... . 2,Measure laser gain in the intracavity. F-HX1020 He-Ne Laser and Laser ResonanceExperiment contents and related subjects: 1. ... self-collimation method to adjust a semi-internal cavity He-Ne laser to meet the staring conditions for oscillation and ... laser, semi-internal cavity He-Ne laser, beam expander mirror, two-dimensional adjustable mold piece frame, laser power indicator, gain measuring annex ...