This week's guest blogger is Anthony Haugh who currently lives in New Mexico, and has studied Electronics Technology and Photonics Technology. He later plans on obtaining his third degree in Optical Engineering after visiting Europe. He can be found on Twitter as @Boltary.

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To my eternal amusement, every time someone asks me "what are your majors?" I get blank stares when I give the reply "Photonics Technology and Electronics Technology." Most of everyone I meet immediately understands the degree with that now-commonplace word "Electronics," but almost without exception I am asked "What is Photonics?" I admit that when I entered college I only had a limited understanding of what "Photonics" was besides Photons and Lasers. Even my spell-checker says it is a made-up word, so what is Photonics, and why is it important?

It turns out that "Photonics" is an extremely diverse field, and is about as vague as saying "Chemistry" or "Physics" when trying to talk about a field of science. Specifically, photonics is a sub-set of physics that focuses on the studies and applications of photons (Such as detection, generation, etc). Photons are odd little concepts that defy simple classification by being neither a wave nor particle. Composed of an electric component and a magnetic component and called "light," they offer the opportunity to be a headache to almost any scientist or engineer in most fields thanks to modern technology. You can also say it is the "Study of Electro-Magnetic Radiation" if you need to sound impressive to a Fine-Arts student.

While light as a subject has been discussed as far back as B.C.E. it is only relatively recent that we have begun to use it in a wide-spread technological fashion. The word "Optics" is perhaps the first stepping stone in this field, as optics are the first instruments devised to control and understand light. Optics manipulate light in a straightforward fashion, whether it is from a mirror reflecting, a lens expanding/focusing, or a prism refracting. Optics were among the core of the first "advanced" tools of science, from telescopes to microscopes. It offered a way to better understand your environment by exploiting how light worked.

Figure 1: Courtesy of Chris Madden

As technology progressed, the mechanical tools that were so prevalent in society were augmented and even sometimes entirely replaced with electronic equivalents. Electronic applications revolutionized the ability to solve problems and create new ones, and soon were common place everywhere one went. In the mid-20th century though, an entirely new way to design systems and tools was brought to the attention of the scientific community; the Laser. The laser emerged in the 1960s as the first true photonic device. Diverging from previous optics with manipulated light that was already present, the laser not only generated light but also did so in a unique fashion in that the photons were (for the most part) amplified coherent emissions as opposed to the random spontaneous emissions found in a common light bulb. The laser proved that light could be more then merely redirected or randomly generated, it could be harnessed and controlled, to be used for more then a mere detector, but also as a way of being a tool in and of itself.

Together with other photonic inventions such as fiber optics, the laser quickly pervaded most technological fields just as electronics did previously. Photonics offered alternative and unique ways to solve problems and design systems that were previously only possible with electronics. A powerful and unique alternative, it has today as a field become commonplace in modern society. Fiber optics is an example of a photonics application that is phasing out large-scale electronic-based communications (Even cars are replacing wires with fiber optics¹). Not only can it be found replacing electrical telecommunications due to being cheaper, lighter, smaller, sporting slower dB losses and able to go places easier (like underwater or through a fuel tank, not ideal for an electrical line), as well as being able to locate breaks easier.

Running with the previous example of fiber-optics, while an electrical communication system relies on the stretch of broken cable being found, and a worker ripping up the entire stretch to find and correct the break, a fiber-optic equivalent system can tell the worker exactly where the break occurs with an OTDR² which uses the reflection of light to identify down to mere millimeters where the error is (useful for a 2km stretch of cable). Unique advantages such as this is why photonics is considered so important in the modern world of technology.

Figure 2: Courtesy of The Fiber Optic Association; an example of copper cables versus the fiber-optic equivalent.

Lasers are perhaps the most popular and renown application of photonics, and are admittedly a significant reason of why I chose photonics as one of my degrees. Beyond the simplistic destructive capabilities (such as fond memories of cutting through firebrick in seconds) or being used for etching and drilling, it can also offer a way to actually protect something, such as being a novel way to cool a system down via Laser Cooling and Trapping³. A fascinating example of an application unique to photonics is the ability to move a non-magnetic particle without physically touching it, via a Optical Levitation trap that uses the momentum of a photon to overcome the force of gravity on a particle. This is widely used in biology where physically touching a particle or small organism can often damage or contaminate it.

To summarize, photonics is the use of photons for an extremely diverse technological portfolio of applications, covering optical tweezer, propulsion systems, welding, lithography, communication, sensors ranging from light types to distances to temperature, holography, fusion and so much more. It is the lesser-known cousin of optics, and I hope I shed some new light on this sometimes overlooked field.

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1.) BMW OPS: OBD Autoscan http://www.bikudo.com/product_search/details/315930/bmw_ops.html

2) What is an OTDR?: White, David: http://www.wisegeek.com/what-is-an-otdr.htm 10/10/2010

3) Laser Cooling and trapping of neutral atoms: Phillips D. William: http://physics.nist.gov/News/Nobel/NobelLec.pdf Reviews of Modern Physics, Vol. 70, No. 3, July 1998