LIDAR SPRECTROSCOPY INSTRUMENT (LISSI): AN
INFRASTRUCTURE FACILITY FOR CHEMICAL AEROSOL
PROFILING AT THE UNIVERSITY OF HERTFORDSHIRE
Matthias Tesche1,*, Boyan Tatarov1, Youngmin Noh2 and Detlef Müller1,2
1University of Hertfordshire, Hatfield, United Kingdom, ∗m.tesche@herts.ac.uk
2Gwangju Institute of Science and Technology, Gwangju, South Korea
ABSTRACT
The lidar development at the University of Hert-
fordshire explores the feasibility of using Raman
backscattering for chemical aerosol profiling. This
paper provides an overview of the new facility. A
high-power Nd:YAG/OPO setup is used to excite
Raman backscattering at a wide range of wave-
lengths. The receiver combines a spectrometer with
a 32-channel detector or an ICCD camera to resolve
Raman signals of various chemical compounds.
The new facility will open new avenues for chemical
profiling of aerosol pollution from measurements of
Raman scattering by selected chemical compounds,
provide data that allow to close the gap between op-
tical and microphysical aerosol profiling with lidar
and enables connecting lidar measurements to pa-
rameters used in atmospheric modelling.
1 INTRODUCTION
Conventional Raman or high spectral resolution li-
dar is used for deriving profiles of aerosol optical
properties and, if proper input data are provided,
retrieving aerosol microphysical properties through
inversion techniques. The lidar development at the
University of Hertfordshire (UH) is centred on ex-
ploring the feasibility of using Raman backscatter
of various target species to obtain mass concentra-
tion profiles of selected chemical compounds. This
marks the logical next step in aerosol profiling with
lidar and will allow for defining aerosol types ac-
cording to their chemical composition rather than
optical properties. Ultimately, this will unify the
treatment of aerosol types in lidar remote sens-
ing with that of in-situ measurements and atmo-
spheric modelling. The feasibility of the underlying
methodology has been proven for measurements of
Raman backscattering at silicone dioxide molecules
within Asian dust layers [1, 2, 3].
2 OBJECTIVES
The lidar spectroscopy instrument (LiSsI) will en-
able profiling of trace gases, chemical components
in particles, and bio-aerosols in atmospheric aerosol
pollution through the combination of different non-
linear spectroscopy techniques (photoluminescence,
fluorescence, Raman and coherent anti-Stokes Ra-
man spectroscopy) in a single measurement plat-
form. The work at UH includes (1) the develop-
ment of an end-to-end simulator that allows us to
model the processes of inelastic photoluminescence
and Raman scattering by aerosol particles and gases
in the context of lidar remote sensing, (2) the iden-
tification of the luminescence and Raman scatter-
ing characteristics for a set of key aerosol types
and gases (of natural and anthropogenic origin) by
means of laboratory experiments, (3) test measure-
ments and case studies as a proof of concept of the
technique under laboratory conditions, and (4) the
characterisation and development of a mobile pro-
totype inelastic lidar spectrometer receiver for field
deployment at established lidar sites.
3 LABORATORY SETUP
Figure 1 presents a sketch of the setup of the LiSsI
facility. The main components are a high power
Nd:YAG laser (Continuum Powerlite Furie LD), an
Optical Parametric Oscillator (Horizon OPO), a mo-
torised beam combiner, a multiwavelength depolar-
isation Raman lidar receiver, a Horiba 1250M spec-
trometer that can be used with an intensified CCD
camera (ICCD, Princeton Instruments PI-MAX4
1024i-HBf) or a 32-channel Licel PMT (32PMT),
an Olympus BX51TRF-6 Raman/flourescence mi-
croscope, and several custom-made gas chambers.
An overview of the properties of the transmitter is
provided in Table 1. The combination of a high-
power Nd:YAG laser and an Optical Parametric Os-
EPJ Web of Conferences 176, 01008 (2018) https://doi.org/10.1051/epjconf/201817601008
ILRC 28
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution 
License 4.0 (http://creativecommons.org/licenses/by/4.0/).
