Backgroundsignal
The LIDAR efficiency is highly dependent on the background radiation due to the natural atmospheric or other sources of light. Collecting the “right photon” among a tremendous amount of light is not easy. That induces a large difference in the performances of most of the systems during daylight. Leosphere’s engineers managed to solve this problem by applying a multiple-step filtering method reduces the background signal down to 1%. As a result, EASY LIDAR provides data of almost the same accuracy during daytime and night time.

Overlapfactor
Unlike many LIDAR systems that are totally or partially blind from several hundreds meters to more than 1km of observation range, EZ LIDARs’ full vision is reached at 150m (the emitted laser beam is in the full field of view of the optical collector) and the first point measurement at 15m. This optical scheme is superior to many systems  that need to widely spread the laser beam to obtain the same overlap.

Eyesafety / Power Equation
ALS300 emits the UV laser pulses into the atmosphere, as the UV light is known as the best wavelength for molecular diffusion detection. This choice of wavelength, inspired by the latest space-based LIDAR development, respects the EN-60801 safety requirements, while offering a strong laser power and hence, provides high temporal resolution of the measurement even by daylight. It also allows an easy upgrade of the system. When it is time to work on received light (depolarization, raman filtering…) EZ LIDAR has enough power to keep matching your energy needs.

Raman Effect
Raman Effect is the inelastic scattering of a photon which creates or annihilates an optical phonon. When light is scattered from an atom or molecule, most photons are elastically scattered (Rayleigh scattering). The scattered photons have the same energy (frequency) and, therefore, wavelength, as the incident photons. However, a small fraction of light is scattered at optical frequencies different from the incident photons frequency. In a gas, Raman scattering can occur with a change in vibrational, rotational or electronic energy of a molecule (see energy level). Chemists are concerned primarily with the vibrational Raman effect.

Thanks to the energy shift we can detect for specific molecules returns, as Nitrogen at 387nm or H20 at 408nm, for 355nm emitted wavelength, using very narrow interferential filters and highly sensitive detection channels. From these measurements, We can retrieve for the mixing ratio in the troposphere and thus obtain a real humidity profile using temperature profiles.