Experimental Studies On Injection Locking Of TEA CO₂Laser By A Continuous-wave Signal

THz wave has the characteristic of good perspective, high resolution and excellentsecurity and it is widely used in biological technology, aerospace, materials science, etc. It isvery effective to pump organic molecules with a high-power Single-longitudinal-mode TEACO₂laser in obtaining coherent THz radiation, and injection locking is the best method torealize such a kind of pumping source.Full investigation in the development of injection locking of TEA CO₂laser both homeand abroad was gave, the features of power and instantaneous frequency of laser pulse inthree distinct regions of operation, which included spontaneous oscillation, mode selection,frequency locking, when there was external injected signal in the TEA CO₂laser wassummarized, and the crucial factors of injection locking was discussed.In cavity length control, the digital acquisition card was determined as the corecontroller based on the development results of an earlier control system; the experimentalplatform was built and software programs was coded; Under the static condition, the cavitylength was adjust by changing the voltage to a piezoelectric ceramics driver, the search ofoptimal operating point was achieved and the cavity frequency resonance with injectedsignal was realized.In experimental studies, the injection locking of unstable resonator TEA CO₂with bothlower power SLM （single-longitudinal-mode） and higher power continuous-wave signalwas completed. Due to electromagnetic interference, low isolation degree and itsmulti-branch characteristics in free running, the injected signal couldn’t effectively suppressthe oscillation of other branches, The TEA CO₂laser was still characterized by multi-branchoscillation, however, the injected branch has realized a in high possibility; in theinjection-locking of grating-tuned TEA CO₂laser, single-longitudinal-mode output pulse hasrealized in a high possibility. To get better results, it is necessary to optimize the design ofelectromagnetic compatibility to improved anti-jamming measures and improve the isolationdegree.