Nada A. O'Brien

Large area electrochromics for architectural applications

Abstract Electrochromic (EC) devices suitable for large area architectural applications require a minimum acceptable performance in depth of color, switching time, chromatism and durability to be viable. In this paper we discuss these minimum needs and present performance data on various devices that meet or exceed most of these requirements with neutral coloration and depth of color > 10:1. These devices have demonstrated repeatable performance for > 20 000 cycles.

Qualitative and quantitative pharmaceutical analysis with a novel hand-held miniature near infrared spectrometer

Although miniaturisation of vibrational spectrometers began approximately a decade ago, only within the last couple of years have real hand-held Raman, infrared and near infrared (NIR) scanning spectrometers became commercially available. On the customer end the development of portable instrumentation was driven by the request for more flexibility of on-site measurements and on the manufacturer side it was supported by the potential and advantages of micro-electromechanical systems (MEMS) production and the implementation of new technologies. With reference to NIR spectroscopy the expectations for a real hand-held system (<100 g) have been recently realised by a pocket-sized spectrometer with a linear variable filter technology (LVF) as monochromator principle and the additional benefit of significantly reduced costs compared to other portable systems. For a real breakthrough and impact of this instrument, however, it had to be demonstrated that competitive analytical results can be achieved. In this respect, the present communication has put to test the performance of this micro-NIR system with reference to selected qualitative and quantitative pharmaceutical applications.

Miniature Near-Infrared (NIR) Spectrometer Engine For Handheld Applications

While substantial progress has been made recently towards the miniaturization of Raman, mid-infrared (IR), and near-infrared (NIR) spectrometers, there remains continued interest from end-users and product developers in pushing the technology envelope toward even smaller and lower cost analyzers. The potential of these instruments to revolutionize on-site and on-line applications can only be realized if the reduction in size does not compromise performance of the spectrometer beyond the practical need of a given application. In this paper, the working principle of a novel, extremely miniaturized NIR spectrometer will be presented. The ultra-compact spectrometer relies on thin-film linear variable filter (LVF) technology for the light dispersing element. We will also report on an environmental study whereby the contamination of soil by oil is determined quantitatively in the range of 0-12% by weight of oil contamination. The achieved analytical results will be discussed in terms of the instruments competitiveness and suitability for on-site and in-the-field measurements.

Ultra-low stress coating process: an enabling technology for extreme performance thin film interference filters

We present a record-breaking performance of an ultra-low stress 8-skip-0 100GHz thin film filter enabled by a new coating process. The coating has 17 cavities, over 400 quarter-wave layers, and a physical thickness of 94 micrometers.

Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe

The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground- and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at Palomar and in the laboratory at JPL, and Hokkaido University. Manufacturing technologies for devices covering wavelength ranges from the optical to the mid-infrared, have been maturing quickly. We will review the current status of technology developments supported by NASA in the USA (Jet Propulsion Laboratory-California Institute of Technology, University of Arizona, JDSU and BEAMCo), Europe (University of Li`ege, Observatoire de Paris- Meudon, University of Uppsala) and Japan (Hokkaido University, and Photonics Lattice Inc.), using liquid crystal polymers, subwavelength gratings, and photonics crystals, respectively. We will then browse concrete perspectives for the use of the VVC on upcoming ground-based facilities with or without (extreme) adaptive optics, extremely large ground-based telescopes, and space-based internal coronagraphs.

Pocket-Size Near-Infrared Spectrometer for Narcotic Materials Identification

While significant progress has been made towards the miniaturization of Raman, mid-infrared (IR), and near-infrared (NIR) spectrometers for homeland security and law enforcement applications, there remains continued interest in pushing the technology envelope for smaller, lower cost, and easier to use analyzers. In this paper, we report on the use of the MicroNIR Spectrometer, an ultra-compact, handheld near infrared (NIR) spectrometer, the, that weighs less than 60 grams and measures < 50mm in diameter for the classification of 140 different substances most of which are controlled substances (such as cocaine, heroin, oxycodone, diazepam), as well as synthetic cathinones (also known as bath salts), and synthetic cannabinoids. A library of the materials was created from a master MicroNIR spectrometer. A set of 25 unknown samples were then identified with three other MicroNIRs showing: 1) the ability to correctly identify the unknown with a very low rate of misidentification, and 2) the ability to use the same library with multiple instruments. In addition, we have shown that through the use of innovative chemometric algorithms, we were able to identify the individual compounds that make up an unknown mixture based on the spectral library of the individual compounds only. The small size of the spectrometer is enabled through the use of high-performance linear variable filter (LVF) technology.

