# Understanding Laser Wavelengths: A Beginner's Guide

• Freakyfemto
However, other factors such as the pulse modulator or amplifier used in the laser can also affect the peak lasing wavelength. In summary, the peak fluorescence and lasing wavelengths of a Ti:Sapphire laser are determined by the active medium and cavity length, but other factors such as the pulse modulator can also play a role.
Freakyfemto
Homework Statement
I was presented with the following problem during my laser course:

What is the peak lasing wavelength (and FWHM value) of a Ti:Saphire laser whos florescence spectrum has a peak wavelength of 800nm and a FWHM of 100 nm?
Relevant Equations
FWHM (lasing) = ?
Lambda (lasing) = ?
I don't know even where to start. In my reasoning peak florescence wavelength should be equal to its peak lasing wavelength. Is it something to do with pulse modulator (amplifier) that is used in Ti:Sapphire lasers? Or cavity length ? (But we were not given any cavity lengths).

Any help would be appreciated.

The peak fluorescence wavelength of a Ti:Sapphire laser is determined by its active medium, which is titanium-doped sapphire. This active medium has an absorption and emission spectrum that determines the peak fluorescence wavelength. The peak lasing wavelength of a Ti:Sapphire laser is determined by the cavity length and the gain medium, which includes the same titanium-doped sapphire active medium. The cavity length affects the resonant frequency of the laser, while the gain medium (which includes the titanium-doped sapphire) affects the amplitude of the laser emission. If the cavity length and the gain medium are matched correctly, then the peak lasing wavelength should be equal to the peak fluorescence wavelength of the titanium-doped sapphire.

## 1. What is a laser wavelength?

A laser wavelength refers to the distance between the peak of one wave of light to the peak of the next wave of light, measured in nanometers (nm). It is a characteristic of the specific type of laser being used and determines the color and properties of the laser beam.

## 2. How does the wavelength of a laser affect its properties?

The wavelength of a laser has a direct impact on its properties, such as its color, coherence, and diffraction. Shorter wavelengths, such as ultraviolet and blue, have higher energy and are more focused, while longer wavelengths, such as infrared, have lower energy and are more spread out.

## 3. What is the relationship between laser wavelength and material absorption?

The relationship between laser wavelength and material absorption is crucial in determining the effectiveness of a laser for a specific application. Different materials absorb different wavelengths of light, so the laser must have a wavelength that matches the material's absorption spectrum for optimal results.

## 4. How do lasers with different wavelengths interact with matter?

Lasers with different wavelengths interact with matter in different ways. Shorter wavelengths, such as X-rays, can penetrate deeper into materials, while longer wavelengths, such as infrared, are better at heating and cutting through materials.

## 5. How can I determine the wavelength of a laser?

The wavelength of a laser can be determined using a variety of methods, such as using a diffraction grating to split the laser beam into its component colors or using a spectrometer to measure the light emitted by the laser. Laser manufacturers also provide information on the specific wavelength of their lasers.

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