Laser light wavelengths are generally measured in micrometers (μm) or nanometers (nm).
Understanding Laser Wavelength Measurements
Laser wavelengths refer to the range of electromagnetic radiation wavelengths where lasers operate. As stated in the reference, these are typically measured in micrometers (μm) or nanometers (nm). These units are used because laser wavelengths are incredibly small, falling within various spectral regions from the infrared to the visible and ultraviolet.
- Nanometer (nm): One nanometer is one billionth of a meter (10⁻⁹ m). This unit is commonly used for visible and ultraviolet light wavelengths, which are shorter.
- Micrometer (μm): One micrometer (also called a micron) is one millionth of a meter (10⁻⁶ m), or 1000 nanometers. This unit is often used for infrared wavelengths, which are longer.
Spectral Regions and Typical Units
Different types of lasers operate at different wavelengths, corresponding to specific parts of the electromagnetic spectrum. The choice of unit often depends on the region:
- Ultraviolet (UV): Typically measured in nanometers (e.g., excimer lasers at 193 nm or 248 nm).
- Visible Light: Always measured in nanometers (e.g., green lasers at 532 nm, red lasers at 635-670 nm). This is the portion of the spectrum our eyes can see, roughly from 400 nm (violet) to 700 nm (red).
- Infrared (IR): Often measured in both nanometers (for near-infrared) and micrometers (for mid and far-infrared).
- Near-Infrared: 700 nm to around 2500 nm (or 0.7 μm to 2.5 μm). Common examples include Nd:YAG lasers at 1064 nm (1.064 μm).
- Mid/Far-Infrared: Ranges up to hundreds of micrometers. CO₂ lasers, for instance, typically operate around 10.6 μm.
Understanding the specific wavelength is crucial for various applications, as different wavelengths interact with materials, tissues, or the atmosphere in distinct ways.
Examples of Laser Wavelengths and Units
Here's a simple illustration showing how units relate to spectral regions:
| Spectral Region | Typical Wavelength Range | Common Unit | Example Laser & Wavelength |
|---|---|---|---|
| Ultraviolet | 10 nm – 400 nm | Nanometer | ArF Excimer (193 nm) |
| Visible | 400 nm – 700 nm | Nanometer | Green DPSS (532 nm) |
| Near-Infrared | 700 nm – ~2.5 μm | Nanometer/Micrometer | Nd:YAG (1064 nm / 1.064 μm) |
| Mid-Infrared | ~2.5 μm – ~25 μm | Micrometer | CO₂ (10.6 μm) |
These units provide a convenient scale for describing the precise and often very short wavelengths of laser light.
