Development of portable Raman instrumentation over the past two decades has expanded in-field application of the method in areas including forensics, minerology, and plant pathology. Recently, Raman spectroscopy has attracted the interest of researchers from these fields because of its minimal interference from water and significant reduction of equipment costs. In this paper we demonstrate a hyperspectral Raman system capable of identifying minerals using very short integration times suitable for fast scanning of mining cores. Hyperspectral scans showed strong local Raman features of the known minerals in the core samples measured.

We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array at the detector plane. The two-dimensional aperture code is based on a row-doubled Hadamard mask with transmissive and opaque openings. The independent column code nature of the matrix makes for a mathematically well-defined pattern that spatially and spectrally maps the source information to the detector plane. Post-processing techniques on the data provide spectral estimates of the source. Comparative experimental results between a slit and coded aperture for emission spectroscopy from a CO(2) laser are demonstrated.

We describe a compact computational spectroscopy platform optimized for molecular recognition using metal nanoparticle assays. The objective is motivated by the urgent need for low-cost, portable and high-throughput sensors for point-of-care (POC) clinical diagnostics. Nanoparticle based sensing has been successfully demonstrated for diagnosis and monitoring of infectious diseases, drug discovery, proteomics, and biological agent detection. Molecular binding on the nanoparticle surface is transuded into an optical signal by modification of the nanoparticle extinction spectrum (via a shift in Localized Surface Plasmon Resonance) or by modification of the molecular scattering spectrum (via Surface Enhanced Raman Scattering).Translating a nanoparticle-based molecular recognition system into a functional miniature hand-held biosensor requires spectrometer designs optimized to large area nanoparticle assays and integrated spectral filtering to improve the signal specificity. Large population sampling with small population sensitivity is essential to highly sensitive nanoparticle assay analysis.We describe a multimodal multiplex spectroscopy (MMS) platform that samples the spectral response of up to 10(6) populations of 10-100 nanoparticles in parallel. The advantages of MMS approach include: extremely high signal throughput due to its large aperture and high resolution with small form factor. We will demonstrate a nanoparticle biosensor platform based on MMS. Ultimately, a fully integrated functional miniature nanoparticle based blosensor for real time disease diagnosis in whole blood assays can be realized.

We propose a new class of aperture-coded spectrometer that is optimized for the spectral characterization of diffuse sources. The instrument achieves high throughput and high spectral resolution by replacing the slit of conventional dispersive spectrometers with a more complicated spatial filter. We develop a general mathematical framework for deriving the required aperture codes and discuss several appealing code families. Experimental results validate the performance of the instrument.

We present experimental demonstrations of spectral diversity filters with spherical beam volume holograms for multimodal multiplex spectroscopy. Major properties of filters under diffuse-light illumination are discussed. The comparisons of spectral diversity between the transmission geometry holograms and the reflection geometry holograms are also studied. The results show that there is a trade-off between the degree of the spatial coherence of the source and the spectral diversity of the filter. We also conclude that the reflection geometry holograms have better spectral diversity and less sensitivity to the spatial coherence of the source.

Optical diagnostics in biological materials are hindered by fluorescence and scattering. We have developed a multimodal, multiplex, coded-aperture Raman spectrometer to detect alcohol in a lipid tissue phantom solution.

We present the first implementation of a Fourier-transform spherical beam holographic spectrometer with considerably better sensitivity compared to conventional grating spectrometers. We use this idea to demonstrate a compact spectrometer that is usually encountered in optical sensing with great potential for measuring weak spatially incoherent signal.

We present a flexible design for a static, multimodal, multiplex spectrometer which is optimized for the weak incoherent sources that are common in biomedical applications. Simultaneous high throughput and resolution are achieved in a single-shot measurement via 2-D aperture encoding. The resulting computational problem is well-conditioned and easily invertible.

We investigate the application of static, multimodal, multiplex spectrometers to the detection of the Raman spectrum of ethanol in blood and tissue. These spectrometers are optimized for use with weak, incoherent sources, and enable relatively high sensitivity in a completely integrated system.

The spherical beam volume hologram, recorded by a plane wave and a spherical beam, is investigated for spectroscopic applications in detail. It is shown that both the diffracted and the transmitted beam can be used for spectroscopy when the hologram is read with a collimated beam. A new method is introduced and used for analysis of the spherical beam volume hologram that can be extended for analysis of arbitrary holograms. Experimental results are consistent with the theoretical study. It is shown that the spherical beam volume hologram can be used in a compact spectroscopic configuration when the transmitted beam is monitored. Also, on the basis of the properties of the spherical beam hologram, the response of a hologram recorded by a plane wave and an arbitrary pattern is predicted. The information can be used to optimize holographic spectrometer design.

Joint target triangulation and estimation from spatio-spectral tracking using a rotational shear interferometer on a telescope is described. The system is based on an array of three eight inch off-axis parabolic reflector telescopes with CCD cameras used for imaging.