192-400 nm
400-2750 nm
355, 532, 1064 nm
P
M
T
Nd:YAG
laser
OPO
Telescope
MBC
Olympus 
BX51TRF-6
microscope
gas
chambers
ICCD/32PMT
Horiba
1250Mlidar receiver and data acquisition,
signal selection for
spectrometric measurements
Figure 1: Sketch of the laboratory setup including a
high-power Nd:YAG laser, a motorised beam combiner
(MBC), an Optical Parametric Oscillator (OPO), an
advanced lidar receiver, a spectrometer, an intensified
CCD camera (ICCD), a 32-channel Licel PMT
(32PMT), a Raman/flourescence microscope, and
several gas chambers.
cillator allows for exciting Raman backscatter for a
wide range of excitation wavelengths. The novel li-
dar receiver setup has been designed and simulated
using ZEMAX and will combine the spectral res-
olution of spectrometers with a 32-channel detec-
tor to resolve Raman signals of a variety of chem-
ical compounds. An overview of the configuration
and properties of the receiver and data acquisition
is provided in Table 2. Aerosol chambers will en-
able measurements of a range of chemical species
to test the methodology for known compounds and
to assess the respective detection limit with respect
to applied laser power and resolvable particle con-
centrations. A Raman microscope will be used to
measure the Raman scattering cross-sections of the
selected target species—information that is needed
to transform the detected signals into mass concen-
trations.
Table 1: Properties of the transmitter.
Continuum Powerlite Furie LD
Laser type Nd:YAG, injection seeded
Wavelength and 7500mJ @1064 nm
pulse energy 5000mJ @532 nmnm
2500mJ @355 nm
Beam divergence 0.5mrad, 0.1mrad after
5-fold beam expansion
Repetition rate 10Hz
Linewidth <0.003 cm−1
Pulse duration <15 ns
Horizon Optical Parametric Oscillator
Pumping wavelength 355 nm
Wavelength and from 192 to 2750 nm
pulse energy scanning step 0.01 nm
120mJ @400 nm
60mJ @600 nm
25mJ @300 nm
Beam divergence <2mrad (both axes)
Repetition rate 10Hz
Linewidth 2-6 cm−1, injection seeded
Pulse duration <15 ns
The aim of the facility is to carry out precise inelas-
tic spectroscopy experiments that target measure-
ments of photoluminescence, fluorescence, and Ra-
man spectra of aerosol and gas samples. These mea-
surements will include the identification of spec-
tra, absolute values of fluorescence, and Raman
cross-sections that are currently poorly known or
unknown.
4 APPLICATIONS IN LIDAR AND SPEC-
TROSCOPY
The LiSsI facility has been designed to allow for
comprehensive laboratory experiments as well as for
atmospheric observations. The laser beam can be
released into the atmosphere through a hatch in the
roof of the laboratory. The backscattered light is
collected with a 14-inch Schmidt-Cassegrain tele-
scope and guided to the different components of
the receiver (Table 2). Depending on the setup
of the experiment, LiSsI can be used as multi-
wavelength elastic backscatter lidar for measure-
ments of aerosols and temperature from the tropo-
sphere to the mesosphere, as multi-channel spectro-
scopic Raman lidar (using Stokes and anti-Stokes,
rotational, and rotational-vibrational Raman scat-
tering), multi-channel spectroscopic photolumines-
cence/fluorescence lidar, high spectral resolution li-
2
EPJ Web of Conferences 176, 01008 (2018) https://doi.org/10.1051/epjconf/201817601008
ILRC 28
192-400 nm
400-2750 nm
355, 532, 1064 nm
P
M
T
Nd:YAG
laser
OPO
Telescope
MBC
Olympus 
BX51TRF-6
microscope
gas
chambers
ICCD/32PMT
Horiba
1250Mlidar receiver and data acquisition,
signal selection for
spectrometric measurements
Figure 1: Sketch of the laboratory setup including a
high-power Nd:YAG laser, a motorised beam combiner
(MBC), an Optical Parametric Oscillator (OPO), an
advanced lidar receiver, a spectrometer, an intensified
CCD camera (ICCD), a 32-channel Licel PMT
(32PMT), a Raman/flourescence microscope, and
several gas chambers.
cillator allows for exciting Raman backscatter for a
wide range of excitation wavelengths. The novel li-
dar receiver setup has been designed and simulated
using ZEMAX and will combine the spectral res-
olution of spectrometers with a 32-channel detec-
tor to resolve Raman signals of a variety of chem-
ical compounds. An overview of the configuration
and properties of the receiver and data acquisition
is provided in Table 2. Aerosol chambers will en-
able measurements of a range of chemical species
to test the methodology for known compounds and
to assess the respective detection limit with respect
to applied laser power and resolvable particle con-
centrations. A Raman microscope will be used to
measure the Raman scattering cross-sections of the
selected target species—information that is needed
to transform the detected signals into mass concen-
trations.
