1 List of Abbreviations
2 Introduction
 2.1 Graphene-Based Structures
  2.1.1 Electronic Properties
  2.1.2 Optical Properties
 2.2 Quantum Cascade Structures
  2.2.1 Three-Well Vertical Design
  2.2.2 Superlattice Design
  2.2.3 Diagonal Transition Design
  2.2.4 Short Pulse Generation
 2.3 Outline of This Work
3 Optical Properties of Armchair Graphene Nanoribbons
 3.1 Models
  3.1.1 First Principle Calculations
  3.1.2 Tight-Binding Model
  3.1.3 Non-Equilibrium Green’s Function
 3.2 Optical Matrix Elements
 3.3 Dielectric Response
 3.4 Conclusions
4 Optical Properties of Zigzag Graphene Nanoribbons
 4.1 Electronic Band Structure
 4.2 Wave Functions
 4.3 Optical Matrix Elements
 4.4 Results and Discussion
 4.5 Conclusions
5 Graphene Superlattice-Based Photodetectors
 5.1 Graphene Superlattice Properties
 5.2 Line-edge Roughness Effects
 5.3 Conclusions
6 Quantum Cascade Lasers
 6.1 Models
  6.1.1 Pauli-Master Equation
  6.1.2 Particle Swarm Optimization
 6.2 Performance Optimization
  6.2.1 Optimization of a Three-Well Vertical Design
  6.2.2 Optimization of a Superlattice Design
  6.2.3 Optimization of a THz Design
 6.3 Dynamics of QCLs
 6.4 Quantum Cascade Detectors
7 Summary and Conclusions
A AGNR Optical Matrix Elements
B ZGNR Optical Matrix Elements
 B.1 Bloch Wave Functions Prefactors
 B.2 Transverse Wave Functions Amplitude
 B.3 Optical Matrix Elements
C QCL Linear Stability Analysis