We are pleased to provide downloads, or links, to a number of papers on LiDAR which were produced using Vertilon's PhotoniQ DAQs.
Hyperspectral Fluorescence Lifetime Lidar for Geological Exploration
Bruno Bourliaguet, Nicolas Hô, Francis Généreux, Frédéric Émond, Félix Cayer, François Babin
SPIE Proceedings, Volume 7478, Geological Remote Sensing, 31 August 2009
Copyright ©2009 The International Society for Optical Engineering
We have developed a small, relatively lightweight and efficient lidar instrument for remotely detecting and classifying minerals. The system is based on a pulsed, eye-safe, diode pumped Nd:YAG laser, tripled (355nm) or quadrupled (266nm), for UV excitation of minerals, which then fluoresce with a typical spectrum and lifetime. Fluorescence is detected through a telescope / filter / fiber bundle / spectrograph / multi-channel detector system capable of photon counting. Transmission and detection efficiency have been optimized to reduce the need for high optical excitation energy. Detection electronics are based on gated charge integration using a multi-anode photomultiplier tube. Spectra shown are measured in the 420 to 720 nm visible range with 355 nm laser excitation. Results show that it is relatively easy to distinguish between vegetation and non-vegetation spectra using lifetime data. Lifetime of vegetation is relatively short when compared to the mineral samples investigated. Although results shown are measured in a controlled environment on the ground, the system is being developed for eventual use in a low altitude airborne application. System parameters are presented and upgrade paths are discussed.
Franz Immler, Ingo Beninga, Wilfried Ruhe, Bernhard Stein, Bernd Mielke, Soeren Rutz, Özden Terli, Otto Schrems, Alfred Wegener
Institute for Polar and Marine Research, Bremerhaven, Germany
A newly designed Compact Cloud and Aerosol LIDAR (ComCAL) that was built for the deployment in field campaigns on ground and on mobile platforms like aboard the research vessel Polarstern. The automated system is particularly suited for tropospheric aerosol research within the altitude range from 0.7 to 20 km. As an emitter it uses a frequency doubled and tripled Nd:YAG laser. It measures elastic backscatter and the depolarization at 532 nm and 355 nm as well as inelastic scattering with a 32-channel spectrograph. Recently, it was shown that biomass burning aerosol fluoresces when irradiated by a UV laser beam while other aerosol types do not fluoresce. Beside the detection of N2 and H2O Raman scattering, fluorescence of aerosols can be detected by the new optical set-up of the lidar system. The measurement of wavelength dependent backscatter, extinction, depolarization, and fluorescence makes a detailed study of atmospheric aerosols possible. The new lidar system determines optical properties of aerosols and their vertical distribution. The aerosol types, their origins and abundance can be deduced from that data. These are important parameters for the study of the effect of natural and anthropogenic aerosols on the earth’s climate.
Development of fluorescence-based LIDAR technology for biological sensing
Per Jonsson, Fredrik Kullander, Mikael Tiihonen, Melker Nordstrand, Torbjørn Tjærnhage, Pær Wæterby, Gøran Olofsson, Mikael Lindgren
Materials Research Society Symposium, Volume 883
Copyright ©2005 Materials Research Society
Results for the on-going development of biological warfare agents (BWA) detection systems based on spectral detection of ultraviolet (UV) laser induced fluorescence (LIF) are presented. A compact optical parametric oscillator (OPO) with intracavity sum-frequency mixing (SFM) to generate 293 nm UV laser irradiation was developed. The OPO/SFM device was pumped by a diode-pumped Nd:YAG laser (1064 nm), including subsequent second-harmonic generation (SHG) in an external periodically poled KTiOPO4 (PPKTP) crystal. The laser generated 1.8 ns pulses at 100 Hz with an average power of 44 mW at 532 nm. The whole system could be used to deliver approximately 30 uJ laser irradiation per pulse (100 Hz) at 293 nm. The spectral detection part of the system consists of a grating and a photomultiplier tube (PMT) array with 32 channels, which can measure fluorescence spectra in the wavelength band from 250 nm to 800 nm. The detector system was designed along with a trigger laser to enable measurement of fluorescence spectra from an individual aerosol particle of simulants for BWA upon excitation with a single nanosecond laser pulse. Demonstrated are the successful detection and spectral characterization of simulants for BWA, i.e., Bacillus atrophaeus (BG), Bacillus thuringiensis (BT), and Ovalbumin (OA).