Table 1: Properties of the transmitter.
Continuum Powerlite Furie LD
Laser type Nd:YAG, injection seeded
Wavelength and 7500mJ @1064 nm
pulse energy 5000mJ @532 nmnm
2500mJ @355 nm
Beam divergence 0.5mrad, 0.1mrad after
5-fold beam expansion
Repetition rate 10Hz
Linewidth <0.003 cm−1
Pulse duration <15 ns
Horizon Optical Parametric Oscillator
Pumping wavelength 355 nm
Wavelength and from 192 to 2750 nm
pulse energy scanning step 0.01 nm
120mJ @400 nm
60mJ @600 nm
25mJ @300 nm
Beam divergence <2mrad (both axes)
Repetition rate 10Hz
Linewidth 2-6 cm−1, injection seeded
Pulse duration <15 ns
The aim of the facility is to carry out precise inelas-
tic spectroscopy experiments that target measure-
ments of photoluminescence, fluorescence, and Ra-
man spectra of aerosol and gas samples. These mea-
surements will include the identification of spec-
tra, absolute values of fluorescence, and Raman
cross-sections that are currently poorly known or
unknown.
4 APPLICATIONS IN LIDAR AND SPEC-
TROSCOPY
The LiSsI facility has been designed to allow for
comprehensive laboratory experiments as well as for
atmospheric observations. The laser beam can be
released into the atmosphere through a hatch in the
roof of the laboratory. The backscattered light is
collected with a 14-inch Schmidt-Cassegrain tele-
scope and guided to the different components of
the receiver (Table 2). Depending on the setup
of the experiment, LiSsI can be used as multi-
wavelength elastic backscatter lidar for measure-
ments of aerosols and temperature from the tropo-
sphere to the mesosphere, as multi-channel spectro-
scopic Raman lidar (using Stokes and anti-Stokes,
rotational, and rotational-vibrational Raman scat-
tering), multi-channel spectroscopic photolumines-
cence/fluorescence lidar, high spectral resolution li-
2
Table 2: Properties of the receiver and data acquisition system.
Schmidt-Cassegrain telescope
Focal length 3910mm (14 inch)
Field of view 0.5-4.0mrad (variable)
HORIBA 1250M Research Spectrometer
Focal length 1.25m
Aperture F/9
Spectral range 0-1500 nm mechanical range (1200 g/mm grating)
Grating size 110mm × 110mm
Dispersion @500 nm 0.65 nm/mm
Accuracy ±0.15 nm
Repeatability ±0.005 nm
Gratings 2400 g/mm blaze 250 nm, max resolution 0.003 nm
and resolutions 1800 g/mm blaze 400 nm, max resolution 0.004 nm
@313.183 nm 1200 g/mm blaze 330 nm, max resolution 0.006 nm
600 g/mm blaze 500 nm, max resolution 0.012 nm
Detection
Mie and Rayleigh 355 nm, PMT HV-R9880U-20, bandwidth 1.3 nm
scattering 532 nm, PMT HV-R9880U-20, bandwidth 1.3 nm
1064 nm, APD InGaAs50, bandwidth 4 nm
Spectroscopic 1 Hamamatsu H7260-20, 0.8mm×7mm×32 anodes
Licel SP32-20 spectral response 300-920 nm
Spectroscopic 2 1024×1024 imaging pixels; 12.8 µm×12.8 µm pixels
Princeton Instruments Gen III filmless intensifier
PI-MAX4 Sensitive range 290-710 nm
ICCD camera QE>20% in range 355-700 nm; QE>40% in range 410-640 nm
Data acquisition system
Mie and Rayleigh Licel transient recorders, 16 bit, 20MHz A/D converters and photon-counters
scattering maximum count rate 250MHz, variable range resolution
Multi-anode PMT Single-photon counting system, maximum count rate 100MHz, 50 ns resolution
ICCD Digitization 16 bit, 32MHz, minimum gate width 2 ns
dar (HSRL), polarization lidar, or infrared absorp-
tion and differential absorption lidar (DIAL).
