KX Different periods achieved by changing deposition conditions 100 KX 40 KX
Metamaterials Rodger Walser
Homogenization of Composite Materials Particulate Composite Material with ellipsoidal inclusions