Astronomers have confirmed more than 5,000 exoplanets orbiting distant stars. There are a few aspects that are needed to characterize an exoplanet. One is the size of the planet, and the other is the mass of the planet.

Space-based missions, such as the Transiting Exoplanet Survey Satellite (TESS) launched in 2018, find exoplanets through events called transits, where a planet periodically blocks part of the light from its host star. These space-based missions do the precision photometry that is used to derive both the size of the planet - how big it is physically, the planet's diameter - and how far away from the star it is. TESS finds the most promising exoplanets orbiting our nearest and brightest stars, Earth-sized and super-Earth-sized exoplanets which are no larger than twice the size of Earth.

Until recently, many ground-based radial velocity measurements were performed with the High-Resolution Echelle Spectrometer (HIRES), located at the W.M. Keck Observatory (WKMO) on the summit of 13,796-ft Mauna Kea in Hawaii. HIRESs precision measurements can spot stars moving back and forth or wobbling, at a speed of about 200 cm/second.

Since its inception in 1959, SSL has participated in over 50 NASA space science missions, including the Apollo, Mars, Discovery, and Explorer programs, as well as many international space missions, said Kodi Rider, project manager of Keck Planet Finder at UC Berkeley Space Sciences Lab. KPF is focused to not only find smaller rocky planets, but ones in the habitable zones of their stars. Its precision enables unprecedented measurements of the masses, orbits, and compositions of smaller planets.

Thermal Stability
KPF was designed from the ground up to track the spectral fingerprints of stars to better than one part-per-billion precision. This scale of measurement represents a significant technological challenge and required every layer of the KPF system to be optimized to maximize performance...

Cilia, small, slender, hair-like structures present on the surface of all mammalian cells, play a major role in locomotion and are involved in mechanoreception. Ciliary motion in the upper airway is the primary mechanism by which the body transports foreign particulates out of the respiratory system to maintain proper respiratory function.

Ciliary motion plays a critical role in the overall respiratory health of the upper airway. Cilia beat at a native frequency, and in a synchronized pattern, to continuously transport foreign particulate trapped in a layer of mucous out of the upper airway.

The ciliary beating frequency (CBF) is often disrupted with the onset of disease as well as other conditions, such as changes in temperature or in response to drug administration. Disruption of ciliary motion can lead to severe respiratory diseases and compromised respiratory function.

Measuring CBF is a technical challenge and difficult to perform in vivo. Current imaging of cilia motion relies on microscopy and high-speed cameras which cannot be easily adapted to in vivo imaging.

Phase-contrast microscopy (PCM) is the standard for measuring CBF but has limitations. PCM does not permit appreciation of how CBF varies across the complex landscape of the nasal vault and sinus tissues. Additionally, optical coherence tomography (OCT) has proven to be a powerful imaging modality capable of visualization of ciliary activity, but its field of view is limited.

Spectrally encoded interferometric microscopy
A team of scientists and engineers at the Chen F-OCT Group, part of the Beckman Laser Institute of the Department of Biomedical Engineering at the University of California, Irvine (UCI), have designed a system capable of overcoming these limitations.
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Previously, the group developed a phase resolved Doppler optical coherence tomography (PR-D-OCT) system that was able to obtain lateral cross-sectional images of cilia and cilia movement in real-time. The inventors realized the need to observe the surface dynamics of cilia over time and spatially, so they developed a spectrally encoded interferometric microscopy (SEIM) system with PR-D technology. As a result, fast, high-resolution en face images of human CBF can be captured and processed in real-time. Additionally, the integration of PR-D-OCT with PR-D-SEIM provides a multidimensional view of cilia.
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SEIM has emerged as a high-speed, high-resolution methodology, allowing for visualization of both temporal and spatial ciliary motion patterns across the surface of upper airway tissues, as well as propagation of metachronal wave, says Zhikai Zhu, Ph.D. candidate with the Chen F-OCT Group. SEIM can detect displacement on the nanometer scale at a kilohertz frame rate..
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When coupled with a wavelength-swept laser and a spectral disperser, SEIM can image tissue en face, Zhu explains. SEIM uses a phase-resolved Doppler (PR-D) algorithm to measure and map the CBF within an en face region, providing insight into the changes in CBF across tissue surfaces.

Need for vibration isolation
Since we are imaging cilia tissue that is in motion, we need a stable environment to produce reliable images, Zhu continues. Without vibration isolation, reliable imaging from our SEIM system is sporadic. Our lab is adjacent to a heavy foot traffic area, creating vibrations that affect our signals, Zhu adds. Our need to isolate these ambient vibrations is critical.
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The F-OCT Laboratory selected Negative-Stiffness vibration isolation for its SEIM system. Introduced in the mid-1990s by Minus K Technology, Negative-Stiffness vibration isolation has been widely accepted for vibration-critical applications, largely because of its ability to effectively isolate lower frequencies, both vertically and horizontally.