Innovations In Light: Human Endeavours In Harnessing The Photon And Riding The Optical Wave

Here in the northern hemisphere, as the evenings get ever longer and the weather brightens, we’re starting to get more light into our lives again. So for us, UNESCO’s International Day of Light, on May 16, seems well timed: it celebrates the role that light plays in science, culture and art, education, and sustainable development.

The date represents the anniversary of the first successful operation of the laser in 1960 by physicist and engineer, Theodore Maiman, and to commemorate the day, we reflect on some of the most significant inventor contributions to the development of optics and photonics over the years, taking a closer look at some game-changing patents that have shaped the modern world. We end by thinking ahead to how history might see the contributions of the present day.

The foresight for starlight
We begin with a patent application that, in spite of its significance, did not make its way to grant. Hans Lippershey, a lens maker from the Netherlands, was the aspiring inventor and first to apply for a patent for the telescope, in 1608. Lippershey’s kijker ‘looker’ could magnify objects three times, and, according to his tale, was conceived after watching children in his shop playing around with his lenses to see a far-off weathervane.

Although he was first to file, the Dutch government recognised that several others had created devices of similar design, and so Lippershey was not awarded a patent. He was, however, generously rewarded by the Dutch government and inspired scientists and inventors across Europe, including Galileo, to obtain a copy of his work. Whether or not Lippershey was the true inventor, Galileo himself in his seminal work The Starry Messenger confessed that Lippershey’s design led him to his own telescope invention, thereby facilitating the observations that revolutionised human understanding of the laws of the Universe. How’s that for invention impact!

A lightbulb moment in patent litigation
In January 1880, a certain Thomas Edison was granted US patent 223898 for an electric lamp with a carbon filament. Later that same year, the application for UK patent 4933 was filed by Joseph Swan for a vacuum bulb having a cotton thread filament treated with sulphuric acid.

Negotiation in subsequent infringement actions concerning these patents – Swan vs Edison in the UK and Edison vs Swan in the US – ended in a merger between rival companies creating The Edison and Swan Electric Light Company. The new company produced a superior lightbulb having Swan’s bulb and Edison’s filament - an early lesson that technology can often be better served by collaboration, rather than conflict, between rival patentees.

Serendipitous solar cells
In 1839, a 19-year-old Edmond Becquerel discovered the photoelectric effect and created the world's first photovoltaic cell. This work created the basis for Albert Einstein’s Nobel Prize-winning work in 1907 explaining the theory behind the effect.

The dawn of the modern solar cell came over a hundred years after Becquerel’s discovery as a result of the use of semiconductors during World War II. Russel Ohl, at Bell Telephone Labs, was investigating the use of silicon rectifiers as radar detectors. However, when a silicon sample was exposed to a bright light, Ohl found that the current in the sample spiked.

Ohl and his colleague, Jack Scaff, found that a phosphorous impurity in the sample resulted in slightly increased number of electrons, while a Boron impurity led to a slightly decreased number. They called the regions ‘n-type’ (for negative) and ‘p-type’ (positive), and the boundary where these impurities met a ’p-n junction’.

They discovered that light striking this junction stimulated electrons to flow across the p-n junction, resulting in an electric current. In June 1946, Ohl was awarded US patent 2402662 for a process of forming silicon that led to the first p-n junction cell, which is the basis for most modern solar cells.

In 2022, solar PV electricity generation accounted for over 5% (over 1000 TWh) of total global electricity generation. With recent per-annum growth of around 25%, we could be looking at 30% global solar PV energy production by 2030 – an astonishing figure surely beyond Becquerel, and even Ohl’s, wildest dreams.

Nobel-prize-winning holography
Known as the Father of Holography, Hungary’s Dennis Gabor filed dozens of patent applications between 1928 and 1972, including US3600054A for Holographic Associative Memory Permitting Conversion of a Pattern to a Machine-Readable Form.

An engineer, inventor and futurist, Gabor developed holography while working on improvements for the electron microscope. When faced with the limitations of the electron microscopes, Gabor came up with a solution to capture a limited electron image which contained all the information needed, and then to correct the image using optical means.

To do this, he developed a way of first recording an interference pattern between the microscope’s electron beam and a coherent reference wave. He dubbed this recorded interference pattern the hologram from the Greek for ‘whole’, because it contained the whole of the electron beam’s information (i.e., its amplitude and phase). The next step included illuminating the hologram with visible light, in order to reconstruct the original wavefront.

Gabor was awarded the Nobel Prize in Physics for his invention of the holographic method in 1971, the same year in which US3600054A was published.

