Study Of TEA CO₂ Laser Frequency Locking And Rapidly Tuning

A frequency stabilized TEA CO₂ laser is the ideal light source for heterodyne differential absorption lidar (DIAL). When using a single laser as emission source for DIAL, the laser is required to emit two beams of different wavelengths in the atmosphere "frozen" time (≤10ms) .Therefore, in order to let the lidar system work stably and efficiently, a reliable and fast tuning system and frequency stabilizing methods are definitely required. In view of this condition, technologies to realize frequency locking and rapidly tuning have been investigated in this dissertation.In theory, the mathematic model of injected locking is analyzed, providing theoretical support for the experimental program. Through coupling the field equations and the rate equation, characteristics of the laser output under different injection conditions are discussed.In experiment, an inject locking scheme based on taking the pulse setup time as the criteria for judgment, an inject locking scheme is proposed. Meanwhile, a servo control system is designed and used, succeeding in locking the frequency of pulse TEA CO₂ laser to the seeding frequency which is stabled. To measure and display the pulse set-up time, the laser trigger system is designed.Based on the above achievements, a rapidly tuning method is successfully used, resolving the problem that it is difficult to ensure the frequency stable under the condition of fast tuning. While achieving fast tuning, the injection locking and twist-mode means is used to achieve the 10R(16) and 9P(40) single longitudinal mode. The fast tuning device need not to move the grating or any mechanical device, so it is easy to keep stable and laid good foundation for a single laser as light source of DIAL.