SiO2/TiO2 distributed Bragg reflector near 1.5 μm fabricated by e-beam evaporation
The authors report on the fabrication and characterization of SiO2/TiO2 distributed Bragg reflector (DBR) mirrors operating at the eye safe and optical communication wavelength window, λ = 1.5 μm. Our experimental results demonstrated that SiO2/TiO2 DBR mirrors with reflectivity exceeding 95% at λ = 1.5 μm can be achieved using e-beam evaporation in conjunction with postdeposition thermal annealing process in ambient air. It was found that the postdeposition annealing process transformed the crystal structure of the as-deposited TixOy to TiO2, leading to a significant reduction in optical absorption. Erbium doped III-nitride semiconductors incorporating DBR mirrors at 1.5 μm emission may open up many novel applications, including infrared emitters, optical amplifiers, and high power infrared lasers.
Fabrication and analysis of highly-reflective metal-dielectric mirrors for high-performance semiconductor laser applications
Abstract The device performance improvement of ridge waveguide (RWG) laser diodes (LDs), operating at a wavelength (λ) of ∼960 nm, with a metal-dielectric high-reflection (HR) mirror consisting of Au/Ti–SiO 2 layers on the back facet was demonstrated. To determine the optimum thickness of each layer, optical reflection calculations were performed using a rigorous coupled-wave analysis method, which leads to the resultant Au (80 nm)/Ti (5 nm)–SiO 2 (164 nm) layers. The layers exhibited a broad high reflection band of >91% over a wavelength range of 920–1000 nm, indicating the reflectivity of ∼91.2% at λ ∼ 960 nm. For 2 mm-cavity RWG LDs with the Au/Ti–SiO 2 HR mirror, an enhanced maximum output power (P max ) of 499.3 mW at an injection current of 3000 mA and a decreased threshold current (I th ) of 516 mA (i.e., P max  = 259.4 mW and I th  = 650 mA for the uncoated LDs) were obtained, showing an increased slope efficiency percentage of 82%. The external differential quantum efficiency was also increased from ∼17.1 to ∼31.1%. Also, the full widths at half maximum values of beam divergences of the device were 38° (vertical direction) and 4° (horizontal direction).
A Historical Introduction to the Law of Obligations
1 PROLOGUE: THE PREHISTORY OF THE ENGLISH LAW OF OBLIGATIONS 2 STRUCTURAL FOUNDATIONS 3 UNITY AND FRAGMENTATION OF THE MEDIAEVAL LAW OF CONTRACT 4 TRESPASS, TRESPASS ON THE CASE, AND THE MEDIAEVAL LAW OF TORT 5 THE SUBSTANTIVE LAW OF TORTS 6 THE SUBSTANTIVE LAW OF CONTRACT PART 2 THE TRIUMPH OF TRESPASS ON THE CASE 7 TORT, PROPERTY, AND REPUTATION: THE EXPANSION OF THE ACTION ON THE CASE 8 THE RISE OF THE ACTION OF ASSUMPSIT PART 3 THE MODERN LAW OF TORT AND CONTRACT 9 TRESPASS, CASE, AND THE MORAL BASIS OF LIABILITY 10 THE LAW OF TORTS IN THE NINETEENTH CENTURY: THE RISE OF THE TORT OF NEGLIGENCE 11 THE LAW OF TORTS IN THE TWENTIETH CENTURY: EXPANSION AND COLLAPSE OF THE TORT OF NEGLIGENCE 12 FOUNDATIONS OF THE MODERN LAW OF CONTRACT 13 THE RISE OF THE WILL THEORY THE WILL THEORY AND THE CLASSICAL MODEL OF CONTRACT 14 THE DECLINE OF THE WILL THEORY: LEGAL REGULATION AND CONTRACTUAL FAIRNESS PART 4 UNJUST ENRICHMENT 15 UNJUST ENRICHMENT 16 LEGAL CHANGE AND LEGAL CONTINUITY