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.

Broadband infrared absorber based on a sputter deposited hydrogenated carbon multilayer enhancing MEMS-based CMOS thermopile performance.

Based on pulsed DC sputter deposition of hydrogenated carbon, an absorber optical coating with maximized broadband infrared absorptance is reported. Enhanced broadband (2.5-20 µm) infrared absorptance (>90) with reduced infrared reflection is achieved by combining a low-absorptance antireflective (hydrogenated carbon) overcoat with a broadband-absorptance carbon underlayer (nonhydrogenated).

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.

Miniaturised Infrared Spectrophotometer for Low Power Consumption Multi-Gas Sensing.

Concept, design and practical implementation of a miniaturized spectrophotometer, utilized as a mid-infrared-based multi gas sensor is described. The sensor covers an infrared absorption wavelength range of 2.9 to 4.

Simulation analysis and preparation of a high optical density laser protection filter.

High optical density (OD) filters have been widely used in space observation, optical detection, and laser protection. However, the lack of high OD value filters is restricting their application. This paper reports the formulation of a three-dimensional mesh model that can help predict the effects of pinhole defects, thickness error, and uniformity on the transmittance and OD value of optical filters.

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.

Low-cost hyper-spectral imaging system using a linear variable bandpass filter for agritech applications.

Hyperspectral imaging for agricultural applications provides a solution for non-destructive, large-area crop monitoring. However, current products are bulky and expensive due to complicated optics and electronics. A linear variable filter was developed for implementation into a prototype hyperspectral imaging camera that demonstrates good spectral performance between 450 and 900 nm.