Researchers at NASA’s Marshall Space Flight Center have developed a low-cost optical element designed specifically for neutron optics applications. The technology operates as a reflective lens—similar to proven grazing incidence optics used for x-ray imaging—and improves neutron imaging resolution for applications using low-energy (< 1 electron volt) neutrons. Capable of broadening narrow neutron beam sources or focusing diffused ones, the optical component can target a beam on a specific area instead of bathing an object, reducing the radiation dosages typically employed in neutron tomography for clinical and security applications. The proprietary electroformed nickel replication process used to manufacture these components in volume can also be employed to mass produce neutron waveguides.

Innovators at NASA’s Marshall Space Flight Center have patented a method for a ring-laser gyroscope (RLG) that incorporates dispersive elements to the optical path in order to improve sensitivity at low rotation rates. Conventional RLGs suffer from a dead-band in their response at low rotation rates. Current techniques to eliminate the dead-band introduce bias drift, increase gyroscope size, and are costly, complicated, and/or cumbersome to implement. The Marshall innovation modifies an existing laser gyroscope by inserting at least one dispersive element into the RLG's optical path. The absorption characteristics of the element reduce the relative dead-band, while the normal dispersion increases the sensitivity of the gyroscope. The technology requires no moving parts or external electromagnetic fields, and it does not increase the size of the RLG or substantially increase its cost. Resulting RLGs are more sensitive than conventional RLGs of the same size and could potentially use less power. Because RLG sensitivity is proportional to system size, the dispersion enhanced RLG can be substantially smaller than a conventional RLG while achieving the same or better sensitivity.

Researchers at NASA’s Marshall Space Flight Center have patented a phase sensor for aligning segmented telescope mirrors that increases precision measurements while maintaining alignment, even in the presence of atmospheric turbulence. Marshall’s design is based on an achromatic shearing interferometer, is compatible with many mature interferometry techniques, and can be used with a broadband or extended source. Sensor optics include a ruled diffraction grating and an imaging lens. The capture range is system dependent but can measure on the order of 100 microns of relative piston shift. The sensor is an improvement over similar technologies because it can measure and compensate for segment aberrations with tilt and piston adjustments.

Researchers at NASA’s Marshall Space Flight Center have patented a concept method for producing an even illumination pattern from a fiber-coupled laser diode. The innovation etches a diffractive optic pattern directly onto the end of an optical fiber. This technology reduces the Gaussian effect, present in conventional fiber optic cables, by using an optical fiber that is tipped with a diffractive surface so that the diffraction pattern imposed on light leaving the fiber concentrates the beam at nearly even intensity into a cross section of specified shape. The technology also reduces the weight and parts count of space experiments because it uses just one laser diode rather than multiple lasers for field illumination.

Scientists at NASA’s Marshall Space Flight Center have patented a system that provides a global radius of curvature (GRoC) estimation and control system (GRoCECS) for segmented telescope mirrors. Sensing and controlling a segmented mirror’s GRoC is necessary to increase resolution and ensure the best possible image quality when the mirror is a primary component of a telescope or beam director. Prior techniques involve placing sensors on mirror edges; however, edge sensors either do not provide sensitivity to the GRoC model at all or provide sensitivity at inadequate levels. In contrast, Marshall’s system works by exploiting a special set of mirror boundary conditions and the mirror’s influence functions to accurately estimate and control the segmented mirror’s radius of curvature. This control makes it possible not only to improve image quality but also to impose a required wavefront correction on incoming or outgoing light.

Innovators at NASA’s Marshall Space Flight Center have patented a compact, lightweight device that improves active wavefront coherency control across large optical apertures without the use of mechanical actuators. The invention is a multi-layered dielectric stack, to be used as a broadband phase modulator with up to 6.3 terahertz optical bandwidth. The technology introduces an optical interference coating design that exhibits a wide bandwidth region of high average transmission, capable of imparting a near-uniform phase modulation to all contributing frequency components of an incident optical signal. The more common Distributed Bragg Reflector interference configuration produces variations in transmission level, as well as a distortion of the transmitted signal. In contrast, the phase modulation of the newer device has a full-cycle range and causes minimal loss, minimal reflection, and minimal distortion.