Portable Integrated Fourier Ptychographic Microscope

NASAs digital projection focusing schlieren system is attached to a commercial-off-the-shelf camera. For focusing schlieren measurements, it directs light from the light source through a condenser lens and linear polarizer towards a beam-splitter where linear, vertically-polarized component of light is reflected onto the optical axis of the instrument. The light passes through the patterned LCD element, a polarizing prism, and a quarter-wave plate prior to projection from the assembly as left- or right-circularly polarized light. The grid-patterned light (having passed through the LCD element) is directed past the density object onto a retroreflective background (RBG) that serves as the source grid. Upon reflection off the RBG, the polarization state of light is mirrored. It passes the density object a second time and is then reimaged by the system. Upon encountering the polarizing prism the second time, the light is slightly offset. This refracted light passes through the LCD element, now serving as the cutoff grid, for a second time before being imaged by the camera. The LCD element can be programmed to display a variety of grid patterns to enable sensitivity to different density gradients. the color properties of the LCD can be leveraged in combination with multiple colored light sources to enable simultaneous multi-color, multi-technique data collection.

The handheld digital microscope features a 3D-printed chassis to house its hardware, firmware, and rechargeable Li-ion battery with built-in power management. It incorporates an internal stainless-steel cage system to enclose and provide mechanical rigidity for the optics and imaging sensor. To reduce the microscope’s size, yet retain high spatial resolution, engineers devised an optical light path that uniquely folds back on itself using high reflectivity mirrors, thus significantly reducing internal volume. Imaging control and acquisition is performed using a secure web-based graphical user interface accessible via any wireless enabled device. The microscope serves as its own wireless access point thus obviating the need for a pre-existing network. This web interface enables multiple simultaneous connections and facilitates data sharing with clinicians, scientists, or other personnel as needed. Acquired images can be stored locally on the microscope server or on a removable SD card. Data can be securely downloaded to other devices using a range of industry standard protocols. Although the handheld digital microscope was originally developed for in-flight medical diagnosis in microgravity applications, prototypes were thoroughly ground-tested in a variety of environments to verify the accurate resolve of microbial samples for identification and compo-sitional analysis for terrestrial field use. Owing to its portability, other applications demanding rapid results may include research, education, veterinarian, military, contagion disaster response, telemedicine, and point-of-care medicine.

This invention provides a method and system for fabricating a biomarker sensor array by dispensing one or more entities using a precisely positioned, electrically biased nanoprobe immersed in a buffered fluid over a transparent substrate. Fine patterning of the substrate can be achieved by positioning and selectively biasing the probe in a particular region, changing the pH in a sharp, localized volume of fluid less than 100 nm in diameter, resulting in a selective processing of that region. One example of the implementation of this technique is related to Dip-Pen Nanolithography (DPN), where an Atomic Force Microscope probe can be used as a pen to write protein and DNA Aptamer inks on a transparent substrate functionalized with silane-based self-assembled monolayers. But it would be recognized that the invention has a much broader range of applicability. For example, the invention can be applied to formation of patterns using biological materials, chemical materials, metals, polymers, semiconductors, small molecules, organic and inorganic thins films, or any combination of these.

Fluid lensing exploits optofluidic lensing effects in two-fluid interfaces. When used in such interfaces, like air and water, coupled with computational imaging and a unique computer vision-processing pipeline, it not only removes strong optical distortions along the line of sight, but also significantly enhances the angular resolution and signal-to-noise ratio of an otherwise underpowered optical system. As high-frame-rate multi-spectral data are captured, fluid lensing software processes the data onboard and outputs a distortion-free 3D image of the benthic surface. This includes accounting for the way an object can look magnified or appear smaller than usual, depending on the shape of the wave passing over it, and for the increased brightness caused by caustics. By running complex calculations, the algorithm at the heart of fluid lensing technology is largely able to correct for these troublesome effects. The process introduces a fluid distortion characterization methodology, caustic bathymetry concepts, Fluid Lensing Lenslet Homography technique, and a 3D Airborne Fluid Lensing Algorithm as novel approaches for characterizing the aquatic surface wave field, modeling bathymetry using caustic phenomena, and robust high-resolution aquatic remote sensing. The formation of caustics by refractive lenslets is an important concept in the fluid lensing algorithm. The use of fluid lensing technology on drones is a novel means for 3D imaging of aquatic ecosystems from above the water's surface at the centimeter scale. Fluid lensing data are captured from low-altitude, cost-effective electric drones to achieve multi-spectral imagery and bathymetry models at the centimeter scale over regional areas. In addition, this breakthrough technology is developed for future in-space validation for remote sensing of shallow marine ecosystems from Low Earth Orbit (LEO). NASA's FluidCam instrument, developed for airborne and spaceborne remote sensing of aquatic systems, is a high-performance multi-spectral computational camera using Fluid lensing. The space-capable FluidCam instrument is robust and sturdy enough to collect data while mounted on an aircraft (including drones) over water.

This NASA technology transforms a conventional infrared (IR) imaging system into a multi-wavelength imaging pyrometer using a tunable optical filter. The actively tunable optical filter is based on an exotic phase-change material (PCM) which exhibits a large reversible refractive index shift through an applied energetic stimulus. This change is non-volatile, and no additional energy is required to maintain its state once set. The filter is placed between the scene and the imaging sensor and switched between user selected center-wavelengths to create a series of single-wavelength, monochromatic, two-dimensional images. At the pixel level, the intensity values of these monochromatic images represent the wavelength-dependent, blackbody energy emitted by the object due to its temperature. Ratioing the measured spectral irradiance for each wavelength yields emissivity-independent temperature data at each pixel. The filter’s Center Wavelength (CWL) and Full Width Half Maximum (FWHM), which are related to the quality factor (Q) of the filter, are actively tunable on the order of nanoseconds-microseconds (GHz-MHz). This behavior is electronically controlled and can be operated time-sequentially (on a nanosecond time scale) in the control electronics, a capability not possible with conventional optical filtering technologies.