# Helium Neon Laser Wavelength
## 介紹
The helium neon (He-Ne) laser is a type of gas laser that emits red light. This laser is widely used in various applications, including barcode scanners, alignment devices, and scientific research. One of the key characteristics of the He-Ne laser is its specific wavelength of light.
## What is Wavelength?
Wavelength refers to the distance between two consecutive peaks or troughs of a wave. It is commonly denoted by the Greek letter lambda (λ) and is measured in meters (米). In the case of light, wavelength determines its color. Different colors of light have different wavelengths.
## Helium Neon Laser Wavelength
The wavelength of a He-Ne laser is approximately 632.8 nanometers (奈米) or 0.6328 micrometers (μm). This falls within the visible spectrum of light and appears as a red color. The specific wavelength of the He-Ne laser is determined by the energy levels of the excited helium and neon atoms within the laser tube.
## Energy Levels and Emission of Light
When an electric current is passed through the He-Ne laser tube, it excites the helium atoms to higher energy levels. These excited helium atoms then collide with neon atoms, transferring their energy. As a result, the neon atoms become excited and reach higher energy levels as well. When the neon atoms return to their ground state, they release energy in the form of light.
## Neon Emission Spectrum
The specific wavelength emitted by the He-Ne laser corresponds to a transition between the energy levels of the neon atoms. This transition is known as the 632.8 nm transition, and it produces red light. The energy difference between the excited and ground states of the neon atoms determines this wavelength. This energy difference precisely matches the energy of the emitted light.
## 應用領域
The specific wavelength of the He-Ne laser makes it suitable for various applications. In barcode scanners, the laser is used to scan and read barcodes. The red light emitted by the laser reflects off the barcode, and a sensor detects the changes in light intensity, translating them into data.
另外, the He-Ne laser’s wavelength is useful in alignment devices such as laser levels and optical instruments. The visible red light makes it easy to align objects accurately. Furthermore, in scientific research, the He-Ne laser is utilized in interferometry and holography due to its coherence and stability.
## 結論
The helium neon laser’s wavelength of 632.8 nm provides it with a distinct red color. This specific wavelength is determined by the energy levels and transitions of the excited helium and neon atoms within the laser tube. The He-Ne laser’s wavelength finds applications in barcode scanners, alignment devices, and scientific research, showcasing its versatility and importance in various fields.
