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A little more than two decades after the introduction of the first microcavity plasma devices, a growing body of commercial products based on the remarkable properties of these low-temperature, atmospheric plasmas is now available. Following a brief review of early microplasma lamp development, this article describes microplasma-based devices and systems currently being manufactured for applications in photolithography, photopatterning, and other nanofabrication processes, such as atomic layer deposition, spectroscopic identification and analysis of materials (including wide bandgap crystals), the disinfection of drinking water in off-grid communities, deactivating COVID-19 and other pathogens in air and on surfaces in public spaces, and vacuum ultraviolet lamps for driving atomic clocks. The microplasma-based treatment of otitis media in the human ear will also be discussed.

The enduring contributions of low temperature plasmas to both technology and science are largely a result of the atomic, molecular, and electromagnetic (EM) products they generate efficiently such as electrons, ions, excited species, and photons. Among these, the production of light has arguably had the greatest commercial impact for more than a century, and plasma sources emitting photons over the portion of the EM spectrum extending from the microwave to soft x-ray regions are currently the workhorses of general lighting (outdoor and indoor), photolithography for micro- and nano-fabrication of electronic devices, disinfection, frequency standards (atomic clocks), lasers, and a host of other photonic applications. In several regions of the EM spectrum, plasma sources have no peer, and this article is devoted to an overview of the physics of several selected plasma light sources, with emphasis on thermal arc and fluorescent lamps and the more recently-developed microcavity plasma lamps in the visible and ultraviolet/vacuum ultraviolet regions. We also briefly review the physics of plasma-based metamaterials and plasma photonic crystals in which low temperature plasma tunes the EM properties of filters, resonators, mirrors, and other components in the microwave, mm, and sub-mm wavelength regions.

Microplasmas are low-temperature plasmas that feature microscale dimensions and a unique high-energy-density and a nonequilibrium reactive environment, which makes them promising for the fabrication of advanced nanomaterials and devices for diverse applications. Here, recent microplasma applications are examined, spanning from high-throughput, printing-technology-compatible synthesis of nanocrystalline particles of common materials types, to water purification and optoelectronic devices. Microplasmas combined with gaseous and/or liquid media at low temperatures and atmospheric pressure open new ways to form advanced functional materials and devices. Specific examples include gas-phase, substrate-free, plasma-liquid, and surface-supported synthesis of metallic, semiconducting, metal oxide, and carbon-based nanomaterials. Representative applications of microplasmas of particular importance to materials science and technology include light sources for multipurpose, efficient VUV/UV light sources for photochemical materials processing and spectroscopic materials analysis, surface disinfection, water purification, active electromagnetic devices based on artificial microplasma optical materials, and other devices and systems including the plasma transistor. The current limitations and future opportunities for microplasma applications in materials related fields are highlighted.

Spectroscopic studies of XeF and KrF electronically excited molecules in electron beam produced rare gas-halogen plasmas have been conducted. Experimental evidence indicates that the 248 and 275 nm emission bands of the KrF* complex originate from separate upper states. These continua are assigned to CtoX and BtoA transitions, respectively, of electronically excited KrF. Due to similarities in structure and emission spectra, an analogous situation is believed to exist in XeF. (Author)

This invention relates to a technique for lasing a gas in a gas lasing device to obtain stimulated light emission at a desired wavelength by bottlenecking the high gain transitions in the gas so that certain low gain transitions which will yield the desired wavelength are now able to oscillate. This technique comprises the steps of optimizing the mirror transmission for the desired light frequency, and pumping the laser gas with a pulse whose width is much longer than that required to bottleneck the high gain transitions. This technique may be utilized with both molecular and atomic gases., Supersedes PAT-APPL-199 895-80, AD-D008 000.

This patent discloses an optically pumped laser which is operative by photolysis of a rare gas (RG)-halogen atom (X) compound (RGX2) which creates lasing from the RGX* molecule the RGX* molecule being diatomic. This type of laser is gaseous but a solid fuel is used to supply the gas; therefore the system is self contained., Supersedes PAT-APPL-033 298-79, AD-D006 088.

A high-power gas laser pumped by an intense, pulsed, space charge-and-current-neutralized ion beam is described. A high-pressure gas in the laser cavity is ionized by an ion beam. Atomic processes occur which result in a population inversion for the excited states of the gas. Coherent radiation is then emitted by the excited gas atoms in the inverted state. The light is amplified as it traverses the gas. Multiple traversal can be obtained by using an optical cavity comprising mirrors which reflect the light into the excited gas so that the light can be further amplified with each pass through the cavity. Extraction of light energy is done by using a partially transmitting mirror as part of the optical cavity. (Author), Supersedes PAT-APPL-936 158-78, AD-D005 380.