A novel hyperspectral imaging sensor is demonstrated that can enable breakthrough applications of hyperspectral imaging in domains not previously accessible. Our technology consists of a planar hyperspectral encoder combined with a traditional monochrome image sensor. The encoder adds negligibly to the sensor’s overall size, weight, power requirement, and cost (SWaP-C); therefore, the new imager can be incorporated wherever image sensors are currently used, such as in cell phones and other consumer electronics. In analogy to Fourier spectroscopy, the technique maintains a high optical throughput because narrow-band spectral filters are unnecessary. Unlike conventional Fourier techniques that rely on Michelson interferometry, our hyperspectral encoder is robust to vibration and amenable to planar integration. The device can be viewed within a computational optics paradigm: the hardware is uncomplicated and serves to increase the information content of the acquired data, and the complexity of the system, that is, the decoding of the spectral information, is shifted to computation. Consequently, system tradeoffs, for example, between spectral resolution and imaging speed or spatial resolution, are selectable in software. Our prototype demonstration of the hyperspectral imager is based on a commercially-available silicon CCD. The prototype encoder was inserted within the camera’s ~1 cu. in. housing. The prototype can image about 49 independent spectral bands distributed from 350 nm to 1250 nm, but the technology may be extendable over a wavelength range from ~300 nm to ~10 microns, with suitable choice of detector.
Fiber-optics (FO) have great potential for distributed sensing in various harsh environment applications. Their advantages include high resolution and multiplexing capabilities, inherent immunity to electromagnetic interference, and low weight/volume. However, their widespread adoption in commercial applications has been considerably limited by the high cost, size, weight, and lack of capabilities of the readout unit used to interpret the FO signals. PARC has developed a breakthrough wavelength shift detection (WSD) technology that is capable of reading out signals from wavelength-encoded FO and other optical sensors with high sensitivity using a compact, high-speed and low-cost unit. In this paper, its calibration and noise performance is demonstrated for high-resolution (up to 1,45 fm/√Hz) acoustic emission (AE) detection of fast (up to 1 MHz) dynamic strain signals.
Nanodiamond imaging is a new molecular imaging modality that takes advantage of nitrogen-vacancy (NV) centers in nanodiamonds to image a distribution of nanodiamonds with high sensitivity and high spatial resolution. Since nanodiamonds are nontoxic and are easily conjugated to biomolecules, nanodiamond imaging can potentially elicit physiological information from within a living organism. The position of the nanodiamonds is measured using optically detected electron spin resonance of the NVs. In a previous paper, we described a proof-of-principle nanodiamond imaging system with the ability to image in two dimensions over a 1×1 cm field of view and demonstrated imaging within scattering tissue. Here, we describe a second-generation nanodiamond imaging system with a field of view of 30×200 mm , and with three-dimensional imaging potential. The new system has a comparable spatial resolution of 1.2 mm FWHM and a sensitivity (in terms of the concentration of carbon atoms in a mm 3 voxel) of 1.6 mM mm 3 Hz −1/2 , a 3-dB improvement relative to the old system. We show that imaging at 2.872 GHz versus imaging at 2.869 GHz offers a 1.73× improvement in sensitivity with only a 20% decrease in resolution and motivate this by describing the observed lineshape starting from the NV spin Hamiltonian.
Nanodiamond imaging is a new molecular imaging modality that takes advantage of nitrogen-vacancy (NV) defects in nanodiamonds to image the distribution of nanodiamonds within a living organism with high sensitivity and high resolution. Nanodiamond is a nontoxic material that is easily conjugated to biomolecules, such that the distribution of nanodiamond within a living organism can be used to elicit physiological information. Unlike the tracers used in other molecular imaging modalities such as positron emission tomography (PET) and single photon emission computed tomography (SPECT), nanodiamonds are stable and thus allow longitudinal imaging of the same organism over a long time span. Unlike fluorescence-based molecular imaging that has a resolution degraded by photon scattering, the resolution of nanodiamond imaging is defined by the strength of a magnetic gradient.
To form an image, a magnetic field-free region is created, such as exists halfway between two identical magnets with north poles facing each other. Optical excitation pumps the NVs into a bright fluorescence state, and microwaves transfer them to a dark state, but only for those NVs within the field-free region and resonant with the microwaves. By rastering the field-free region across the sample, the changes in fluorescence yield the nanodiamond concentration. Images of nanodiamond phantoms within chicken breast have been recorded with a prototype system. By modifying the nanodiamond particles and enhancing the imaging system, it should be possible to approach 100 μm resolution and to increase the sensitivity to a 10 nanomolar carbon concentration per root Hz in a mm3 voxel.