Sci-fi predicts the future
Perhaps the better-known modern use of holography is in display screens to provide a three-dimensional image. A technology that no doubt captures the imagination of so many, inspired by Princess Leia’s projected message to Obi-Wan Kenobi in A New Hope as well as countless other examples in sci-fi TV shows and films, holographic displays have become a modern reality.

A major contributor in the field of holographic displays, and inventor of US patent 10775741 relating to collocated imaging and display pixels as well as more than 60 others, Mary Lou Jepsen is a modern-day star of the holographic scene. Having led research group Google X and helped develop Oculus, Jepsen is now taking on medical imaging at her company OpenWater, allowing doctors to observe the inside of the human body to assist with early diagnosis of stroke and traumatic brain injuries.

Ablating through racial and gender divides
Light also finds uses in other well-known modern medical technology, arguably most famously in laser eye surgery. One of the most ground-breaking laser eye surgeries was pioneered by Dr Patricia E. Bath in the 1980s. The technique, known as Laserphaco (short for ’laser photo-ablative cataract surgery’), uses a laser beam to safely vaporize cataracts in a patient's eye with only a single incision. The method and apparatus were the subject of Bath’s US patent 4744360 issued in May 1988.

Dr Bath went on to be the first African American Resident at New York University, and also founded the non-profit American Institute for the Prevention of Blindness in Washington, D.C. She is also an inventor named on four other patents.

To put her outstanding achievements into further perspective, in her own words, “Sexism, racism, and relative poverty were the obstacles which I faced as a young girl growing up in Harlem. There were no women physicians I knew of and surgery was a male-dominated profession; no high schools existed in Harlem, a predominantly black community; additionally, blacks were excluded from numerous medical schools and medical societies; and, my family did not possess the funds to send me to medical school.”

You say maser, we say laser…
We end our look, back at where we began - with the emergence of the laser. Although the first to build a working laser, Theodore Maiman was not the first owner of a laser-related patent. On 22 March 1960, scientists Charles H. Townes and Arthur L. Schawlow were granted US patent 2929922 for their maser. An optical maser is known today as a laser, and thus, while Maiman retains the coherent limelight, Townes and Schawlow were first to publish (and patent) the underlying concepts.

A cautionary tale
The laser story does not quite end there - Columbia scientist Gordon Gould came forward with a research notebook that he claimed proved he had the initial idea for the laser in November 1957. His unpublished notes were the first to coin the acronym LASER ‘light amplification by the stimulated emission of radiation’. Gould fought for the rights to the original Townes and Schawlow patent under the US then ‘first to invent’ system but was ultimately unsuccessful due to a finding of lack of enablement in his notes. Gould’s second mistake was believing that he needed to build a working laser to be able to obtain a patent and this prevented him from filing before Townes and Schawlow. A cautionary tale that warns all optics and photonics engineers that it can be vital to consult a patent attorney for advice as soon as possible after devising an invention.

Innovations for tomorrow’s history books
Looking ahead – will history tell our children of the wonder of our generation’s innovation? And with so much already achieved in optics and photonics in the last century in particular, has there been anywhere left to explore in today’s world? Looking at innovation and the global market today, the answer to both these questions is a resounding (or is it resonant?) yes.

A silver lining of the COVID-19 period appears to have been the beginning of a golden era for the optics and photonics market: valued at around USD 500 billion in 2020, the global photonics market grew by over 20% the following year and is expected to reach over USD 1000 billion by 2027.

This growth has been driven by an explosion of innovation over the past few years in particular. Advances in fibre optics and silicon photonics are driving the ever-higher data transfer capabilities that facilitate growth in almost every other area of the high-tech economy. Optical computing is on the verge of beating quantum computing to the mark in data encryption and data processing in the world of finance. AR and heads-up displays as well as gesture-based user-machine interfaces are allowing technology to permeate reality in ways we only dreamed of less than a generation ago. Outstanding advances in space telescope design are helping us to understand the very nature of the origins of the Universe and we could begin to see even further into the past with innovations in mirror design taking place already this year. LiDAR, used for decades in meteorological applications, is now at the forefront of driverless car technology as well as finding new applications in surveying climate and ecology to turn the tide of human opinion and help us save our planet.

From the first view of Mars through a telescope in 1609 to the first scan of the planet surface by helicopter-mounted LiDAR and from the humble filament bulb to the transparent OLED pixel we have certainly come a long way in the world of optics and photonics. It’s hard to resist looking forward to a rewrite of this article in decades’ time looking back at what today’s future had in store for us.