Modern microelectronic semiconductors and integrated circuits provide remarkable computational and memory capabilities but lack the capability to interface with the physical world directly. MEMS (MicroElectroMechanical Systems) and the even smaller NEMS (Nano ElectroMechanical Systems) integrate sensors and actuators on microelectronic circuitry and enabling these products, awareness of the surroundings in the physical world, and allow them to perform physical tasks and send/receive inputs/outputs. Further,
Micro-Opto-Electro-Mechanical Systems (MOEMS) or optical microsystems are integrated devices or systems that interact with light through actuation or sensing at a micro- or millimeter scale. MOEMS merges MEMS with micro-optics as required for sensing and/or manipulating optical signals or light on a very small scale using integrated mechanical, optical, and electrical systems. Examples include digital light-projection devices and mini spectrometers, with applications such as projection systems, 3D printers, and instrumentation.
With the continuous reduction of device size, the MEMS field is gradually developing into the nano-electro-mechanical systems (NEMS) regime. When the size of the device is reduced to match the wavelength of light, a number of new types of micronano structures have emerged to combine with the field of nanophotonics. A new class of hybrid systems that couple optical, electrical and mechanical degrees of freedom in nanoscale devices is under development in laboratories worldwide. These nano-opto-electro-mechanical systems (NOEMS) offer unprecedented opportunities to control the flow of light in nanophotonic structures, at high speed and low power consumption. Drawing on conceptual and technological advances from the field of optomechanics, they also bear the potential for highly efficient, low-noise transducers between microwave and optical signals, in both the classical and the quantum domains.
The mechanical properties of nano structures are different from micro ones. It has been found in experiments that mechanical properties are changed as the size of the structures decreases in various materials such as metal materials, composite materials, polymer materials, and semiconductor materials. Compared with MEMS, NEMS are highly sensitive to small mass, displacements, and forces.
From the perspective of microscopic particles, the physical mechanism of NOEMS is essentially the interaction between photons, electrons, and phonons. The electro-optic effect between electrons and photons is enhanced by the control of phonons. The refractive index of a NOEMS device could be changed under an applied electric field due to the photoelastic effect caused by the inverse piezoelectric effect of the atomic lattices, which leads to an enhanced electro-optic effect.
By exploiting NOEMS concepts and technologies, high speed and low-power consumption switches, high-efficiency microwave-optical conversion devices, and multiple quantum information processing functions can be implemented through on-chip integration.
Over the last few decades, people have been able to manipulate single quantum in different ways. And carrier of single quantum can be single photon, charge, and phonon. The three types of nanoparticles defined from a quantum perspective constitute a hybrid NOEMS system from a macroscopic perspective, corresponding to the three aspects of optics, electronics, and mechanics, respectively. On the contrary, with the rapid development of quantum technology in recent years, NOEMS has gradually realized the control of nanoparticles
With the rapid development of quantum communication, quantum calculation and high-precision detection, quantum light source plays an increasingly important role in the researches of quantum information technologies. The ideal single-photon source needs to meet the following conditions: (1) Emitting a single photon at any time, so that the probability of emiting a single photon is 1; (2) once the photons are emitted, the efficiency of each photon in the ideal quantum channel is uniform; and (3) each photon emitted should be indistinguishable and homogenous.
The newest single-photon source based on quantum dots researched internationally, with higher performance and gradually approaching the ideal single-photon source, has also opened up a new technological path to integrated single-photon source. With the single-photon source that can be integrated on a chip, we can get a variety of applications by embedding the single-photon emitters in the photon circuits.
Photon routing using reconfigurable integrated circuits is a key function of quantum information processing. Single -photon router is based on two adjustable waveguides whose spacing can be changed by the external voltage
Quantum photonic integrated circuits are promising new type of semiconductor technology, where single-photon emitters are embedded and the evolution of quantum states of the emitted photons from those emitters are adopted to manipulate information. Good quality single-photon emitters are usually embedded in nanocavities, however, energy mismatch between the cavities and the emitters is usually inevitable, which sets challenges to the implementation of circuits to simultaneously manipulate single photons from remote emitters. However, the inevitable energy mismatch between remote cavities and points, as well as the difficulty of coupling with the waveguide network, hinders the implementation of circuits that simultaneously manipulate single photon generated from remote sources. So in order to obtain high purity and coherent single photons from quantum dots, we need spectral filtering to select single exciton transitions. Wavelength-tunable filter on a chip integrated with a single photon source can also be implemented using nanomechanical motion. In addition, multiple tunable quantum dot sources are integrated in the photonic circuit. The electrically tunable single photon source is combined with the mechanically reconfigurable photonic crystal element. This platform can be applied to multi-cavity quantum electrodynamics nodes in the near future.