Modern Optics

Optics is about light: how it is produced, propagated and detected. It is an interdisciplinary endeavor with roots in physics, electrical engineering, chemistry and materials science. From contact lenses to fiber optic communications, optics is used in every aspect of our lives. Optical research has led scientists to groundbreaking inventions such as lasers and holograms.

Modern optics covers the fields of optical science and engineering that were popular in the 20th century. These fields of optical science are generally related to the electromagnetic or quantum properties of light, but do include other topics. 

- Major Subfields of Modern Optics

A major subfield of modern optics, quantum optics, deals exclusively with the quantum mechanical properties of light. Quantum optics is not just theoretical; some modern devices, such as lasers, have working principles that rely on quantum mechanics. Light detectors, such as photomultiplier tubes and channel accelerators, respond to individual photons. Electronic image sensors, such as CCDs, exhibit shot noise that corresponds to the statistics of single photon events. Light-emitting diodes and photovoltaic cells cannot be understood without quantum mechanics. In the study of these devices, quantum optics often overlaps with quantum electronics.

Today, pure optical science is called optical science or optical physics to distinguish it from applied optical science, which is called optical engineering. Prominent subfields of optical engineering include lighting engineering, photonics, and optoelectronics, with practical applications such as lens design, fabrication and testing of optical components, and image processing. Some of these fields overlap, and the lines between subject terms are blurred, with slightly different meanings in different parts of the world and across different industry sectors. Due to advances in laser technology, a dedicated community of nonlinear optics researchers has developed over the past few decades.

Optical fibers, or fiber optic cables are carefully drawn long, thin strands of glass about the diameter of a human hair. These wires are arranged in bundles and are called fiber optic cables. We rely on them to transmit light signals over long distances. 

At the source, the light signal is encoded with data...the same data you see on your computer screen. So, fiber optics carry "data" through light to the receiving end, where the light signal is decoded into data. So fiber optics are actually a transmission medium -- a "pipe" that carries signals over long distances at very high speeds.

Fiber optic cables were originally developed in the 1950s for use in endoscopes. The goal is to help doctors see inside human patients without major surgery. In the 1960s, telephone engineers figured out a way to transmit and receive calls at the "speed of light" using the same technology. That's about 186,000 miles per second in a vacuum, but slows down to about two-thirds that speed in a cable. So, what is fiber used for? In short, for signal transmission, communication and vision.

Light propagates along the cable by repeated reflections from the cable walls. Each particle of light (photon) is reflected along the tube and continues to undergo internal specular reflections. 

The light beam propagates along the core wire of the cable. The core is in the middle of the cable and glass structure. Cladding is another layer of glass that wraps around the core. The role of the cladding is to keep the optical signal within the core.

- Research Areas in Optics

Specialized areas of optics research include studying how light interacts with specific materials, such as crystal optics and metamaterials. Other research focuses on the phenomenology of electromagnetic waves, such as singular optics, non-imaging optics, nonlinear optics, statistical optics, and radiometry. Additionally, computer engineers are interested in integrating optics, machine vision, and photonic computing as possible components of "next-generation" computers.

Optics allows for a wide range of modern research topics. Some of the research topics are listed below, including:

• Optical and quantum information processing
• Subwavelength optics (nano-optics)
• Subpicosecond lasers and phenomena
• Nonlinear optical materials
• Gradient index optics
• Quantum nature of absorption and emission of light
• Light propagation in microstructures
• Quantum imaging
• Slow and fast light propagation
• Theory, design, and fabrication of lasers
• Optimization of computer based optical system design
• Hybrid electrical-optical computing
• Remote sensing
• Physics of super-intense fields
• Diffractive optics
• Medical optics
• Fabrication of quantum-well devices
• Nonlinear dynamics and chaos
• Laser-driven fusion

[More to come ...]