The paper presents reflectance characteristics of plants. The objects of the research were the selected plants, taking
the various levels of organization and structure into consideration, as well as the state of plant health and growth.
Reflectance spectrum was analyzed in the range of wavelengths from 0,2 to 2,5 μm. The values of reflectance for three
wavelengths (λ<sub>1</sub>=850 nm, λ<sub>2</sub>=905 nm, λ<sub>3</sub>=1550 nm) were analyzed with the particular emphasis. The sample tests were
performed immediately after biological material taking and in the several 24-hour time intervals. The time intervals
enabled the process of plants wilting and drying. The reflectance measurements were repeated until the moment of plant
complete dried out. All measurements were performed with the use of the spectrometer Lambda 900 (Perkin Elmer)
equipped with the 150 mm integrating sphere PELA1001 dedicated for the measurements of the hemispherical
reflectance both of diffuse and specular type. On the basis of the obtained results one calculated the values of signal
ratios for the three selected wavelengths: 850/1550nm, 905/1550nm, and 850/905nm. The collected spectra and
reflectance characteristics enabled the analyses of both results similarities and differences, which enabled the
determination of the reflectance changes tendency associated with the typical processes occurring in plants.
The analyses of plants reflectance characteristics were made for the use of the laser system for identification of
terrain elements and their physico-chemical properties.
LIDAR system for real-time standoff detection of bio-agents is presented and preliminary experimental results are
discussed. The detection approach is based on two independent physical phenomena:
(1) laser induced fluorescence (LIF),
(2) depolarization resulting from elastic scattering on non-spherical particles.
The device includes three laser sources, two receiving telescopes, depolarization component and spectral signature
analyzing spectrograph. It was designed to provide the stand-off detection capability at ranges from 200 m up to several
kilometers. The system as a whole forms a mobile platform for vehicle or building installation. Additionally, it's
combined with a scanning mechanics and advanced software, which enable to conduct the semi-automatic monitoring of
a specified space sector.
For fluorescence excitation, 3-rd (355 nm) and 4-th (266 nm) harmonics of Nd:YAG pulsed lasers are used. They emit
short (~6 ns) pulses with the repetition rate of 20 Hz. Collecting optics for fluorescence echo detection and spectral
content analysis includes 25 mm diameter f/4 Newton telescope, Czerny Turner spectrograph and 32-channel PMT.
Depending on the grating applied, the spectral resolution from 20 nm up to 3 nm per channel can be achieved.
The system is also equipped with an eye-safe (1.5 μm) Nd:YAG OPO laser for elastic backscattering/depolarization
detection. The optical echo signal is collected by Cassegrain telescope with aperture diameter of 12.5 mm.
Depolarization detection component based on polarizing beam-splitter serves as the stand-off particle-shape analyzer,
which is very valuable in case of non-spherical bio-aerosols sensing.
Following article presents LIDAR for stand off detection of aerosols which was constructed in Institute of
Optoelectronics in Military University of Technology. LIDAR is a DISC type system (DIfferential SCattering) and is
based on analysis of backscattering signal for two wavelengths (λ<sub>1</sub> = 1064 nm and λ<sub>2</sub> = 532
nm) - the first and the
second harmonic of Nd:YAG laser. Optical receiving system is consisted of aspherical mirror lens, two additional
mirrors and a system of interference filters. In detection system of LIDAR a silicon avalanche photodiode and two
different amplifiers were used. Whole system is mounted on a specialized platform designed for possibility of LIDAR
scanning movements. LIDAR is computer controlled. The compiled software enables regulation of the scanning platform
work, gain control, and control of data processing and acquisition system. In the article main functional elements of
LIDAR are shown and typical parameters of system work and construction are presented. One presented also first results
of research with use of LIDAR. The aim of research was to detect and characterize scattering aerosol, both natural and
anthropogenic one. For analyses of natural aerosols, cumulus cloud was used. For analyses of anthropogenic aerosols one
used three various pyrotechnic mixtures (DM11, M2, M16) which generate smoke of different parameters. All scattering
centers were firstly well described and theoretical analyses were conducted. Results of LIDAR research were compared
with theoretical analyses and general conclusions concerning correctness of LIDAR work and its application were
In the work, analyses of scattering profile of chosen anthropogenic aerosols for two wavelengths (λ<sub>1</sub> = 1064 nm and
λ<sub>2</sub> = 532 nm) were made. As an example of anthropogenic aerosol three different pyrotechnic mixtures (DM11, M2,
M16) were taken. Main parameters of smoke particles were firstly analyzed and well described, taking particle shape and
size into special consideration. Shape of particles was analyzed on the basis of SEM pictures, and particle size was
measured. Participation of particles in each fixed fraction characterized by range of sizes was analyzed and parameters of
smoke particles of characteristic sizes and function describing aerosol size distribution (ASD) were determinated.
Analyses of scattering profiles were carried out on the basis of both model of scattering on spherical and nonspherical
particles. In the case of spherical particles Rayleigh-Mie model was used and for nonspherical particles analyses firstly
model of spheroids was used, and then Rayleigh-Mie one. For each characteristic particle one calculated value of four
parameters (effective scattering cross section σ<sub>SCA</sub>, effective backscattering cross section σ<sub>BSCA</sub>, scattering efficiency
Q<sub>SCA</sub>, backscattering efficiency Q<sub>BSCA</sub>) and value of backscattering coefficient β for whole particles population. Obtained
results were compared with the same parameters calculated for natural aerosol (cirrus cloud).
In the work, analyses of chosen materials were presented in order to analyze the possibility of development of a laser
scanning system. One showed results of research and analyses of data related to reflection characteristics of various
materials with consideration of different ranks of composition and structure complication. Analyses were carried out for
three wavelengths of electromagnetic radiation: λ<sub>1</sub> = 850 nm, λ<sub>2</sub> = 900 nm, λ<sub>3</sub> = 1500 nm in reference to both natural and anthropogenic materials. The influence of atmospheric extinction on values of received proportions of signals for the
chosen wavelengths was investigated and the method of signal correction was compiled. Correction was made taking
into account character of reflection obtained from materials, various atmospheric conditions stated by the atmospheric
visibility, and spectral characteristics of the atmospheric extinction. The proposed method of atmospheric extinction
correction provides minimization of real values falsification and decrease in obtained measurement errors, which does
not exceed the value of 5% for the analyses from a distance of 0.5 km with atmospheric visibility of 10 km, and for the
analyses from a distance of 1 km with atmospheric visibility of 20 km.