In order to enable optical systems to operate with a high degree of compactness and reliability it is necessary to combine large number of optical functions in small monolithic structures. A development, somewhat reminiscent of that that took place in Integrated Electronics, is now beginning to take place in optics. The initial challenge in this emerging field, known appropriately as "Integrated Optics", is to demonstrate the possibility of performing basic optical functions such as light generation, coupling, modulation, and guiding in Integrated Optical configurations. The talk will review the main theoretical and experimental developments to date in Integrated Optics. Specific topics to be discussed include: Material considerations, guiding mechanisms, modulation, coupling and mode losses. The fabrication and applications of periodic thin film structures will be discussed.

Integrated optics

Water purification using magnetic assistance: a review.

In an embodiment, a system includes one or one or more reservoirs responsive to control circuitry for receiving target(s) associated with one or more blood or lymph vessel of a subject. The system includes one or more first energy source associated with the one or more reservoirs for providing energy to elicit image response(s) associated with the target(s). The system includes one or more sensors associated with the one or more reservoirs for capturing the image response(s). Control circuitry is provided and coupled to the sensors for at least partially identifying the target(s) based at least partially on the captured image response(s) during an expected transit time of the target(s) through a detection area. Attachment unit(s) responsive to the control circuitry are provided for attaching the one or more reservoirs to the blood or lymph vessel.

Vasculature and lymphatic system imaging and ablation associated with a reservoir

Direct and indirect influence on microorganisms of non-thermal atmospheric-pressure DBD in air is compared in terms of bacterial inactivation rates. It is demonstrated that direct influence of the plasma, where charged particles contact bacteria directly, produces inactivation much faster than the indirect treatment, where plasma afterglow is delivered to the bacteria with a gas flow through the plasma region. This leads to an important conclusion that the effect of charged particles on plasma plays the essential role in interaction with living organisms, although synergy with longer living active molecules and atoms as well as UV radiation generated in plasma and at the surface of tissues may also play a role in inactivation.

Comparison of Direct and Indirect Effects of Non‐Thermal Atmospheric‐Pressure Plasma on Bacteria

Pulsed light (PL) is a technique to decontaminate surfaces by killing microorganisms using pulses of an intense broad spectrum, rich in UV-C light. The present review is focused on the application of PL for food decontamination. It revises the mechanism of microbial inactivation (UV-C as the most important part of the spectrum, photothermal and photochemical mechanisms, inactivation curve, peak power dependence, and photoreactivation), the factors affecting its efficacy, the advantages and problems associated with PL treatment, and results obtained in vitro. Examples of applications to foods are given, including microbial inactivation, and effects on food matrices.

Pulsed light for food decontamination: a review

The experimental results on the development of a decontamination process that uses ultraviolet light and chemical photosensitizer for disinfecting surfaces and solutions are reported. Reduction in the microbial viability as a function of applied UV fluence is presented for the inactivation of Bacillus subtilis spores. Results obtained with aqueous solutions and with surfaces indicate that pulsed UV light is more effective than continuous UV light. Nearly three orders of magnitude of enhanced inactivation have been achieved with the photosensitized UV process on surfaces.

A comparison of pulsed and continuous ultraviolet light sources for the decontamination of surfaces

A method of deactivating chemical contaminants and biological agents from a target surface (22) by aerosol spraying (24) the target surface (22) with an electrostatically charged photosensitizer solution (20), and then illuminating the surface with ultraviolet light (26).

Method and apparatus for photosensitized ultraviolet decontamination of surfaces and aerosol clouds

Considerations for choice of a kinetic fig. of merit in process radiation chemistry for waste treatment.

High-voltage-rated solid-state switches such as insulated-gate bipolar transistors (IGBTs) are commercially available up to 6.5 kV. Such voltage ratings are attractive for pulsed power and high-voltage switch-mode converter applications. However, as the IGBT voltage ratings increase, the rate of current rise and fall are generally reduced. This tradeoff is difficult to avoid as IGBTs must maintain a low resistance in the epitaxial or drift region layer. For high-voltage-rated IGBTs with thick drift regions to support the reverse voltage, the required high carrier concentrations are injected at turn on and removed at turn off, which slows the switching speed. An option for faster switching is to series multiple, lower voltage-rated IGBTs. An IGBT-stack prototype with six, 1200 V rated IGBTs in series has been experimentally tested. The six-series IGBT stack consists of individual, optically isolated, gate drivers and aluminum cooling plates for forced air cooling which results in a compact package. Each IGBT is overvoltage protected by transient voltage suppressors. The turn-on current rise time of the six-series IGBT stack and a single 6.5 kV rated IGBT has been experimentally measured in a pulsed resistive-load, capacitor discharge circuit. The IGBT stack has also been compared to two IGBT modules in series, each rated at 3.3 kV, in a boost circuit application switching at 9 kHz and producing an output of 5 kV. The six-series IGBT stack results in improved turn-on switching speed, and significantly higher power boost converter efficiency due to a reduced current tail during turn off. The experimental test parameters and the results of the comparison tests are discussed in the following paper

Analysis and Comparison of a Fast Turn-On Series IGBT Stack and High-Voltage-Rated Commercial IGBTS

Pulsed electric field (PEF) disinfection is a promising technology for the nonthermal disinfection of water. Magnetic pulse compressors due to their high repetition rates and lifetimes, appear to be a promising alternative to the existing pulse forming circuits used for sterilization applications. The application of these systems for the purification of water has yet to be explored. The use of the short duration electrical pulses from the magnetic pulse compressor for inactivation of spores, bacteria (Escherichia coli) and viruses in drinking water is being investigated at the University of Missouri, Columbia. The test cell designed herein allows flowing tests for pulsewidths of 130-500 ns. The coupling of the magnetic modulator with the test cell and the inactivation protocols that aim at effective inactivation under optimal conditions are discussed. A 4 log reduction was seen for (Escherichia coli) E. coli at field strengths of 110 kV/cm and 70 pps, with a total energy consumption of 40 J/cm3. A comparative study of different parameters, e.g., pulsewidth, electrode gap, frequency, and electric field, which effect the microbial inactivation are also presented

Randy D. Curry

Papers

A comparison of pulsed and continuous ultraviolet light sources for the decontamination of surfaces

Method and apparatus for photosensitized ultraviolet decontamination of surfaces and aerosol clouds

Considerations for choice of a kinetic fig. of merit in process radiation chemistry for waste treatment.

Analysis and Comparison of a Fast Turn-On Series IGBT Stack and High-Voltage-Rated Commercial IGBTS

Microbial Inactivation in Water Using Pulsed Electric Fields and Magnetic Pulse Compressor Technology