Difrakci

Difrakci is the phenomenon by which waves bend and spread as they encounter obstacles or pass through openings, producing characteristic interference patterns. It occurs with all wave types, including light, sound, and matter waves, and underpins many optical and wave‑based technologies. Diffraction can be observed when a wave encounters a slit, an edge, or a lattice of openings, leading to regions of constructive and destructive interference that shape the observed intensity distribution.

The phenomenon is commonly analyzed using the Huygens–Fresnel principle, which treats every point on a wavefront as a secondary source. In practice, simple models include single-slit diffraction, double-slit interference, and diffraction gratings. For a single slit of width a, the intensity follows I(θ) ∝ (sin β / β)^2 with β = (π a sin θ)/λ. For a diffraction grating with spacing d, principal maxima appear at d sin θ = mλ. In crystals, diffraction of X‑rays is described by Bragg’s law, 2d sin θ = nλ, which reveals crystal structure.

Historically, diffraction experiments in the early 19th century demonstrated wave nature of light (Young, Fresnel), while in the 20th century, wave aspects of matter were confirmed through electron diffraction (Davisson–Germer) and X‑ray diffraction methods (Bragg, Laue). Today, diffraction limits the resolution of imaging systems (Airy patterns), enables precise material characterization (crystallography), and is foundational in optics, acoustics, and quantum mechanics.

Common applications include optical instruments, spectroscopy, fiber optics, electron and X‑ray crystallography, and the analysis of wave propagation in various media. Diffraction remains a central concept in physics, linking wave behavior to observable patterns across disciplines.