From The Editor | December 6, 2023

2023's Best: Methane Super Emitters, The Valley Of Death, Hidden Cities, And Maple Syrup

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By John Oncea, Editor


It’s that time again. Let’s take a look at the most-read articles that appeared on Photonics Online this year. It’s got intrigue, suspense, and surprises. Oh, and infrared, LiDAR, and so much more.

As a guy who can’t remember what he ate last night* writing a year-end retrospective detailing the highs and lows, hits and misses, wins and losses in #Photonics2023 is, well, not fun. But it has to be done, right?

So, instead of trying to remember what happened let’s use the magic of Google analytics and take a look at what resonated with you, or reader, quarter by quarter.

* It was graham crackers and butter — long story.

Start The Year Off Right

The most-read article during the first three months of 2023 was about how NASA’s EMIT mission accidentally discovered methane super-emitters from space. Using an imaging spectrometer aboard the International Space Station, NASA identified “more than 50 methane ‘super-emitters’ in Central Asia, the Middle East, and the Southwestern United States.”

The spectrometer was built primarily to identify the mineral composition of dust blown into the atmosphere from Earth’s deserts and other arid regions by measuring the wavelengths of light reflected from the surface soil in those areas. That study, NASA’s Earth Surface Mineral Dust Investigation (EMIT) will help scientists determine whether airborne dust in different parts of the world is likely to trap or deflect heat from the sun, thus contributing to the warming or cooling of the planet.

More than a year later, according to NASA’s Jet Propulsion Laboratory, “Data from NASA’s EMIT instrument is now being used to identify point-source emissions of greenhouse gases with a proficiency that has surprised even its designers.”

The EMIT science team creates maps of methane plumes to help identify their source. These maps are made available on a website, and the underlying data can be accessed at the joint NASA-United States Geological Survey Land Processes Distributed Active Archive Center (LP DAAC). The data collected by the mission is open to the public, scientists, and organizations for use.

“Since EMIT began collecting observations in August 2022, it has documented over 50,000 scenes,” writes NASA. “The instrument spotted a cluster of emissions sources in a rarely studied region of southern Uzbekistan on Sept. 1, 2022, detecting 12 methane plumes totaling about 49,734 pounds (22,559 kilograms) per hour.”

On September 3, 2022, the instrument detected plumes in a remote area of southeastern Libya that were much smaller than anticipated. One of the smallest sources found was emitting an estimated 979 pounds (444 kilograms) per hour, based on local wind speed calculations.

Rounding out the top five most-read stories was this one on secret experiments on board X-37B, answering the question if LiDAR should be the go-to technology when it comes to driverless cars, a look at the who, what, and where behind photonics’ explosive growth, figuring out if we’re ready for quantum computing, and Gentec Electro-Optics’ offering of quick guide to calculating laser fluence.

April Showers Bring … A Walk Through The Valley Of Death?

The second quarter of 2023 saw this article trying to answer the question if directed energy weapons will survive the valley of death or not come out as most read. I won’t spoil the ending but, for those of you who don’t want to click through, the key quote is from Mark E. Solomons, Office of the Undersecretary of Defense for Research and Engineering, who said, “If ever there was a weapon system capability that needed moving across the valley of death, DE is it.”

Suffice it to say, DEWs are going to make it through the valley of death. According to Breaking Defense, the Missile Defense Agency (MDA) is already putting “increased emphasis” on the development of DEWs for shooting down adversary missiles.

“I think part of [why] the Missile Defense Agency in the past few years kind of backed away was that technology … needed to mature in power levels that could be delivered on target, and needed to (reduce) the size, weight, and power requirements to produce the directed-energy effects,” explained Laura DeSimone, MDA executive director. “Directed energy shows great promise for the future. I mean, there are so many advantages of having a potential directed-energy engagement system — give the warfighter additional engagement opportunities, save interceptors, and lower cost per engagement. So, lots of great potential for directed energy.”

The next four most-read articles include four unique uses of Raman spectroscopy, how the U.S. military is using quantum technologies to keep its edge, Schneider Optics’ article on taking the mystery out of lends modulation transfer function (MTF), and Alluxa’s look at angle of incidence (AOI) and polarization.

Like Seven Inches From The Midday Sun

Summer came and brought with it this article on how LiDAR was responsible for uncovering the ancient city of El Mirador – as well as finding long-forgotten roads and guiding robot dogs – as the most read between July and September. This also was, by the way, the most-read article of the year!

LiDAR has been utilized by researchers in Guatemala since The Mirador Basin Project, launched in 2015, conducted two extensive surveys of the southern section of the basin, with a focus on the historic city of El Mirador. The outcome of this project was the mapping of 658 square miles (1,703 square km) of this area of the country.

“When I generated the first bare-earth models of the ancient city of El Mirador, I was blown away,” Carlos Morales-Aguilar, a postdoctoral fellow in the Department of Geography and the Environment at the University of Texas at Austin said. “It was fascinating to observe for the first time the large number of reservoirs, monumental pyramids, terraces, residential areas, and small mounds.”

Other stories that resonated with readers over the summers included this look at how NASA and ESA are using photonics in space, the use of a dual-property coating to prevent fogging and unwanted reflections for LiDAR applications, hyperspectral imaging’s role in life sciences, and the varied ways SWIR, MWIR, and LWIR are being used today.

Baby, It’s Cold Outside (Sticky, Too)

There are still a couple of weeks left so things may change but a deadline is a deadline. So, with that legalese out of the way, we can proclaim this article on the use of infrared (IR) at the border and whether or not it could have taken down the Canadian cartel. As I note in the article the answer is a shoulder shrug, but the story was a hoot.

I also detailed how the Border Patrol uses IR at borders to detect potential intruders or smugglers in low-light conditions, as well as how IR technology is used in thermal imaging cameras to produce a clear image in practically all weather conditions. All said we touch on eight ways IR is being used by the Border Patrol.

The number two through five most-read articles starts with a look at how NASA used high-speed cameras, followed by a personal favorite, Everybody Love LiDAR. NIST’s development of a superconducting camera 400 times more powerful than any other device of its type was number four, followed by Mad City Labs article on the benefits of hands-on quantum computing learning by Aedan Gardill, Ph.D.

On A Personal Note

All of the above is what you, our readers, interacted with the most and was put together by pure, stone-cold analytics. “But what were your personal favorites,” you may be asking.

Well, I wasn’t going to say but since you asked, I enjoyed writing about the lighting rod and lithium niobate photonics; Quantum, Ant-Man, and the Wasp; tracking wildfires; etymology; Nobel Prize winners and Halloween; the Hallmark-esque masterpiece created with the help of AI; and the already-mentioned Canadian Cartel story.

But my two favorites were the story behind the Wow! Signal and the race to build Project Orion. I hope you enjoyed reading all of what I wrote as much as I enjoyed writing it. And please don’t hesitate to send me an email ( or connect with me on LinkedIn if you have something you’d like me to write about.

Thanks for a great year and here’s to an even better 2024!