  There is a present-day need of optimization of the combustion processes and
catalytic efficiency for minimization of emission of pollutants, which can be
possible by analyzing the temperature and combustion products distribution in
the combustion processes internally. This paper discusses the feasibility of
simultaneous 2-D tomographic imaging of temperature and concentrations of
CO$_2$ and H$_2$O by scanning a single narrowband laser. The choice of
spectroscopic lines of H$_2$O for two-tone temperature measurement is discussed
around the wavelength range of 2000 nm. This region is selected as both H$_2$O
and CO$_2$ spectral lines have sufficient intensity levels. The pair of
wavenumbers (5005.53 and 5003.3 cm$^{-1}$) is found the best of all for
temperature and H$_2$O concentration distribution and 5004.36 cm$^{-1}$ is
chosen for CO$_2$. To establish the efficacy of different reconstruction
algorithms, the phantoms of bimodal and concentric temperature distribution
with uniform concentration were tried with four reconstruction techniques.
Impressive reconstructions were achieved for distribution of temperature and
concentrations of H$_2$O and CO$_2$ for same types of phantoms using Filtered
Landweber and Tikhonov regularization methods for 5005.53 and 5003.3 cm$^{-1}$.
Initially the imaging was tried using both fanbeam and discrete irregular beam
array with 100 and 31 beams respectively. Instead of less number of beams, the
later one also shows very promising result.
