Can you name three properties of a laser beam?

Answer 1

There are more than 3.
1. Line width (MHz) is a measure of how monochromatic laser radiation is. A laser line usually has a Gaussian frequency profile. The width is taken as the FWHM. The line width from a diode laser is much greater than the line width from a gas laser.
2. Mode spacing. (MHz) This is determined by the optical length of the laser cavity and the gain profile. Lasers generally lase at more than one frequency.
3. Non-lasing lines. Lasers radiate small amounts of radiation from transitions that are not amplified.
4. Mode structure. The two dimensional distribution of radiation within a laser beam. A circular beam is the lowest mode TEM 00.
5. Beam divergence (milliradians) is a measure of how quickly the laser beam spreads out.
6. Beam waist. This is the minimum beam diameter. Together with the beam divergence, these variables determine the beam diameter at any distance.
7. Polarization (linear/circular), degree of polarization.
8. Intensity (W). The power transmitted by the beam.
9. Coherence: the coherence length is a measure of how long a wave train is in phase and can interfere with itself.

Answer 2

Laser light has the following properties:

1. The light released is monochromatic. It contains one specific wavelength of light (one specific color). The wavelength of light is determined by the amount of energy released when the electron drops to a lower orbit.

2. The light released is coherent. It is “organized” -- each photon moves in step with the others. This means that all of the photons have wave fronts that launch in unison.

3. The light is very directional. A laser light has a very tight beam and is very strong and concentrated. A flashlight, on the other hand, releases light in many directions, and the light is very weak and diffuse.