mechanical and fluid systems
Wafer Level Microchannel Fabrication Process for Lab-on-a-Chip Devices
The microchannel chip is created from a silicon bottom wafer and Pyrex top wafer anodically bonded. Specialized microbeads with specific structure and surface chemistry are placed along the channels. Different species of analyte molecules will interact more strongly with the column chemistry and will therefore take longer to traverse the column, i.e., have a longer retention time. In this way, the channels separate molecular species based on their chemistry. The specific shape and surface chemistry of these microchannels do more than just move analyte moleculesthe molecules are separated by how they are affected by the channels chemistry for expedited analysis. Paired with mass spectroscopy or ChemFET technology, this technology could enhance research and development in microchemistry, microfluidics, and lab-on-a-chip technology. Another embodiment of this invention includes microposts inside the microfluidic channel for particle separation, rather than using microbeads. The silicon microposts can be built inside of silicon microfluidic channel by MEMS technology. The size of microposts can vary depending on the application. The microposts function as an in-line filter to block unwanted big particles and protect the microfluidic chip. Furthermore, micropost chips with microvalves can physically select different size cells, molecules, viruses etc. It can also be used to select different particles in bioengineering and pharmaceutical testing.
Multicolor detectors for ultrasensitive long-wave imaging cameras
This technology addresses the need for Terahertz imaging which is necessary for next generation instruments. The detector involves two innovations: a quasiparticle (QO) filter arrangement that enables a compact multicolor spectrum at the focal plane, and a THz antenna readout by up to three bolometers. This innovation achieves high efficiency by greatly reducing high, frequency-dependent microstrip losses, and pixel compactness is achieved by eliminating the need for bulky filters in the focal plane. The zeptobolometer is a small TES bolometer, on the scale of a few microns, which can be readily coupled through an impedance-matching resistor to a metal or dielectric antenna. The bolometer is voltage-biased in its superconducting transition, allowing the use of superconducting RF multiplexers to read out large arrays. The antenna is geometrically tapped at three locations so as to efficiently couple radiation of three distinct wavelengths to the individual TESs.
Real-Time LiDAR Signal Processing FPGA Modules
The developed FPGA modules discern time-of-flight of laser pulses for LiDAR applications through the correlation of a Gaussian pulse with a discretely sampled waveform from the LiDAR receiver. For GRSSLi, up to eight cross-correlation engines were instantiated within a FPGA to process the discretely sampled transmit, receive pulses from the LiDAR receiver, and ultimately measure the time-of-flight of laser pulses at 20-picosecond resolution. Engine number is limited only by the resources within the FPGA fabric, and is configurable with a constant. Thus, potential time-of-flight measurement rates could go well beyond the 200-KHz mark required by GRSSLi. Additionally, the engines have been designed in an extremely efficient manner and utilize the least amount of FPGA resources possible.
Novel Superconducting Transition Edge Sensor
NASA technologists have developed several devices using this TES design. For example, innovators at NASA Goddard Space Flight Center have implemented an integrated system for defining the frequency response for dual- polarized microwave sensors for observations of the cosmic microwave background (CMB) in order to probe the evolution of the early universe. Precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. Cosmological observations have have hinted that the universe experienced a brief period of rapid expansion called inflation early in its history that is believed to be responsible for the flatness of the universe and the origin of structure. If inflation occurred, it would have produced a gravitational wave background that is evidenced by a small but distinct polarized signature on the cosmic microwave background. The detector for CMB polarization measurements uses large format arrays of background-limited detectors in the form of feedhorn-coupled, TES based sensors. Each linear orthogonal polarization from the feedhorn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization.
Impedance Matched to Vacuum, Invisible-edge Diffraction Suppressed Mirror
The impedance mismatch between the edge of the mirror and the vacuum beyond it is responsible for the occurrence of diffraction. In order to eliminate diffraction the impedance mismatch must be eliminated. To achieve this a gradient of wavelength scale via nanostructures are fabricated on the surface of the mirror substrate. The via nanostructure gradient density is highest at the edge of the mirror and decreases linearly, or in a stepwise fashion, towards the center of the mirror where the density is the lowest. This technique effectively matches the impedance of the mirror to that of free space and allows for 100% transmission of incident light to the reflective layer of the mirror. This is effective for a wavelength of choice. Broadband capability can be achieved by multiple layers of via nanostructures decreasing in feature size from top to bottom layer.
