We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What are Photodetectors?

By Adrien-Luc Sanders
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Photodetectors are devices capable of sensing electromagnetic energy, typically light, which contains photon particles that are a type of electromagnetic energy. Although there are many types, the most common are mechanical, biological, chemical. Photodetectors can also be used as thermometers — to measure radiation, to generate voltage, to amplify an existing current, and to record images. Plants even use a form of photodetection to guide their growth, as their cells react to the light and grow towards it. Whether natural or artificial, all photodetectors share a common principle: a reaction triggered by the presence of light.

An example of a mechanical sensor of this sort would be a laser security system that detects the presence of laser light, and its interruption, to determine intrusions and trigger an alarm. The most commonly known biological sensor is the eye, which detects and reacts to light to interpret optical signals, which it then sends to the brain as an image. Photographic film is one of the simplest forms of chemical sensors — it uses light to imprint an image onto its surface. Photographers develop their film in darkrooms to avoid ruining it, should the film have a chemical reaction to the light.

With a wide range of uses, photodetectors appear everywhere from particle-detecting telescopes to the Large Hadron Collider to UV-sensitive sunglasses. The majority of photodetectors are calibrated to detect light and radiation on a very specific spectrum, ranging from ultra-violet to infrared. Infrared devices, such as heat sensors and television remote controls, use light on the infrared spectrum to transmit a signal, which is captured and interpreted by a detector. When a button is pressed on a television remote control, the remote control emits an infrared signal on a wavelength invisible to the human eye. The television intercepts and interprets the signal as a command to turn the volume down, change the channel, or turn power on or off.

Depending on their purpose, photodetectors can have a variety of other functions. For example, semiconductors and semiconducting circuits use photodetectors to conduct an electrical current by changing light into electricity. When the semiconductor is exposed to light in its target spectrum, the semiconductor material absorbs photons that act on electrons to separate electron-hole pairs and create electrons in an excited state. This outcome allows the electrons to travel freely as a conductive medium, which creates a photocurrent. This conductive action makes semiconductors a key base component of virtually all modern electronics.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Discussion Comments

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.