An auto-aligning spectroscopy system, comprising: a launcher unit for directing a first laser beam from a first laser source and a second laser beam from a second laser source through a chamber, the chamber being adapted to contain a gas to be sampled and having a first window and a second window wherein the first laser beam is co-linear with the second laser beam; a receiver unit for being disposed at the opposite side of the chamber to the launcher unit and for receiving the first laser beam and the second laser beam passing through the first window and the second window of the chamber, wherein the receiver unit comprises: a first detector configured to determine an intensity of the first laser beam; a second detector configured to: generate at least two signals indicative of a first position of the second laser beam incident on the second detector, wherein the first position is different from a determined position corresponding to a base-line position of the launcher unit; generate at least one signal indicative of a power associated with the second laser beam; determine a deviation of the second laser beam from the determined position; a controller unit configured to: determine a power loss of the second laser beam based on the power associated with the second laser beam; compare the determined power loss of the second laser beam with a determined threshold value; identify a scattering of the second laser beam when the power loss of the second laser beam is less than the determined threshold value and there is no deviation of the second laser beam from the determined position; and a motorized stage configured to align the launcher unit to the base-line position when the power loss of the second laser beam is greater than the determined threshold value; with the controller unit being further adapted to determining an absorption power loss of the first laser beam based on the determined power loss of the second laser beam when the scattering of the second laser beam is identified; and to measuring a gas species in the chamber based on the determined absorption power loss of the first laser beam. a launcher unit for directing a first laser beam from a first laser source and a second laser beam from a second laser source through a chamber, the chamber being adapted to contain a gas to be sampled and having a first window and a second window wherein the first laser beam is co-linear with the second laser beam; a receiver unit for being disposed at the opposite side of the chamber to the launcher unit and for receiving the first laser beam and the second laser beam passing through the first window and the second window of the chamber, wherein the receiver unit comprises: a first detector configured to determine an intensity of the first laser beam; a second detector configured to: generate at least two signals indicative of a first position of the second laser beam incident on the second detector, wherein the first position is different from a determined position corresponding to a base-line position of the launcher unit; generate at least one signal indicative of a power associated with the second laser beam; determine a deviation of the second laser beam from the determined position; a first detector configured to determine an intensity of the first laser beam; a second detector configured to: generate at least two signals indicative of a first position of the second laser beam incident on the second detector, wherein the first position is different from a determined position corresponding to a base-line position of the launcher unit; generate at least one signal indicative of a power associated with the second laser beam; determine a deviation of the second laser beam from the determined position; generate at least two signals indicative of a first position of the second laser beam incident on the second detector, wherein the first position is different from a determined position corresponding to a base-line position of the launcher unit; generate at least one signal indicative of a power associated with the second laser beam; determine a deviation of the second laser beam from the determined position; a controller unit configured to: determine a power loss of the second laser beam based on the power associated with the second laser beam; compare the determined power loss of the second laser beam with a determined threshold value; identify a scattering of the second laser beam when the power loss of the second laser beam is less than the determined threshold value and there is no deviation of the second laser beam from the determined position; and determine a power loss of the second laser beam based on the power associated with the second laser beam; compare the determined power loss of the second laser beam with a determined threshold value; identify a scattering of the second laser beam when the power loss of the second laser beam is less than the determined threshold value and there is no deviation of the second laser beam from the determined position; and a motorized stage configured to align the launcher unit to the base-line position when the power loss of the second laser beam is greater than the determined threshold value; with the controller unit being further adapted to determining an absorption power loss of the first laser beam based on the determined power loss of the second laser beam when the scattering of the second laser beam is identified; and to measuring a gas species in the chamber based on the determined absorption power loss of the first laser beam.