Punta Arenas Data Sheet

The multiwavelength raman Lidar is operational in the Atmospheric Research Laboratory site since September 2016. It uses a Continumm Surelite II Nd-YAG laser at 1064 nm, 532 nm and 355 nm with total energy for all wavelength at exit port of 590 mJ and 10 Hz repetition rate. Laser beam is not expanded with a laser divergence around 0.5 mrad. The optical system uses a coaxial configuration setup pointing 5 degrees out of the zenith. The Newtonian telescope’s mirror has 203 mm diameter. Focal length is 1000 mm resulting in a f/5 system. An iris is used at the focal plane which gives a full overlap around 200 m.

No fiber optics are used and light passing through the iris goes directly in the optical detection box. Beam splitter, polarizing bandpass filters and interference filters separate the signals. Elastics back scattered signal 1064 nm are collected in a Avalanche photodiode from Licel. Elastic signals from 532 nm and 355 nm (cross and co polarized) and the inelastic signals due to the raman cross-section of N2 (387 nm and 607 nm), H2O (408 nm) are collected in different photo-multiplier-tubes. Signals from 355 and 532 nm (cross and co polarized) are recorded in analog and photon-count modes simultaneously, while 607 nm and 408 nm only in photon counting mode. A neutral density filter is used to attenuate the elastic signal avoiding saturation, and a good signal to noise ratio (S/N) is found around 15 km depending on the atmospheric conditions. The N2 channel, 1-min average signals have good S/N up to 10 km but only during night time. For the H2O channel, 1-min average signals have good S/N only up to 4 km during night time.

Laser typeSolid stale Nd:YAG laser (Surelite II 10 - Continuum)
Wavelength1064 nm, 532 nm, 355nm
Pulse energy690 mJ @ 1064nm
Repetition10 Hz
Divergence0.5 mrad
Pulse duration4 - 7 nm
Expandernot used
Rain proofyes
Diameter = 20 cm
Focal length = 1 m
DetectorsPMT 355o - Hamamatsu H10721-110
PMT 355p - Hamamatsu H10721-110
PMT 387r - Hamamatsu H10721-110
PMT 408r - Hamamatsu H10721-110
PMT 532o - Hamamatsu H10721-20
PMT 532p - Hamamatsu H10721-20
PMT 607r - Hamamatsu H10721-20
APD 1064 - LICEL APD 3.0
Data acquisitionSpecification
Detection range (approximate)350 m - 13 km
Range resolution7,5 m
Elastic channelsTransient recorder. 12 Bit, 20Ms/s. (TR20-12bit-LICEL)
Raman channelsTransient recorder. 12 Bit, 20Ms/s. (TR20-12bit-LICEL)