Special Coverage


Active Layer Optimization in Ultra-Thin, Surface-Parallel, Deformable Mirrors

This method enables low-cost, lightweight, active mirrors with a large dynamic range and improved actuation characteristics. NASA’s Jet Propulsion Laboratory, Pasadena, California A design methodology was developed that optimizes the performance of active mirrors. Patterns of parameterized ellipsoidal actuators are overlaid onto the mirror, and then numerically optimized to improve performance of the mirror in optical modes that are typically difficult to correct, while also improving performance in other optical modes.

Posted in: Tech Briefs, Photonics, Optics, Articles, Briefs


Monolithic Dual Telescope for Compact Biaxial Lidar

Goddard Space Flight Center, Greenbelt, Maryland A document discusses the Ultra Compact Cloud Physics Lidar, a biaxial lidar with a narrow receiver field of view. It requires tight optical alignment between the transmitter and receiver paths while flying on various aircraft over various temperatures and in the presence of vibration. To achieve optical crossover as close to the lidar as possible, the transmit and receive telescopes must be built very closely to each other.

Posted in: Tech Briefs, Physical Sciences, Photonics, Articles, Briefs, TSP


Passive Aerosol Cloud Suite

High-accuracy polarization measurements can be made with high angular density across full images. Goddard Space Flight Center, Greenbelt, Maryland The Passive Aerosol Cloud Suite (PACS) is an imaging polarimeter that employs wide field-of-view (FOV) optics to obtain a highly accurate polarimetric signal across an image with hyperangle, multiangle views. PACS is designed to measure the array of parameters necessary to retrieve aerosol and cloud microphysical characteristics. The final goal of PACS is a flight model able to compete for a position on the Aerosol-Cloud-Ecology (ACE) Decadal Survey mission or other space-based platforms, but adaptations of the basic technology to airborne and ground-based applications are anticipated.

Posted in: Tech Briefs, Photonics, Optics, Articles, Briefs, TSP


Solar Pumped Fiber Laser for Solar Sail Propulsion and Remote Power Transfer

The photovoltaic capability of any instrument can be enhanced by delivering extra power via a space-based, broadband laser beam. Goddard Space Flight Center, Greenbelt, Maryland A new method has been developed to create coherent laser light efficiently with direct optical coupling of the Sun’s energy into the gain medium for multiple uses. New advances in solar cell photovoltaic (PV) technologies have greatly improved their efficiencies, mostly by improving their ability to convert many wavelengths or wider bands of the solar spectrum to electricity. New advances in actively doped fibers and optical glasses have been shown to produce very broad, multi-line absorption bands as well as stimulated emission lines, or laser lines. By designing the optical cavity system to feed back all emission bands into the gain media for amplification, a multi-wavelength source can be generated requiring no electronics.

Posted in: Tech Briefs, Physical Sciences, Photonics, Briefs


ELID Grinding of Large Aspheres

Goddard Space Flight Center, Greenbelt, Maryland This work focused on a manufacturing process to produce silicon carbide optical surfaces with low mid-spatial surface errors. Mid-spatial frequency (MSF) and high-spatial frequency (HSF) surface errors in the grinding of fast aspheres are amplified in hard ceramics like silicon carbide due to cyclic tool wear rates, vibration, and tool deformation.

Posted in: Tech Briefs, Photonics, Briefs


Systems and Methods for Localized Surface Plasmon Resonance Sensing

This innovation uses an optical fiber having a metallic dot array on its tip, a light source coupled to the optical fiber via a light coupler, and a spectrometer coupled to the optical fiber via the coupler. Marshall Space Flight Center, Alabama Recently, there is widespread interest in the development of chemical and biochemical sensors based on plasmonic resonance of metallic nanostructures. In the localized surface plasmon resonance (LSPR) for nanometer-sized metallic structures, a resonant oscillation of the conduction electrons within the metallic nanostructures gives rise to an enhanced scattering and absorption of light. The LSPR sensing requires simpler instrumentation than surface plasmon resonance (SPR).

Posted in: Tech Briefs, Photonics, Briefs


Advances in Manufacturing Fiber Optic Gyroscopes

Since it was first proposed in 1975, the fiber optic gyroscope (FOG) has steadily improved in performance and manufacturability. Now a mainstream, high-volume manufactured product with performance approaching Ring Laser Gyros (RLG), FOGs offer substantial advantages over competitive technologies in terms of reliability, cost, and complexity. Optical fiber splicing and related processes are at the core of this achievement.

Posted in: Features, Photonics, Briefs