The invention discloses a
laser absorption spectrum
system for
random noise modulation, which relates to the technical field of
trace gas detection of absorption spectrum technology, and is characterized in that a
signal generation module generates
random noise and low-frequency triangular
waves with different powers, different bandwidths and different distribution characteristics;
laser generated by the
light source module is modulated through
random noise and low-frequency triangular
waves;
laser generated by the
light source module enters the
light flux cell, namely the annular optical multi-pass
cell and reciprocates; the
signal processing module receives emergent light of the
light flux cell and generates a first feedback
signal and a second feedback signal according to the emergent light of the
light flux cell; the signal generation module adjusts random
noise according to the first feedback signal; the
light source module adjusts the laser incident angle according to the second feedback signal. According to the invention, random
noise modulation is carried out on the light source, interference
noise of the
system is suppressed, and under the condition that the physical size and the structure of the light flux cell are ensured, the distribution number of mirror light spots is increased, and the effective absorption
optical path of gas in the light flux cell is improved, so that high-sensitivity detection of
trace gas is realized.