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Researchers from the Princeton University have created the smallest laser possible. The laser emits microwaves and is termed as Maser. The laser has been developed using Quantum dots, which are a group of artificial atoms or semiconductor like nanocrystal material and are said to exhibit quantum mechanical properties. More specifically they have the quantum tendency of confining the atom’s electrons.
This quantum confinement property allows the energy of the nanocrystals to be measured by employing the particle in a box model, which facilitates the tuning of electrical and optical properties of these nanocrystals. From functional point of view this allows the nanocrystals to absorb lights of certain wavelengths and convert and emit them into lights of different wavelengths.
The team built a double quantum dot micromasar that paired four quantum dots and each pair was separated by a distance of 500 nanometers. Tiny wires were then connected between the dots enabling the unit to function as a transistor unit in which one dot served as a source, while the other operates as a drain or sink and the wires acted as the gate electrodes.
Then this setup was connected to a battery enabling a voltage drop that allowed current to move. This in turn could excite the electrons in the source dot and cause them to move through the wires and into the drain. As the electron flows through the wires, it yields a photon that has the characteristics of a microwave, which is in turn reinforced by other pairs of quantum dots then reflected off of mirrors and together built into a coherent beam of microwave emissions.
The primary objective of this research was not to develop a maser, but in essential to look up at how to use paired quantum dots or qubits. These qubits are the basic units of information in quantum computers.
This research is a very important milestone in the construction of quantum computing systems that are primarily based on semiconductor materials or nanocrystals.
