Programmable Quantum-Dot Arrays

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Science > Chemistry
Technology > Application > Everydaytech
Technology > Technology Levels > High Tech / Hitech
Technology > Application > Materials Technology

Image from John Edds
A Programmable Quantum Dot Array, displaying a surface with characteristics that cannot be found in ordinary materials

^{What's great about PQDA is that it can become [whatever] in a tiny fraction of a second, and when [whatever] is not needed anymore and something else is, it's gone and it's there: mirror *poof* thin-film camera *poof* solar panel *poof* phased array radar *poof* optical phased array laser *poof* superconducting film . . .
—User Testimony, JonE Future, 120 AT}

Introduction

A Programmable Quantum-Dot Array (PQDA) is an arrangement of variable quantum dots ¹ that are incorporated into the surfaces of electrically or photonically conductive nanostructured composite films and nanofibers².

Background

Quantum dots are three dimensional nano-scale structures in which charge carriers (electrons or electron holes) are quantum confined, forming 'artificial atoms' (a-atoms). The number of charge carriers that are confined in each quantum dot can be adjusted in real-time by electrical or photonic signals, ranging from one up into the thousands. The size, shape, and symmetry of these a-atoms can also be tuned to some extent.

Q-dot based a-atoms are significantly larger than the atoms of the classical chemical elements, which means that although they may have the same number of electrons as an atom of a particular element, an a-atom of that element has properties that are orders of magnitude weaker, or significantly different, than the natural version and thus they are not equivalent. In contrast to classical atoms, a-atoms do not have an atomic nucleus, which means that a-atoms (ignoring the substrate they are confined in) have a low mass that is dependent on the number of charge carriers that are present (electrons have a mass of approx. 1/1836th that of protons).

Despite this, quantum dots have been found to have a number of useful applications, demonstrating optical, electrical, and electromagnetic behaviors significantly different from larger particles. While early quantum dots had to be created with a particular desired property 'locked in', modern versions can change their structures, and therefore properties, as desired and in fractions of a second. Arranged together in large numbers, they form a surface whose every point can emit or absorb light, become semi or superconducting, or generate low power magnetic fields as desired and in variable arrangements that can employ as much or as little of the array as desired.

Image from John Edds
An ouro gelbot surface displaying optical and textural variegation

Modes and Applications

PQDAs are primarily laid down as films, layers, or ribbons on or within a variety of substrates, such as Ultimate Muscle fibers, utility fog, utility sand, MPTC and BAESFTLA structures, and VIMs. Ribbons and nanofibers are also woven (similarly to woven graphene) into bulk solids.

Because its electrical, magnetic, and optical properties can be adjusted in real time at a level of resolution from individual quantum dots to the sum total, at any given moment a PQDA can function as anything from computronium (analog, digital, and quantum), to photovoltaics, to an optical or radar phased array, to a thermal or optical camera, to a low power electromagnet, to a simple mirror. Or different sections of an array may be set to run different functions in parallel, providing multiple abilities simultaneously.

Whether operating as standalone devices or in combination with other technologies, this flexibility has led to a number of PQDA-based applications. Some particularly notable examples include:

Smart paint - A PQDA layer on top of control and power systems laid down on any convenient surface. Interior, all-weather, aquatic, bio-compatible, and deep-space versions are commonly available for everything from animated tattoos to spacesuits and ship hulls. Depending on operational mode, the PQDA layer can create:

High resolution 'reality level' displays (static or fully animated) with or without integrated touch controls on any part of the covered surface. Depending on the design, displays may be rigid or as flexible as cloth.

Optical and radio frequency sensors and communication systems from any point on the covered surface. Both technologies can operate across a wide range of frequencies, including ultraviolet and infra-red and can be instantly moved from point to point on the array or 'slide' across it while remaining active.

'Virtual cameras' able to provide a high resolution viewpoint from anywhere on the covered surface across a range of frequencies.

Photovoltaic arrays able to power/recharge the PQDA system or the substrate and structures it is attached to.

Photochemical thin-films, able to emit light, including laser light, to trigger chemical reactions or break chemical bonds.

When combined with utility fog or similar technologies, smart paint effects can also be created from any point within the fog volume. When integrated into a system of specialized nano and microbots programmed to self-organize when released into the environment, spray-on displays, cameras, sensors, and control surfaces become available.

In addition, with sufficient energy and cooling, PQDA-based optical phased arrays can generate weapons-grade lasers, although range and overall power is limited compared to dedicated systems.

Virtual bracing - used in magnetic or superconducting modes, a PQDA can shift from flexible to rigid and back again in a controlled manner and at any point within its structure. This effect is much weaker than in dedicated systems, but PQDA based devices are much lighter, making them useful in applications where it is desirable to keep mass to a minimum.

Virtual bracing is primarily used in lightsails and large telescope mirrors, whose components have thicknesses measured in microns. A PQDA layer along the back of the reflective surface allows it to flex without the use of more massive control lines or motors. This is particularly useful for light-sail systems but also has application in the larger telescope mirrors. Properly controlled, the PQDA layer can cause the mirror to flex and focus on a target location or cause different portions of the mirror to flex independently, allowing the telescope to observe multiple locations simultaneously.

Limitations

Although highly versatile and widely used, like all technologies PQDAs have both advantages and limitations. Like all nano-electronics, PQDAs must be protected inside shielding or employ active self-repair systems when operating in environments with high levels of ionizing radiation. Some of the systems that can be created by PQDAs have inferior properties and performance when compared to peak products created by other methods. For example, electro-magnets generated by a PQDA have field strengths orders of magnitude weaker than those formed from dedicated materials.

Beyond the creation of devices and systems that can be built no other way, the utility of PQDAs lie in their ability to create one or more desired items within nanoseconds and, when they are no longer required, replacing them nearly instantaneously with something else.

Footnotes

^{1. Quantum dots are three-dimensional nanoscale structures where electrons or electron holes are quantum confined. The confined charge carriers form artificial atoms. Quantum dots come in two fundamentally unique classes: fixed and variable. Fixed quantum dots have the number of confined charge carriers permanently fixed at the moment of their manufacture. In contrast, variable dots can have the number of charge carriers adjusted after their manufacture by external inputs.↩}
^{2. A typical PQDA nanofiber has a diameter of 60-80 nm and has 10-13 quantum dots around its circumference.↩}

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Development Notes

Text by John Edds
updated by Todd Drashner
Initially published on 29 February 2016.

Design Notes

Concept and design originally by Wil McCarthy and Gary E. Snyder.

https://patents.google.com/patent/US7655942B2
https://patents.google.com/patent/US7692180B2
https://en.wikipedia.org/wiki/Hacking_Matter

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