Light and Energy

The Physics of Light and Color - Light and Energy Section Overview:

The amount of energy falling on the Earth's surface from the sun is approximately 5.6 billion (quintillion) megajoules per year. Averaged over the entire Earth's surface, this translates into about 5 kilowatt-hours per square meter every day. The energy input from the sun in a single day could supply the needs for all of the Earth's inhabitants for a period of about 3 decades. Obviously, there is no means conceivable (nor is it necessary) to harness all of the energy that is available; equally obvious is that capturing even a small fraction of the available energy in a useable form would be of enormous value.

Review Articles

The topics discussed in this section are the photovoltaic effect and solar cells, photosynthesis, the photoelectric effect, solar cells, charge-coupled devices, fuel cells, and nuclear fusion.

The featured discussion is intended to aid in understanding the basics of light detection and to provide a guide for selecting a suitable electronic detector for specific applications in optical microscopy.

Electromagnetic radiation is derived from the electric and magnetic properties common to all forms of this energy, as manifested by the generation of electrical and magnetic oscillating fields as the waves propagate through space.

CMOS image sensors are designed with the ability to integrate a number of processing and control functions, which lie beyond the primary task of photon collection, directly onto the sensor integrated circuit.

A photomultiplier tube is a photoemissive device in which the absorption of a photon results in the emission of an electron and is useful for light detection of very weak signals.

Interactive Tutorials

The process of green plants synthesizing numerous complex carbon-based biochemicals used to sustain life is called photosynthesis. This tutorial demonstrates the basic molecular steps in the photosynthetic process.

Solar cells convert light energy into electrical energy either indirectly by first converting it into heat, or through a direct process known as the photovoltaic effect. This tutorial explores the basic concepts behind solar cell operation.

Fuel cells are designed to utilize a catalyst, such as platinum, to convert a mixture of hydrogen and oxygen into water. This interactive tutorial explores the major steps in fuel cell operation.

In a charge-coupled device (CCD) incident light must pass through various stages before it's absorbed into the silicon substrate. Examine the interaction of photons with silicon as a function of wavelength.

Explore the steps utilized in the construction of a charge-coupled device (CCD) as this tutorial examines and illustrates each individual stage in the fabrication of the CCD photodiode sensor element.

Full-frame charge-coupled devices (CCDs) feature high-density pixel arrays capable of producing digital images with the highest resolution available and is popular due to the simple design, reliability, and ease of fabrication.

This interactive java tutorial explores how in the end-on photomultiplier tube design, electrons are generated by the photocathode and amplified by passing through a dynode chain resulting in an end in the anode.

Contributing Authors

Kenneth R. Spring - Scientific Consultant, Lusby, Maryland, 20657.

Mortimer Abramowitz - Olympus America, Inc., Two Corporate Center Drive., Melville, New York, 11747.

Matthew Parry-Hill, John C. Long, Kirill I. Tchourioukanov, Robert T. Sutter, Christopher A. Burdett, Thomas J. Fellers and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.