Fourier Transform Spectroscopy Phase Detector/Demodulator
In conventional measurements, a reference laser signal runs through the device and is guided to a separate detector and triggers capture of the spectral signal. This old method restricts usable wavelengths to less than half the frequency of the laser. As part of a modification that does away with this limitation, a mirror slides along the device at a constant speed during the scan. Unavoidable velocity variations require linearization or resampling with respect to a known reference for which a metrology laser is employed. The laser is guided as before but the signal is sent to a different detector where the timing information is stored and used to mathematically velocity correct the original signal in post processing. The problem with this approach is that extra hardware, post processing and tuning are required, and the process can be somewhat difficult to perform. This method digitizes the laser signal in a separate channel along with spectra data, which eliminates the hardware required in previous methods, then demodulates the laser signal with a synthetic quadrature phase detector combined with phase tracking to derive the proper slide position for each data point. This method only requires inexpensive 24 bit audio digitizers, rather than the more expensive event counters of the previous method. The new method does not require tuning, and high resolution data can be obtained at any wavelength.
Miniaturized Laser Heterodyne Radiometer
This instrument uses a variation of laser heterodyne radiometer (LHR) to measure the concentration of trace gases in the atmosphere by measuring their absorption of sunlight in the infrared. Each absorption signal is mixed with laser light (the local oscillator) at a near-by frequency in a fast photoreceiver. The resulting beat signal is sensitive to changes in absorption, and located at an easier-to-process RF frequency. By separating the signal into a RF filter bank, trace gas concentrations can be found as a function of altitude.
Remote Sensing Based on Fluorescence LIDAR
As originally developed, BILI is a novel planetary Astrobiology instrument based on a real-time technique of remote detection and discrimination of bio-signatures dispersed in the ground-level planetary atmosphere, leveraging the fluorescence lidar technology. Capabilities of this first planetary atmospheric bio-indicator survey instrument will dramatically increase the probability of finding the signatures of extraterrestrial life by performing atmospheric volume scans of hundreds of meters in a radial direction around the rover or lander. The Bio-Indicator Lidar technology employs real-time aerosol particle detection and discrimination based on two physical variables: particle fluorescence and particle size in the bio-discrimination space.
electrical and electronics
Magnetic Shield Using Proximity Coupled Spatially Varying Superconducting Order Parameters
The invention uses the superconducting "proximity effect" and/or the "inverse proximity effect" to form a spatially varying order parameter. When designed to expel magnetic flux from a region of space, the proximity effect(s) are used in concert to make the superconducting order parameter strongly superconducting in the center and more weakly superconducting toward the perimeter. The shield is then passively cooled through the superconducting transition temperature. The superconductivity first nucleates in the center of the shielding body and expels the field from that small central region by the Meissner effect. As the sample is further cooled the region of superconducting order grows, and as it grows it sweeps the magnetic flux lines outward.
Non-Scanning 3D Imager
NASA Goddard Space Flight Center's has developed a non-scanning, 3D imaging laser system that uses a simple lens system to simultaneously generate a one-dimensional or two-dimensional array of optical (light) spots to illuminate an object, surface or image to generate a topographic profile. The system includes a microlens array configured in combination with a spherical lens to generate a uniform array for a two dimensional detector, an optical receiver, and a pulsed laser as the transmitter light source. The pulsed laser travels to and from the light source and the object. A fraction of the light is imaged using the optical detector, and a threshold detector is used to determine the time of day when the pulse arrived at the detector (using picosecond to nanosecond precision). Distance information can be determined for each pixel in the array, which can then be displayed to form a three-dimensional image. Real-time three-dimensional images are produced with the system at television frame rates (30 frames per second) or higher. Alternate embodiments of this innovation include the use of a light emitting diode in place of a pulsed laser, and/or a macrolens array in place of a microlens.