Lasers and Leaves

International Year of Light 2015

Looking back, my career path was not determined by some grand plan, but rather by the beauty of the light from an argon ion laser in our Applied Physics Department. It wasn’t the science that the laser was bought for, Raman spectroscopy, or an understanding of how the laser would change the world, that drew me.

At the time I was soon to graduate with a physics degree – the first in my family history to get a science degree – and was interviewing with a local branch of IBM where my love of mathematics might give me an edge and where I might find stimulating work in Northern Ireland. But fate intervened and I was seduced by the light, by the pure intense green beam, and lasers became my thing. Mentioning lasers also gave some sort of defense against the many enquiries from caring relatives on when was I going to get a real job.

Another indelible memory; an important insight came to me in 1980 when I was at the home of my boss at the time, Dick Daly, founder of an early laser company. It was the fall (autumn to some) on Long Island, NY, which meant leaves everywhere. Dick pointed to one of his huge piles of leaves and said with his characteristic grin, “One of my photon stores”. The concept of storing photons was of great interest to laser jocks like Dick and me. Short-pulse high-power lasers benefit greatly from materials that can hold a lot of energy. But Dick’s observation was way beyond the world of lasers and has caused me to think since about the profound relationship between light and life. The chloroplasts in leaves use the photons from the sun to convert carbon dioxide into oxygen and carbon. All of our forests, our plants have been busy “sequestering” carbon dioxide for hundreds of millennia, while tuning our atmosphere to be human friendly.

It takes the energy from many photons to grow a leaf, but at the end of the day, what a leaf is, is mostly a carbon based organic structure built by light. This lesson from one of my many mentors led me to realize that as all fossil fuels started as vegetation, we are burning our way through earth’s store of photon energy from the sun, accumulated over 300 million years or more. With many processes and great lengths of time, nature has stored this photon energy from leaves, wood and other biomass in high density forms such as oil and coal. The high density is key to modern transportation, and collection of fuel for large centralized power plants. Now we have a formidable challenge to capture and store solar energy arriving today in ways that will challenge nature’s gifts. Nature had all that time to store photons; our version of solar energy is more “real time”. But the sooner that solar becomes a significant part of the global energy mix, the better for our planet, for all of us.


International Year of LightDr. Eugene Arthurs, CEO of SPIE, the international society for optics and photonics.

Aside from SPIE, he is also a member of the Photonics21 Board of Stakeholders, where he is directly involved in the European Commission’s Horizon 2020 and the entity for a public-private partnership (PPP). Prior to these responsibilities, Eugene has held many positions at esteemed scientific technology organizations in both the US and Europe, and has served on several boards in the realm of optics, photonics, and scientific development.

 

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One thought on “Lasers and Leaves

  1. Eugene, what a great story!
    I can’t help but remember your once mentioning in a meeting at Oriel “invisible green light” emitted by a laser, and I asked you “If it’s invisible, how do you know it’s green?!”
    Gene

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