Amorphous dielectric optical coatings deposited by plasma ion-assisted electron beam evaporation for gravitational wave detectors.

Coating thermal noise (CTN) in amorphous coatings is a drawback hindering their application in precision experiments such as gravitational wave detectors (GWDs). Mirrors for GWDs are Bragg's reflectors consisting of a bilayer-based stack of high- and low-refractive-index materials showing high reflectivity and low CTN. In this paper, we report the characterization of morphological, structural, optical, and mechanical properties of high-index materials such as scandium sesquioxide and hafnium dioxide and a low-index material such as magnesium fluoride deposited by plasma ion-assisted electron beam evaporation.

Breath emulator for simulation and modelling of expired tidal breath carbon dioxide characteristics.

Background: In this work we describe a breath emulator system, used to simulate temporal characteristics of exhaled carbon dioxide (CO) concentration waveform versus time simulating how much CO2 is present at each phase of the human lung respiratory process. The system provides a method for testing capnometers incorporating fast response non-dispersive infrared (NDIR) CO gas sensing devices - in a clinical setting, capnography devices assess ventilation which is the CO movement in and out of the lungs. A mathematical model describing the waveform of the expired CO characteristic and influence of CO gas sensor noise factors and speed of response is presented and compared with measured and emulated data.

Durable infrared optical coatings based on pulsed DC-sputtering of hydrogenated amorphous carbon (a-C:H).

Optical properties of low-temperature pulsed DC-sputter deposited ($ {\le} {70° {\rm C}}$≤70°C) hydrogenated carbon are presented. Increasing hydrogen incorporation into the sputter deposited carbon significantly decreases infrared optical absorption due to a decrease in deep absorptive states associated with dangling bonds. Hydrogen flow is optimized (hydrogen flow 3 sccm), achieving the best compromise between increased infrared transmittance and hardness for durable coating performance.

Polariton-mediated energy transfer between organic dyes in a strongly coupled optical microcavity.

Strongly coupled optical microcavities containing different exciton states permit the creation of hybrid-polariton modes that can be described in terms of a linear admixture of cavity-photon and the constituent excitons. Such hybrid states have been predicted to have optical properties that are different from their constituent parts, making them a test bed for the exploration of light-matter coupling. Here, we use strong coupling in an optical microcavity to mix the electronic transitions of two J-aggregated molecular dyes and use both non-resonant photoluminescence emission and photoluminescence excitation spectroscopy to show that hybrid-polariton states act as an efficient and ultrafast energy-transfer pathway between the two exciton states.