Environmental Diagnostic

The pollutant and aerosol monitoring in the atmosphere is determinant to control air quality and climatic effects.
In this field, diagnostic systems such as DIAL (Differential Absorption Lidar) acquire a great relevance, as long as they are able to measure in real time small concentrations of pollutants in function of distance (until 4,5 Km) with good spatial resolution.

In the picture is shown the Centro Laser mobile DIAL system.
The monostatic system consists of a transmitter and a receiver: the transmitter is a tunable (700-900nm) Ti:Sapphire laser, Nd:YAG pumped, with second and third armonic generation, working at 10Hz, pulse duration of 10nsec and energy up to 100mJ at 800nm.
The Ti:Sapphire configuration consists of an oscillator and a double-step amplifier longitudinally pumped.
The laser system emits also in the UV and visible regions (250-480nm) by mixing process in BBO crystals mounted on a galvanometer with a Nd-YAG laser (SHG-Ti:Sapphire + Nd-YAG; Ti:Sapphire + Nd-YAG) (see Experimental Set-up).

The main pollutans analyzed are NO₂ (MDC 80 ppb), SO₂ (MDC 20 ppb), benzene (MDC 10 ppb), toluene (MDC 20 ppb) and ozone (MDC 165 ppb).
Moreover it is possible to perform DIAL measurements of water vapor profile concentration by mean the fundamental of Ti:Sapphire laser.

Now we are up-grading the system to measure linear depolarization ratio to discriminate between ice crystal and liquid water content inside clouds and fogs.
Thermodynamic phase of clouds and fogs together with water vapor content into the atmosphere are the most important parameters to understand the climate change and the weather forecast for meteorological applications.