Diamond Integrated Quantum Photonics: A Review

Integrated quantum photonics devices in diamond have tremendous potential for many quantum applications, including long-distance quantum communication, quantum information processing, and quantum sensing. These devices benefit from diamond's combination of exceptional thermal, optical, and mechanical properties. Its wide electronic bandgap makes diamond an ideal host for a variety of optical active spin qubits that are key building blocks for quantum technologies. In landmark experiments, diamond spin qubits have enabled demonstrations of remote entanglement, memory-enhanced quantum communication, and multi-qubit spin registers with fault-tolerant quantum error correction, leading to the realization of multinode quantum networks. These advancements put diamond at the forefront of solid-state material platforms for quantum information processing. Recent developments in diamond nanofabrication techniques provide a promising route to further scaling of these landmark experiments towards real-life quantum technologies. In this paper, we focus on the recent progress in creating integrated diamond quantum photonic devices, with particular emphasis on spin-photon interfaces, cavity optomechanical devices, and spin-phonon transduction. Finally, we discuss prospects and remaining challenges for the use of diamond in scalable quantum technologies.Comment: 31 pages, 8 figure

Responsive liquid crystal polymer rods

In this dissertation I report on the successful fabrication of anisotropic liquid crystal polymer rods. These polymer rods demonstrated re-orientation by an applied external field. The polymer rods, 200 nm in diameter and a maximum of 60 mum in length, were produced by a template synthesis technique. A reactive liquid crystal monomer was filled into porous Anopore membranes which were used as a confining media. The liquid crystal monomer was polymerized by UV light while the liquid crystal remained in the nematic temperature range. The polymerization process permanently freezes the orientational order of the confined liquid crystal molecules, producing rods that are temperature independent after curing. The curing is kept in the nematic range to ensure proper orientational alignment in the pore of the membrane, where the responsive nature of the rods can be tailored by temperature, external fields, and/or surface treatments. The rods were suspended in low viscosity silicone oil and injected into indium tin oxide coated glass cells.;Both DC and AC electric fields were applied to the electro-optical glass cells, resulting in different types of rod movement. Switching times (time to change orientation from horizontal to vertical) has been observed to be as fast as 0.1 seconds and the threshold voltage has been as low as 5 volts. The switching times of the rods are mainly driven by the strength of the applied field and the molecular orientation of the rods. A model was used to describe the best case scenario of the rod structures and outlines that faster switching times are possible. Translational movement (moving vertical with the rod staying in the horizontal position) was also noted with the DC applied field. AC fields give different types of movement including rotational, vibrating, and swimming motions. The average rotational speed was found to vary linearly with the applied field strength, where the fastest speeds were at the highest field strength. Also, responsive rods were noted to move and push unresponsive rods in and out of the viewing area. The responsive rods are technologically important for possible electro-rheological fluids, magneto-rheological fluids, and components in microfluidic devices

Electro-active liquid crystal dispersed composites

In this thesis, the movement of anisotropic liquid crystal polymer rods in dispersion fluids of silicon oils was investigated. The rods demonstrated movement by an applied external AC field. The polymer rods used were 200 nm in diameter and 60 mum in length produced using the template synthesis technique originally adopted by Shafran (2008). A reactive liquid crystal monomer was polymerized by ultraviolet light while the liquid crystal remained in the nematic temperature range. This curing permanently fixes the liquid crystal molecules, producing polymer rods independent of temperature. The rods were dispersed in silicon oils of viscosities 4.7, 9.2, and 99 cP, and injected into indium tin oxide coated glass cells.;An AC electric field was applied to the glass cells, resulting in multiple types of movement from the rods. In the silicon oil of viscosity 4.7 cP, the rod motions that were observed was spinning about a central point or large circular movements. In silicon oil of viscosity 9.2 cP, the motions that were observed was either wagging or flexing of the rods. Also, in the silicon oil of viscosity 99 cP, the motions that were observed were large circular movements and wagging. The ability of the polymer rods to respond in highly viscous dispersion fluids is technologically important for possible applications in active micromixers, morphing wings, and LC displays

Roadmap for optical tweezers

Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects, ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in the life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nano-particle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration.journal articl

Simultaneous measurement for material parameters using self-mixing interferometry

Material related parameters such as Young’s modulus and internal friction are important for mechanical and material engineering. These parameters play key roles in the material performances. It has been a great interest to measure the value of these parameters. Traditional methods including tensile test, flexure test, and others are destructive methods often cause damages to specimen and have low accuracy. In recent years, the impulse excitation technique (IET), a non-destructive technique to determine Young’s modulus and internal friction of the material has attracted great attention. The detection system used for IET is normally microphone, accelerometer and so on. Selfmixing interferometry (SMI), an emerging sensing technique, which is non-destructive, non-contact, compact structure, and low-cost has been developed for high accuracy sensing applications, such as displacement, velocity and distance measurement and so on is suitable for the material related parameters measurement. A normal SMI system consists of a laser diode (LD) and a target to form the external cavity of the LD. When a portion of the light is reflected or backscattered to the laser cavity, leading to a modulated laser power of LD. This modulated laser power is referred as SMI signal, which carries the information of vibration of the target. In this thesis, a measurement method combining IET with SMI for material related parameters measurement is proposed. By applying wavelet transform onto the SMI signal, both resonant frequency and damping factor of the specimen vibration can be retrieved at the same time. Therefore, both Young’s modulus and internal friction of the specimen can be calculated simultaneously. The optical fibre is introduced to the system. With the installation of the optical fibre, the flexibility of the measurement is greatly improved. The measurement results show the feasibility for simultaneous measurement of material related parameters. A graphical user interface is designed to improve the user experience for the measurement

Quantum magnonics: when magnon spintronics meets quantum information science

Spintronics and quantum information science are two promising candidates for innovating information processing technologies. The combination of these two fields enables us to build solid-state platforms for studying quantum phenomena and for realizing multi-functional quantum tasks. For a long time, however, the intersection of these two fields was limited. This situation has changed significantly over the last few years because of the remarkable progress in coding and processing information using magnons. On the other hand, significant advances in understanding the entanglement of quasi-particles and in designing high-quality qubits and photonic cavities for quantum information processing provide physical platforms to integrate magnons with quantum systems. From these endeavours, the highly interdisciplinary field of quantum magnonics emerges, which combines spintronics, quantum optics and quantum information science.Here, we give an overview of the recent developments concerning the quantum states of magnons and their hybridization with mature quantum platforms. First, we review the basic concepts of magnons and quantum entanglement and discuss the generation and manipulation of quantum states of magnons, such as single-magnon states, squeezed states and quantum many-body states including Bose-Einstein condensation and the resulting spin superfluidity. We discuss how magnonic systems can be integrated and entangled with quantum platforms including cavity photons, superconducting qubits, nitrogen-vacancy centers, and phonons for coherent information transfer and collaborative information processing. The implications of these hybrid quantum systems for non-Hermitian physics and parity-time symmetry are highlighted, together with applications in quantum memories and high-precision measurements. Finally, we present an outlook on the opportunities in quantum magnonics.Comment: 93 pages, 35 figures, Physics Reports (in press