- 3514 - TERAHERTZ WAVES - hold a lot of data? The electromagnetic spectrum covers everything from radio waves and microwaves, to the light that reaches our eyes, to X-rays and gamma rays. The only thing that changes is frequency and wavelength. But the higher the frequency the higher the energy.
--------------------- 3514 - TERAHERTZ WAVES - hold a lot of data?
-
--------------------------------------- E = h * f
-
- Energy equals thePlanck’s constant times the frequency. The terahertz band lies in a slim region of the electromagnetic spectrum between microwaves and infrared. Tera is 10^12, or 1 followed by 12 zeros. Hertz is cycles per second. So terahertz s very high frequencies.
-
- Radio waves are crucial for communication, especially between electronic devices, making them universal in today’s electronics. Light powers the optical fibers that underpin the internet. These realms of technology typically feed off different wavelengths, and uneasily coexist in the modern world.
-
- Both realms struggle to go far into the terahertz neutral zone. Standard electronic components, like silicon chips, can’t go about their business quickly enough to make terahertz waves. Light-producing technologies like lasers, which are right at home in infrared, don’t work with terahertz waves either.
-
- Even worse, terahertz waves don’t last long in the Earth’s atmosphere. Water vapor in the air tends to absorb terahertz waves after only a few dozen feet of travel.
-
- There are a few terahertz wavelengths that can squeeze through the water vapor. Astronomers have built telescopes that capture those bands, which are especially good for seeing interstellar dust. For best use, those telescopes need to be stationed in the planet’s highest and driest places, like Chile’s Atacama Desert, or outside the atmosphere altogether in space.
-
- When it comes to tapping into terahertz waves, the world of electronics faces a fundamental problem. To enter the gap, the silicon chips in our electronics need to pulsate at trillions (10^12)of cycles per second (terahertz).
-
- The chips in your phone or computer can operate perfectly well at millions or billions cycles per second, but they struggle to reach the trillions. The highly experimental terahertz components that do work can cost as much as a luxury car.
-
- The other realm, the world of light, has long sought to make devices like lasers that could cheaply create terahertz waves at specific frequencies.
-
- In 1994, scientists invented the “quantum cascade laser” , which was particularly good for making infrared light. In 2002, scientists succeeded in making a terahertz quantum cascade laser . But there was a catch: The system needed temperatures around -343 degrees Fahrenheit to actually fire. It also required liquid nitrogen to work, which made it difficult to use outside the lab or cryogenic settings.
-
- In the two decades since, that temperature threshold has crept up. The latest lasers operate at 8 degrees Fahrenheit. That’s not quite room temperature, but it’s warm enough that the laser could be chilled inside a portable refrigerator and carted out of the lab.
-
- In 2019, a team from Harvard, MIT, and the US Army created a shoe box-sized terahertz laser that can alter molecular gas.
-
- A nanoplasma chip made in 2020 was able to transmit 600 milliwatts of terahertz waves.
-
- What’s happened over the last thirty years is that progress has been made from both ends. The two realms trying to enter the terahertz dark zone from either end remain largely separate.
-
- Some of those abilities could speed up communication. Your Wi-Fi runs on microwaves. Terahertz, with higher frequencies than microwaves, could forge a better connection that’s orders of magnitude faster. Through a wire, it could also create a lightning-fast cross between USB and fiber optics.
-
- Terahertz waves are also ideal for detecting substances. Almost every molecule has a ‘fingerprint’ spectrum in the terahertz frequency range. That makes terahertz waves optimal for picking out chemicals like explosives and the molecules in medicines .
-
- Astronomers already use that ability to look at the chemical compositions of cosmic dust and celestial objects. Closer to Earth, a terahertz “electronic nose” that could even discern odors in the air.
-
- Those terahertz signatures also make the far infrared ideal for scanning people and objects. Terahertz waves can see through stuff that light can’t, such as clothes, with the bonus of avoiding potentially harmful ionizing radiation like X-rays. Security screeners or example.
-
- The one scanning characteristic that terahertz waves lack is that they can’t get through water in the air and in the human body. But that’s no obstacle for medicine. A doctor could use a terahertz device to screen for subtle signs of skin cancer that X-rays might miss; or a neuroscientist might use it to scan a mouse brain.
-
- A terahertz “electronic nose” that could even discern odors in the air.
-
- Much of the terahertz gap remains a blank spot on researchers’ maps, which means equipment using the coveted far infrared waves just isn’t common yet. Researchers really don’t have a lot of chances to explore what terahertz waves. But they can be good at using their imagination.
-
March 24, 2022 TERAHERTZ WAVES - hold a lot of data? 3514
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ---
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Friday, March 25, 2022 ---------------------------
No comments:
Post a Comment