editor's blog
Subscribe Now

Shine a Light

Light is full of energy; it’s just that we can’t do much with that energy directly. Whether we’re trying to use the energy to power our world or simply to detect the light itself, we have to extract it. This typically means converting the light to some other more useful form of energy.

There are two fundamental kinds of light conversion: ones that turn light into other light and ones that turn light into electric current or voltage.

The first category is referred to generically as luminescence. There are two kinds of luminescence, which depend on the light and material. When light is absorbed and immediately re-emitted at a different frequency, it’s called fluorescence – as seen in a fluorescent lightbulb. When the light is re-emitted more slowly over time due to illegal quantum state interactions of some sort that slow the process down, it’s called phosphorescence. The phosphorescent delay is familiar in glow-in-the-dark materials, where the light is absorbed and then re-emitted gradually.

When fluorescence involves ionizing radiation, like X-rays, which have enough energy to knock electrons out of an atom, then the resulting re-emission (in the visible range) is referred to as scintillation.

When converting light to electrical voltage or current, there are also several mechanisms. A very simple phenomenon is photoconductivity, where the conductivity of a material (in particular, a semiconductor) is improved because the energy of incident light is bumping more electrons into the conduction band.

There are two other closely-related effects that can result in electrons being knocked about. In the photovoltaic effect, electrons are transferred between bands, creating a potential between electrodes. With the photoelectric effect, the electrons are completely ejected from the atom and are free to roam about the cabin.

Leave a Reply

featured blogs
Jul 5, 2022
The 30th edition of SMM , the leading international maritime trade fair, is coming soon. The world of shipbuilders, naval architects, offshore experts and maritime suppliers will be gathering in... ...
Jul 5, 2022
By Editorial Team The post Q&A with Luca Amaru, Logic Synthesis Guru and DAC Under-40 Innovators Honoree appeared first on From Silicon To Software....
Jun 28, 2022
Watching this video caused me to wander off into the weeds looking at a weird and wonderful collection of wheeled implementations....

featured video

Synopsys USB4 PHY Silicon Correlation with Keysight ADS Simulation

Sponsored by Synopsys

This video features Synopsys USB4 PHY IP showing silicon correlation with IBIS-AMI simulation using Keysight PathWave ADS.

Learn More

featured paper

Addressing high-voltage design challenges with reliable and affordable isolation tech

Sponsored by Texas Instruments

Check out TI’s new white paper for an overview of galvanic isolation techniques, as well as how to improve isolated designs in electric vehicles, grid infrastructure, factory automation and motor drives.

Click to read more

featured chalk talk

The Composite Power Inductance Story

Sponsored by Mouser Electronics and Vishay

Power inductor technology has made a huge difference in the evolution of our electronic system designs. In this episode of Chalk Talk, Amelia Dalton chats with Tim Shafer from Vishay about the history of power inductor technology, how Vishay developed the most compact and efficient power inductor on the market today and why Vishay’s extensive portfolio of composite power inductors might be the best solution for your next embedded system design.

Click here for more information about Vishay Inductors