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
Apr 18, 2021
https://youtu.be/afv9_fRCrq8 Made at Target Oakridge (camera Ziyue Zhang) Monday: "Targeting" the Open Compute Project Tuesday: NUMECA, Computational Fluid Dynamics...and the America's... [[ Click on the title to access the full blog on the Cadence Community s...
Apr 16, 2021
Spring is in the air and summer is just around the corner. It is time to get out the Old Farmers Almanac and check on the planting schedule as you plan out your garden.  If you are unfamiliar with a Farmers Almanac, it is a publication containing weather forecasts, plantin...
Apr 15, 2021
Explore the history of FPGA prototyping in the SoC design/verification process and learn about HAPS-100, a new prototyping system for complex AI & HPC SoCs. The post Scaling FPGA-Based Prototyping to Meet Verification Demands of Complex SoCs appeared first on From Silic...
Apr 14, 2021
By Simon Favre If you're not using critical area analysis and design for manufacturing to… The post DFM: Still a really good thing to do! appeared first on Design with Calibre....

featured video

The Verification World We Know is About to be Revolutionized

Sponsored by Cadence Design Systems

Designs and software are growing in complexity. With verification, you need the right tool at the right time. Cadence® Palladium® Z2 emulation and Protium™ X2 prototyping dynamic duo address challenges of advanced applications from mobile to consumer and hyperscale computing. With a seamlessly integrated flow, unified debug, common interfaces, and testbench content across the systems, the dynamic duo offers rapid design migration and testing from emulation to prototyping. See them in action.

Click here for more information

featured paper

Understanding the Foundations of Quiescent Current in Linear Power Systems

Sponsored by Texas Instruments

Minimizing power consumption is an important design consideration, especially in battery-powered systems that utilize linear regulators or low-dropout regulators (LDOs). Read this new whitepaper to learn the fundamentals of IQ in linear-power systems, how to predict behavior in dropout conditions, and maintain minimal disturbance during the load transient response.

Click here to download the whitepaper

Featured Chalk Talk

Smart Embedded Vision with PolarFire FPGAs

Sponsored by Mouser Electronics and Microchip

In embedded vision applications, doing AI inference at the edge is often required in order to meet performance and latency demands. But, AI inference requires massive computing power, which can exceed our overall power budget. In this episode of Chalk Talk, Amelia Dalton talks to Avery Williams of Microchip about using FPGAs to get the machine vision performance you need, without blowing your power, form factor, and thermal requirements.

More information about Microsemi / Microchip PolarFire FPGA Video & Imaging Kit