Miniature near-infrared spectrometer for point-of-use chemical analysis

Point-of-use chemical analysis holds tremendous promise for a number of industries, including agriculture, recycling, pharmaceuticals and homeland security. Near infrared (NIR) spectroscopy is an excellent candidate for these applications, with minimal sample preparation for real-time decision-making. We will detail the development of a golf ball-sized NIR spectrometer developed specifically for this purpose. The instrument is based upon a thin-film dispersive element that is very stable over time and temperature, with less than 2 nm change expected over the operating temperature range and lifetime of the instrument. This filter is coupled with an uncooled InGaAs detector array in a small, rugged, environmentally stable optical bench ideally suited to unpredictable environments. The resulting instrument weighs less than 60 grams, includes onboard illumination and collection optics for diffuse reflectance applications in the 900-1700 nm wavelength range, and is USB-powered. It can be driven in the field by a laptop, tablet or even a smartphone. The software design includes the potential for both on-board and cloud-based storage, analysis and decision-making. The key attributes of the instrument and the underlying design tradeoffs will be discussed, focusing on miniaturization, ruggedization, power consumption and cost. The optical performance of the instrument, as well as its fit-for purpose will be detailed. Finally, we will show that our manufacturing process has enabled us to build instruments with excellent unit-to-unit reproducibility. We will show that this is a key enabler for instrumentindependent chemical analysis models, a requirement for mass point-of-use deployment.

Vector vortex coronagraph: first results in the visible

We report the status of JPL and JDSU ongoing technological developments and contrast results of the vector vortex coronagraph (VVC) made out of liquid crystal polymers (LCP). The first topological charge 4 VVC was tested on the high contrast imaging testbed (HCIT) around 800 nm, under vacuum and with active wavefront control (32x32 Xinetics deformable mirror). We measured the inner working angle or IWA (50% off-axis transmission) at ~ 1.8λ/d. A one-sided dark hole ranging from 3λ/d to 10λ/d was created in polarized light, showing a mean contrast of ~ 2 × 10-7 over a 10% bandwidth. This contrast was maintained very close in (3 λ/d) in a reduced 2% bandwidth. These tests begin to demonstrate the potential of the LCP technology in the most demanding application of a space-based telescope dedicated to extrasolar planet characterization. The main limitations were identified as coming from incoherent sources such as multiple reflections, and residual chromaticity. A second generation of improved masks tackling these issues is being manufactured and will be tested on the HCIT in the coming months.

An electrochromic variable optical attenuator (ECVOA)

New electronically controlled infrared variable optical attenuators based on thin film electrochromic technology are presented. Initial ECVOA prototypes have up to 15 dB attenuation range, 0.5 dB insertion loss, and a switching rate of 5 dB/sec. These devices are broadband, continuously variable, compact and polarization insensitive.

Inorganic Reflective Achromatic Quarter-Waveplate for Optical Pick-up Applications

This paper discusses the design, fabrication and application of a quarter-waveplate (QWP) element to address reliability, retardance achromaticity, small wavefront distortion and low-cost aspects of polarization controlling components in high definition, three-channel optical-pickup systems. The retarder is an all-inorganic reflective QWP that provides achromatic 90° retardance for the three laser wavelength bands. These 200-mm wafer scale fabrication parts show a retardance uniformity of about 3%. The surface distortion of these thin-film coated components has been measured to be less than 0.01 waves RMS over 4.5 mm square aperture at 633 nm wavelength. These all-inorganic reflective QWPs developed by JDSU are flexible in design, durable and highly reliable under high light flux exposure and adverse environmental conditions. Several prototype parts have been tested for damp-heat, thermal cycling, low and high temperature storage and the measured 0.5% retardance variations after 2300 h is comparable to the errors of retardance metrology.