Methods

||Quantum Theory

Atoms, electrons or the photons that make up light, are full of surprises. For instance, they can exist in more than one place at once or exist in a shared state, no matter what their physical separation. Classical theory still tends to prevail, in recent postulations that no information gain implies no disturbance or that disturbance leads to some form of information gain.

||Electromagnetic (EM) Simulations

The Raman Enhancement Factor (EF) is typically determined with EM simulations by using generalized Mie theory (GMT) and Finite Difference Time Domain techniques such as 2D-FDTD and 3D-FDTD. However, these techniques are computationally limited to simple geometric systems such two-nanoparticle clusters of perfect spheres.

||Light-emitting diode (LED)

LEDs naturally give off a bright blue light when electrons move through a semiconductor material. However, rare-earth-element phosphors help to better resemble sunlight. As an alternative, Si NPs under 5 nm may be added to the LED bulbs to soften the emitted light.

||Microscopy

Nanostructers may not be seen under the microscope since being smaller than the diffraction limit of light. Confocal microscopy is still a popular means of witnessing the effects of illuminating a sample with embedded nanostructures (e.g. cells, chemical dyes, plasmonic structures etc.). Stimulated emission depletion (STED) technology improves on confocal capabilities that achieves sub 30nm resolution. This is accomplished by deactivating fluorophores to enhance the imaging.

||Polariton Laser

Recently developed based on conventional semiconductor lasers. Excitons are formed when the electrons and electron holes are attracted to each other in a quantum well due to applied electric voltage. Polaritons result from strong light-matter coupling of these excitons in semiconductor micro-cavities. When excitons decay, photons are created. Cooled temperatures are required.

||Random Laser

A random laser works on an optical pump principal as opposed to  having mirrors as in conventional systems. Ordinary incoherent light is converted into ordered, coherent laser light, which is radially emitted into all directions. A predetermined emission pattern is achieved by optimizing the optical pump pattern.

||Regular Laser

Tweezer and levitation effects are possible with the forces produced by a self-focused laser beam.

||Wide-Field Temporal Focusing (WF-TeFo)

A two-photon pulse laser used for fast volumetric (3-D) imaging. Thin lateral “discs” of excitation light are created while retaining exceptional axial resolution. These 1-D “discs” are combined into 3-D images of sculpted light.

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Synthetic Structures

||Microcavity

Regulating the flow of energy is integral to electronics engineering. When it comes to light communication, several diode options are available (e.g. thin film). Another option includes gallery microcavities that may translate or “whisper” light in between doughnut shaped optical resonators (one with gain and the other with loss) on a silicon chip to different ports.

Second harmonic generation by micro-disks has recently come into realization. The breakthrough made it possible to use GaAs as a “whisper” gallery to strongly interact with the passing light and double its frequency. Energy and momentum are conserved in the frequency-doubling process through a fundamental constant and quasi-phase matching respectively.

||Crystal

A femtosecond pulsed laser creates nanostructured dots on glass. This information is encoded in 5D space: size, orientation and 3 normal directions of the nanostructure. The polarization of light passing through a 3 layer crystal with 5um separation can then be read by a combination of an optical microscope and a polarizer. The result is an ultra-high data capacity, thermal stability up to 1000 degC and practically an unlimited data lifetime.

In another application, optical lattice clocks loose one second every 300 million years which makes them three times as accurate as current atomic clocks.  Light is used to excite strontium atoms and the atomic vibration measurements are taken. An ion clock is also under development. Dependence on a single atoms reduces its relative stability, but the accuracy is deemed to be loosing only one second every few billion years.

Electrical switching may also be induced by a laser light source. Magnetite’s electronic structure breaks down into conducting and non-conducting regions in the first 1 trillionth of a second. The switch occurs between non-conducting and conducting states.

||Surface plasmon

Propagation of EM waves along a surface due to incident light has applications in electrical switching, solar cells, LEDs etc. Even though Au or Ag is typically required, polymer composites can also be engineered to sustain cheaper and more flexible devices.

||Plasmonic arrays

Repeatability of a structure allow for better engineered devices with better consistency. Pillars are popular due to the ease of synthesis, usually by standard MEMS techniques. LSPR with this structure is also possible at IR wavelengths in heavily silicon (Si) doped indium arsenide (InAs) microparticles. In other cases, ordered Au NPs can produce low-energy photons in the visible spectrum when energized with a beam of electrons.

Single molecule detection may also be possible with plasmonic arrays. An array of Au hills folded into a spherical NP shape promote local electromagnetic enhancement regions. The detection of a single thyroid cancer marker (Thyroglobulin, Tg) and bovine serum albumin (BSA) proteins was made possible with such NPs and with tracking the variation in surface plasmon resonance upon irradiation with 780nm wavelength excitation.

||Wave manipulation

Features smaller than a wavelength of light have astonishing properties. For example, plasmonic nanoparticles may aggregate to for a wave mixer. This means that it is possible to mix colors in a very general way. One can send beams of two different colors and get a third color for example.

at Open ND (TM)

We have shown plasmonic response of traditionally inactive TiO2 by nanofibrous structuring. We have used simulations, empirical calculations, formula constructs, near-field scanning microscopy etc. to demonstrate this new behaviour. The potential of our development is the possibility to use any material other than purely gold or silver in plasmonic devices.