Modern Photonics of Nano- and Microsystems

- Overview

Photonics is the technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. Photonics is the physical science of light (photon) generation, detection, and manipulation through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s.

Photonics involves cutting-edge uses of lasers, optics, fiber-optics, and electro-optical devices in numerous and diverse fields of technology – alternate energy, manufacturing, health care, telecommunication, environmental monitoring, homeland security, aerospace, solid state lighting, and many others.

- Modern Optics

Photonics is related to quantum optics, optomechanics, electro-optics, optoelectronics and quantum electronics. However, each area has slightly different connotations by scientific and government communities and in the marketplace. Quantum optics often connotes fundamental research, whereas photonics is used to connote applied research and development. 

The term photonics more specifically connotes:

• The particle properties of light,
• The potential of creating signal processing device technologies using photons,
• The practical application of optics, and
• An analogy to electronics.

The term optoelectronics connotes devices or circuits that comprise both electrical and optical functions, i.e., a thin-film semiconductor device. The term electro-optics came into earlier use and specifically encompasses nonlinear electrical-optical interactions applied, e.g., as bulk crystal modulators such as the Pockels cell, but also includes advanced imaging sensors.

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- Emerging Fields

Photonics also relates to the emerging science of quantum information and quantum optics. Other emerging fields include:

• Optoacoustics or photoacoustic imaging where laser energy delivered into biological tissues will be absorbed and converted into heat, leading to ultrasonic emission.
• Optomechanics, which involves the study of the interaction between light and mechanical vibrations of mesoscopic or macroscopic objects;
• Opto-atomics, in which devices integrate both photonic and atomic devices for applications such as precision timekeeping, navigation, and metrology;
• Polaritonics, which differs from photonics in that the fundamental information carrier is a polariton. Polaritons are a mixture of photons and phonons, and operate in the range of frequencies from 300 gigahertz to approximately 10 terahertz.
• Programmable photonics, which studies the development of photonic circuits that can be reprogrammed to implement different functions in the same fashion as an electronics FPGA

- Applications

Applications of photonics are ubiquitous. Included are all areas from everyday life to the most advanced science, e.g. light detection, telecommunications, information processing, photonic computing, lighting, metrology, spectroscopy, holography, medicine (surgery, vision correction, endoscopy, health monitoring), biophotonics, military technology, laser material processing, art diagnostics (involving InfraRed Reflectography, Xrays, UltraViolet fluorescence, XRF), agriculture, and robotics.  

Just as applications of electronics have expanded dramatically since the first transistor was invented in 1948, the unique applications of photonics continue to emerge. Economically important applications for semiconductor photonic devices include optical data recording, fiber optic telecommunications, laser printing (based on xerography), displays, and optical pumping of high-power lasers. The potential applications of photonics are virtually unlimited and include chemical synthesis, medical diagnostics, on-chip data communication, sensors, laser defense, and fusion energy, to name several interesting additional examples.

- Photonics-Enabled Fields

• Aerospace technology – Uses LiDAR (laser RADAR systems) and laser altimeters, imaging systems for test and analysis of aircraft, holographic heads-up displays, and optical pattern recognition systems for navigation
• Agriculture – Uses satellite remote sensing to detect large-scale crop effects, scanning technology and infrared imaging to monitor food production and quality, and sensor systems for planting and irrigation
• Biomedicine – Uses lasers for surgery, therapies such as photodynamic therapy, and in situ keratomileusis (LASIK) procedures; uses testing and analysis devices such as noninvasive glucose monitors
• Construction – Includes scanning site topography, laser bar-code readers to inventory materials, laser distance measuring and alignment, and three-dimensional analysis to track the progress of construction
• Engineering, microtechnology, and nanotechnology – Uses lasers in the manufacture of electrical devices, motors, engines, semiconductor chips, circuits, and computers; via photolithography, photonics is central to MEMS production
• Alternate Energy / Green Solutions – Photovoltaic Devices (PVDs) are used for Solar Electric Panels. Recent improvements in cost, efficiency, and reliability promise that PVDs will be an even greater contributor to Alternative Electric Energy in the future.
• Environmental technology – Uses ultraviolet Doppler optical absorption spectroscopy (UV-DOAS) to monitor air quality; uses fast Fourier transform analysis to monitor particulate matter in effluents released from stacks
• Geographic information systems and global positioning – Uses optics and photonics in imaging and image processing to refine atmospheric and space-based images
• Information technology – Uses optics for data storage, ultrafast data switching, and (especially) transmission of data across fiber-optic networks
• Chemical technology – Relies on molecular optical spectroscopy for analysis and on ultra-short laser pulses to induce fluorescence; chemical vapor deposition and plasma etching support photonics thin film applications
• Transportation – Uses optics for monitoring exhaust emissions to ensure the integrity of shipping containers arriving from foreign ports, and navigation with ring laser gyroscopes
• Homeland security – DNA scanning, laser forensics, retinal scanning, identification of dangerous substances, optical surveillance
• Manufacturing – Laser welding, drilling, and cutting; precision measurements
• Biotechnology – Optical spectrometers and other optical devices are being used to verify biochemical compositions and monitor biotech processes.
• Solid State Lighting – Light-Emitting Diodes (LEDs) are replacing incandescent bulbs because of their low efficiency and compact fluorescent lighting (CFLs) because of their exposure of mercury to the environment. The cost of LEDs for outdoor lighting, traffic lights and indoor commercial and office use is now cost effective.

 [More to come ...]