WAVELENGTH AND BEAM DIVERGENCE: INSIGHTS FROM SEMICONDUCTOR AND HELIUM-NEON LASERS
Abstract
The term "laser" stands for "light amplification by stimulated emission of radiation," representing the first device capable of amplifying light waves themselves. Laser light exhibits spatially coherent, narrow, low-divergence beams when its photons have identical frequency, phase, and direction, making it highly coherent. Due to their impact on basic research and various technological applications, lasers hold significant importance in the fields of science and technology. They find widespread use in consumer goods, music players, laser printers, product identification scanners, and industrial applications like metal cutting, welding, hole drilling, and marking, along with medical surgeries and scientific research.
Laser light covers a broad spectrum, ranging from red to violet and beyond the conventional limits of the optical spectrum. Its unique characteristics include coherence, directionality, monochromaticity, and high intensity, which enable highly focused beams and increased intensity. The power and wavelength of laser light are inversely related, leading to different propagation velocities and temporal pulse lengths in fibers.
This study primarily focuses on two types of lasers: semiconductor lasers and helium-neon lasers. Semiconductor lasers are electrically pumped and operate differently by merging two materials, leading to laser action through interference. They find applications in long-distance communication, compact disk players, high-speed printing, free-space communication, pump sources for other solid-state lasers, laser pointers, and medical applications. Semiconductor lasers offer high directionality due to their convergent nature.
On the other hand, helium-neon lasers were among the first developed and remain widely used due to their trouble-free operation and long lifetimes. Operating in a low-pressure mixture of helium and neon gases, these lasers have a common wavelength of 632.8nm, falling within the red portion of the spectrum.
In this study, we investigate the beam divergence angle versus wavelength of both types of lasers to determine which one exhibits higher directionality. The theoretical explanation suggests that semiconductor lasers are more directional than helium-neon lasers. This research aims to experimentally verify this claim and shed light on the directional properties of these lasers, contributing to our understanding of their potential applications and performance
