Lecture
This lecture introduces beam optics, covering ray optics, wave optics, beams, diffraction, Fourier optics, principles of lasers, microscopy, manipulation, spectroscopy, X-rays, diffraction, imaging, and spectroscopy. Special cases like the Fresnel approximation for spherical waves are discussed, along with Gaussian beams and their solutions for the Helmholtz equation. The Gaussian beam, named after Carl Friedrich Gauss, is explored in depth, including its intensity distribution and depth of focus. The lecture also delves into the concepts of phase and amplitude separation, complex envelope solutions, and the Gaussian beam's complex envelope. Additionally, the lecture touches on the concepts of beam waist, intensity distribution, and curvature of wavefronts.