The second part of this series on science fiction technology is about energy fields. Manipulated energy in one form or another has been a catch-all plot device in scifi for decades. It especially serves as stand-in solution whenever a more solid explanation of the action is unavailable. Science continues to advance with science fiction in mind, and many ideas that started speculative have since turned into hard science fact. Three of the most classic examples are below.
Part 2: Energy Fields
Force Fields
Force fields, energy shields, and deflectors are labels for a barrier made or pure energy or a combination of charged particles which are designed to protect an object or person. Sometimes the 
fields are described as small and hand-held, like a medieval shield that only covers part of the body, or a force field can be large enough to envelop an entire space ship. Usually these energy barriers are said to be invisible, though in many stories they become opaque when impacted. In both of Edward E. “Doc” Smith‘s classic Lensmen and Skylark series the fields would change color as they took damage to signify how soon they would fail.
Scientists are already looking to force fields as a means of protecting spacecraft, and potential occupants, from the dangers of space. Once outside the Earth’s magnetic field, a craft has little resistance to damaging radiation from the Sun. But if a portable magnetosphere could be generated around a craft, it would provide a barrier against charged particles. This would make extended space travel much safer, and specifically aids in planning for human travel to Mars.
Down on the ground, similar electromagnetic armor is being developed to protect military vehicles from rockets and ammunition. Incoming threats would be automatically identified, and the protective field would be activated at just the split-second needed to repel incoming projectiles or fired rounds. Because the field is turned on for only a moment, the energy requirements for the system are quite low. Once this tech matures, it seems inevitable that smaller versions will be produced for humans to wear.
Tractor Beams
When not using energy fields to repel dangers, science fiction instead uses it to grapple and hold. From alien abductions to Star Trek the tractor beam is the scifi standard for magically moving stuff around. It also has early origins in E. E. ‘Doc’ Smith’s books, but 
the tech became a stable in the public psyche with depictions in Star Wars and Star Trek.
Tractor Beams of today are called optical tweezers and function at a microscopic level. Implementations of this technology have been around since the late 1980s, but only recently have advances moved from experiments to practical use. In 2007, MIT researchers applied optical tweezers to move objects on the surface of microchips and proved it could be used as a real tool. Just this month Tel Aviv University demonstrated an optical tweezers device that could manipulate up to 300 nanoparticles at a time, such as beads of glass or polymer.
Cloaking Fields
Also called invisibility cloaks or stealth devices, cloaking fields deflect light around an object, and as long as no light is reflected or absorbed, the object will not be seen. This idea is usually implemented in science fiction as either the above ideal, as in Star Trek, or by using active camouflage to simulate the scene around a cloaked object. A 
good example of the later is the “mimetic polycarbon” body suit in William Gibson’s Neuromancer that changes pattern to match its surroundings, or of course the cloaking device in Predator.
Real cloaking fields have been in active for some time now, but not in the visible-light spectrum. The dark radar-absorbing paint on stealth aircraft doesn’t stop visual identification, and surfaces cooled to minimize electromagnetic emissions only defend against infrared. True invisibility is coming though. The British Army tested optical camouflage to create an invisible tank in 2007. The following year researchers at the University of California at Berkeley announced materials that can control the direction of light. And just last year multiple research groups announced the creation of invisibility cloaks that allow light to flow around a hidden object. The scale is still very small, but it’s clear we will be manipulating light in the future.