In addition, LiSsI opens possibilities for a wide
range of applications in spectroscopy: general
spectroscopy (attenuation, transmission, and re-
flectance spectroscopy), high-spectral resolution
spectroscopy, Stokes and anti-Stokes Raman spec-
troscopy of gas and solid material including ap-
plications involving a microscope, fluorescence
spectroscopy of gas and solid material including
microscope applications, laser-induced breakdown
spectroscopy, coherent-anti-Stokes Raman spec-
troscopy, time-resolved spectroscopy, infrared gas
analysis and materials processing.
5 FIRST RESULTS
The LiSsI laser has been installed in September
2017. Figure 2 shows one of the first measure-
1E6
Figure 2: First measurement at 532 nm on 22 September
2017 (black) together with a molecular (red) and a
temperature (blue) profile from a sounding launched at
Nottingham at 0000 UTC on 22 September 2017.
ments performed between 1026 and 1330 UTC on
22 September 2017 using only a 532-nm elastic
channel and a laser power of about 30mJ. The ana-
log counting signal is shown in the figure. Despite
the low laser power, a rather small telescope and
3
EPJ Web of Conferences 176, 01008 (2018) https://doi.org/10.1051/epjconf/201817601008
ILRC 28
      




















Figure 3: Time-height display (left) and average profile (right) of the range-corrected signed at 532 nm detected
during a measurement between 1644 and 2010 UTC on 28 September 2017 with a temporal resolution of one minute.
observations being performed during daytime, rea-
sonable signals can be obtained up to a height of
20 km. Aerosol can be seen in the lowermost 4 km
as well as in layers at 7, 11, 14, 15, and 16 km
height. The temperature profile of a radiosonde
launched at Nottingham (about 150 km north of Hat-
field) shows the tropospause at about 10 km height,
putting the upper aerosol layers—likely originating
from pyro-cumulonimbus events in Canada several
weeks earlier—well within the stratosphere.
Figure 3 presents data from the first nighttime mea-
surement performed with LiSsI. The configuration
has been the same as during the measurements pre-
sented in Figure 2. Cirrus clouds are clearly visible
between 6.5 and 13.0 km. The stratospheric aerosol
layer from Figure 2 is still present between 17 and
18 km height.
6 NEXT MILESTONES
The coming milestones in developing the LiSsI fa-
cility are aligned with increasing the complexity of
the optical setup. After the initial test measurements
(Figure 2), we intend to perform atmospheric mea-
surements of elastically and inelastically backscat-
tered light at the different laser wavelength using
full power. After that, the spectrometer will be inte-
grated into the lidar receiver to allow for multispec-
tral measurements in the atmosphere and using the
gas and aerosol chambers in the laboratory.
ACKNOWLEDGEMENTS
The LiSsI facility has been funded by the Uni-
versity of Hertfordshire through capital investment.
Boyan Tatarov is supported by a Marie Skłodowska-
Curie Action Fellowship of the European Commis-
sion (CAPABLE, H2020-MSCA-IF-2015).
References
[1] Tatarov, B. and Sugimoto, N., 2005: Estimation
of quartz concentration in the tropospheric mineral
aerosols using combined Raman and high spectral
resolution lidars, Opt. Lett. 30, 3407-3409.
[2] Müller et al., 2010: Mineral quartz concentration
measurements of mixed mineral dust/urban haze
pollution plumes over Korea with multiwavelength
aerosol Raman-quartz lidar,Geophys. Res. Lett. 37,
2010GL044633.
[3] Tatarov et al., 2011: Lidar measurements of Ra-
man scattering at ultraviolet wavelength from min-
eral dust over East Asia, Opt. Expr. 19, 1569-1581.
4
EPJ Web of Conferences 176, 01008 (2018) https://doi.org/10.1051/epjconf/201817601008
ILRC 28