Lecture
This lecture discusses the principles of reflecting a pulsed laser beam, using total internal reflection, and measuring the Earth-Moon distance with high precision. It covers topics such as beam divergence, turbulence effects, attenuation, and the challenges of dust and meteorites. The lecture also explores Gaussian beams, war-Gaussian beams, and apodized Gaussian beams, as well as the focusing of Gaussian beams by lenses.