Additive manufacturing, such as laser sintering or melting of additive layers, can produce parts rapidly at small volume and in a factory setting. To ensure the additive manufactured parts are of high quality, a real-time non-destructive evaluation (NDE) technique is required to detect defects while they are being manufactured. The present invention describes an in-situ (real-time) inspection unit that can be added to an existing additive manufacturing (AM) tool, such as an FDM (fused deposition modeling) machine, or a direct metal laser sintering (DMLS) machine, providing real-time information about the part quality, and detecting flaws as they occur. The information provided by this unit is used to a) qualify the part as it is being made, and b) to provide feedback to the AM tool for correction, or to stop the process if the part will not meet the quality, thus saving time, energy and reduce material loss.

In order to avoid friendly fire incidents in the combat theater, novel covert identification systems and methods of identifying friendly forces are provided. The systems include at least a spectroscopic imaging device and a marker that interact with each other by using a synchronized, predetermined filter tuning sequence. The filter tuning sequence enables interacted photons to wavelength hop according to the predetermined tuning sequence. As a result, the covert identification system allows friendly forces to clearly identify each while avoiding detection by enemy forces that employ conventional broadband and night vision sensors.

Methods and apparatus for obtaining a vibrational circular dichroism (VCD) image using a discrete frequency infrared (DFIR) microscope are disclosed. The method includes generating a pulsed laser beam comprising a spectral frequency, which may be tunable; modulating the laser beam to generate circularly polarized light; illuminating a sample and collecting, and detecting an optical signal transmitted or transflected from the location of the sample. The detected signal is demodulated at, for example, both the pulse frequency and the sum or difference of the pulse frequency and the modulating frequency to obtain an intensity value that correspond to the absorbance, and a polarization-dependent value that corresponds to the VCD. Other configurations of the apparatus may be employed to measure VCB and VLD.

Methods and apparatus for obtaining a vibrational circular dichroism (VCD) image using a discrete frequency infrared (DFIR) microscope are disclosed. The method includes generating a pulsed laser beam comprising a spectral frequency, which may be tunable; modulating the laser beam to generate circularly polarized light; illuminating a sample and collecting, and detecting an optical signal transmitted or transflected from the location of the sample. The detected signal is demodulated at, for example, both the pulse frequency and the sum or difference of the pulse frequency and the modulating frequency to obtain an intensity value that correspond to the absorbance, and a polarization-dependent value that corresponds to the VCD. Other configurations of the apparatus may be employed to measure VCB and VLD.

Methods and apparatus for obtaining a corrected digital mode spectrum for a chemically strengthened (CS) substrate having a curved surface are disclosed. The methods include digitally capturing transverse magnetic (TM) and transverse electric (TE) mode spectra of the CS substrate to form a digital mode spectrum image using an evanescent prism coupling system having a system calibration for measuring flat CS substrates. The method further includes establishing a calibration correction based on the difference in the digitally captured TM and TE mode spectra as compared to a reference TM and TE mode spectra for a reference CS substrate. The calibration correction is applied to the digital mode spectrum image to form the corrected digital mode spectrum image, which can be processed using the system calibration for measuring flat CS substrates to determine a refractive index profile and stress characteristics for the curved CS substrate.

Disclosed are optical computing devices that employ birefringent optical elements configured for use in optical computing devices. One optical computing device includes a polarizer configured to generate at least x polarized light and y polarized light, a birefringent integrated computational element configured to optically interact with a substance and the polarizer, thereby generating optically interacted light, and at least one detector arranged to receive the optically interacted light and generate an output signal corresponding to a characteristic of the substance.

Disclosed are optical computing devices that employ birefringent optical elements configured for use in optical computing devices. One optical computing device includes a polarizer configured to generate at least x polarized light and y polarized light, a birefringent integrated computational element configured to optically interact with a substance and the polarizer, thereby generating optically interacted light, and at least one detector arranged to receive the optically interacted light and generate an output signal corresponding to a characteristic of the substance.

A novel detection system and method is presented, where a two-bead receptor method is used for capturing pathogens, with one type of bead being magnetic and having a size of 3 microns or smaller, and the other type being polymeric and having a size of 3 microns or larger. The first type is used to concentrate a pathogen; the latter is used to create a detectable signal. Fast sensitive detection is achieved by collecting the optical signal created by the distortion of a homeotropically aligned chromonic azo dye in the presence of captured pathogens.

A method includes attaching two or more beads to each unit of one or more units of a chemical component in a sample, to form, for each unit of the chemical component, a multi-bead complex including two or more beads and the unit of the chemical component; placing the sample on a surface of an image sensor; at the image sensor, receiving light originating at a light source, the received light including light reflected by, refracted by, or transmitted through the beads of the multi-bead complexes; at the image sensor, capturing one or more images of the sample from the received light; and identifying, in at least one of the images of the sample, separate multi-bead complexes, the identifying of the separate multi-bead complexes including associating the two or more beads of each of the multi-bead complexes based on proximity to one another.

A birefringence measurement device includes a light flux generator for generating light flux, a light flux irradiator for irradiating a measurement target with the light flux in a predetermined polarization state, an imaging optical system for forming an image from light flux transmitted through the measurement target, a polarization/diffraction grating positioned within the imaging optical system, an image pickup for generating a light-dark signal related to brightness of the image, and an output for outputting information regarding a phase difference for the light flux. The phase difference resulting from the transmission through the measurement target is determined on the basis of the light-dark signal. The image pickup generates the light-dark signal for the image based on at least one beam of diffracted light from among a plurality of beams of diffracted light produced by the grating. A two-dimensional distribution of birefringence is obtained in real time without a rotating mechanism.