New Span Opto-Technology (United States)

We demonstrate cis-to-trans transition based red light holographic recording in an azobenzene-liquid crystal (LC) polymer material following efficient crucial transition of trans-to-cis, which is prepared by selected wavelength light pre-illumination. The presence and orientation of soft liquid crystal impregnating the polymer backbone allows the cis intermediate states to hold for the stable red hologram recording and non-destructive readout. Using a 50 nm bandwidth light source at the center wavelength of 575 nm, we have efficient pre-illumination on the material. The diffraction efficiency of up to 2% can be achieved by a HeNe laser at 632.8 nm wavelength, and two-dimensional holograms of USAF resolution target are successfully recorded.

We report an enhanced laser induced polarization switching and holography in a novel photo-reconfigurable material system that contains polymer backbone impregnated by a soft liquid crystal material. The backbone of polymer chains is reconfigurable and the surrounding movable liquid crystal molecules are reoriented collectively anchoring toward the reconfigured polymer chains, resulting in remarkable enhancement of anisotropic refractive index modulation suitable for updatable holographic recording. The dynamic polymer-liquid crystal network strengthening concept enables significant enhancement of holographic performance with controllable updatability.

We report a multispectral imaging microscope with dynamic spectral reconfiguration capability. It operates based on a spatial filtering principle. The objective lens images the test specimen onto a dispersive grating surface. A dynamic spatial filter located at the Fourier plane of the 4-f lens group is used to select the desired spectral channel and spectral width for each spectral image diffracted by the grating. The reconfiguration capability enables the optimal spectral band selection for a specific application without hardware component modification. Successful experimental results validate the microscopic multispectral imaging configuration for practical applications.

We successfully demonstrated a multispectral remote sensing system based on our reported spectral imaging design. Dynamic spatial filters such as electronically selected slits were used to select desired bandpass spectrum at a Fourier plane of its optical system. Minimum 9 nm spectral resolution and 0.6° field of view has been achieved. In addition, compact prototype system packaging with a dimension of 17×11×8 inch has been attained. The real-time spectral imaging system capable of wide spectral band operation with simultaneous fine spectral resolution is particularly useful for a variety of defense, medical, and environmental monitoring applications.

The market demands for innovative, efficient, small package and single-mode light sources are always high because of their broad applications in scientific, medical, industrial, and commercial fields. The high photoluminescence quantum yield, photophysical and photochemical stability, and tunable emission wavelength make quantum dots ideal for a new generation of solid state light sources. We report on the realization of various single-mode light sources in the visible spectral band by using semiconductor quantum dots. The effective use of a waveguide structure can help achieve the divergence control of the output light beam. This technique may benefit the development for next generation light emitting diodes, optical communication, intelligent optical sensors, microprocessors, and nanoscale optical imaging systems.

A new dye-doped polymer film has been developed and typical optical storage properties are assessed using green CW and nano-second pulse lasers. Initial results indicate a large film refraction index modulation in the third decimal under light exposure, suggesting the film as potential medium for high-density holographic data storage applications.

Saccharomyces cerevisiae contains two genes, CIT1 and CIT2, encoding functional citrate synthase (K.-S. Kim, M. S. Rosenkrantz, and L. Guarente, Mol. Cell. Biol. 6:1936-1942, 1986). We show here that CIT2 encodes a nonmitochondrial form of citrate synthase. The DNA sequence of CIT2 presented provides a possible explanation for why the CIT2 product, unlike the CIT1 product, fails to be imported into mitochondria. While the products of these two genes are highly homologous, they diverge strikingly at their amino termini. The amino terminus of the CIT1 primary translation product extends 39 residues beyond the amino termini of Escherichia coli and porcine citrate synthases. This extension consists of a typical mitochondrial targeting motif. The amino terminus of the CIT2 primary translation product extends 20 residues beyond the amino termini of the E. coli and porcine enzymes. The CIT2-encoded extension is not homologous to that of CIT1, resulting in a nonmitochondrial localization of the product. The CIT2-encoded extension, however, does bear certain similarities to mitochondrial targeting sequences. The possible role of this sequence in targeting this CIT2 product to a nonmitochondrial organelle is discussed.