Solid State Research Quarterly Technical Report 2003:2
Abstract
A test bed using UV light-emitting diodes for detecting biological agent aerosols has been designed. An experimental apparatus was used to measure the elastic scattering and fluorescence signals from single bacterial spores illuminated by low-power 408-nm laser diode radiation. GaSb/GaInAsSb/GaSb epilayers have been transferred to GaAs wafers by atomic wafer fusion without mechanical pressure at temperatures as low as 350 deg C, followed by GaSb substrate removal. The fusion without pressure results in significantly improved structural and optical propeities. Lithographically defined microstructures have been used to control the growth of the organic crystalline electro-optic material DAST on silicon substrates. Mach Zehnder interferometer modulators have been built utilizing this technique, and measurements indicate that the electro-active coefficient of DAST is an order of magnitude greater than that of LiNbO3. An angle-resolved scattering detection system has been designed and implemented for use at 157-nm wavelength. In this test bed, scattered rays can be collected to 4 deg from the directional ray of the specularly transmitted beam, corresponding to spatial wavelengths of surface roughness <2 micrometers, over a dynamic range of 7 orders of magnitude; angular sensitivity can be extended to 0.5 deg, but with a dynamic range of 5 orders of magnitude.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 17, 2003
- Accession Number
- ADA417982
Entities
Organizations
- Massachusetts Institute of Technology