Refractive index measurement of biological particles in visible region

摘要

Optical cross-sections of biological warfare simulants, killed agents, and live agents are needed to assess thestandoff detection performance of active lidar and passive FTIR systems. To aid in this investigation, Johns HopkinsUniversity Applied Physics Laboratory (JHU/APL) has developed a technique to determine the index of refraction ofbiological materials in the visible region using a combination of transmission measurements and anomalous diffractiontheory (ADT). The spectral measurements using a dual beam grating spectrometer provide a basis for calculating theoptical cross section of suspended particles. ADT is then used to convert the cross section result into index of refraction.A summary of this procedure is described along with the results for silica microspheres and Bacillus glob ijii (BG). Acomparison of these results to published data is also presented.