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THE ENEA LIDAR FLUOROSENSOR: 
RESULTS OF LABORATORY EXPERIMENTS ON PHYTOPLANKTON 
R.BARBENI, F.COLAO, R.FANTONI, R.GUARINI 1 , A.PALUCQ, S.RIBEZZO 
ENEA, Dipartimento Innovazione, Settore Elettroottica e Laser 
P.O. Box 65 
1-00044 Frascati RM (Italy) 
P.CARLOZZL G.TORZILLO, E. PELOSI 
CNR, Centro Studio Microorganismi Autotrofi 
Pie delle Cascine 27 
1-50144 Firenze (Italy) 
ABSTRACT 
The lidar fluorosensor system available at ENEA Frascati has been used for a series of laboratory measurements 
on brackish-water and marine phytoplankton grown in photobioreactors with the proper saline solution. The ef 
ficiency of different excitation wavelength ranging from the UV to the visible region (300 to 500 nm) has been 
measured on different species of algae. Detection limits have been tested upon non-photoinhibited samples. The 
collected data will form a database to be used in forecoming campaigns on open sea. Results of a new technique 
based on two laser pump and probe excitation for remotely monitoring the in-vivo photosynthetic activity will 
be presented as well. 
KEYWORDS: Remote Sensing, Fluorescence, Phytoplankton, Probe-Pump Technique. 
1 - INTRODUCTION 
The ENEA lidar fluorosensor has been designed to be able to measure both Laser Induced Fluorescence (LIF) 
spectra and fluorescence decay times in different spectral regions from solid and liquid targets. The apparatus, 
already used in open air as well as in laboratory measurements, has been proved to be a very flexible and pow 
erful tool allowing to measure the most important bio-physical parameters of vegetation from LIF spectra. By 
inserting a Raman shifter along the transmitter line, it is possible to investigate the fluorescence efficiency vs 
exdtati on wavelength at some different excitation lines in the UV - near UV region The recent acquisition of 
an additional Nd:YAG laser source allowed for testing the effectiveness of a new LIF technique based on two 
laser excitation. From both laboratory measurements [1,2] and field campaigns [3,4] an extensive data base of 
remote sensed data has been built for remotely sensing sea and terrestrial vegetation features. 
In the following, the XeCl laser based lidar fluorosensor built at the ENEA Centre in Frascati and 
operated nowadays from a mobile station, is briefly described in the configuration for spectral resolved LIF 
measurements upon excitation with one or two laser sources. Laboratory data collected from small photobiore 
actors and large water columns are presented and discussed. 
2 - MATERIALS AND METHODS 
2.1. The ENEA lidar fluorosensor 
The apparatus, extensively described in [1], is composed by all optical and electronic sub-assemblies typical for 
fluorescence remote sensing,. Laser transmitter characteristics are reported in Table I. * 
* Student