# Tag Info

4

The semiconductor lasers that are used to produce white light are powered by electricity, so that solves your problem. As lasers emit monochromatic light (1 single frequency or colour), they cannot be white. To get white laser light, you start with a blue laser. This blue light is directed at some phosphorescent material (a "phosphor") which, when activated ...

2

For gamma-ray wavelengths a much better alternative are Free Electron Lasers, since their gain medium is the Bestrahlung and synchrotron electron radiation inside the undulators. They also have the benefit of not being constrained to a nuclear energy state, and they can operate on a range of wavelengths

2

For two perfect laser sources without noise (infinite narrow linewidth) and of same amplitude, you could achieve this when both sources have the same frequency and same polarization. You need to control the length of one pathway to control the relative phase to $\phi_0=\pi$: $E=E_1+E_2=E_0 (sin(\omega t)+sin(\omega t+\phi_0))$ The problem in general will ...

2

I'll take a stab at this, although I am not an expert in the laser fields. Negative temperatures likely do not work: One concept that may seem closely related to the possible "thermal excitation of a laser" is that of "negative temperature". In a state of negative temperature higher energy levels have higher occupation probabilities than lower ...

1

Positive dispersion means that the lower frequencies are ahead of the higher frequencies in time, and this is caused by the fact that the crystal's group index (derivative of refractive index) is smaller for lower frequencies, giving them faster group velocity going through the crystal. To compensate, the pair of prisms gets the higher frequencies to catch ...

1

The simple answer is no, but that's because two separate laser beams cannot directly "com(ing) from same direction". Any two beams from separate sources which shine on a target with the centers aligned will have slightly different angles, and the distances from the emitter (and therefor the relative phase) will vary with location on the target. It's true ...

1

For practical purposes we can say that laser light only moves in one direction and that its intensity at any point that is in line with the laser light is independent of distance. That is not the case, depending on what exactly you mean by "for practical purposes". If you are using a laser beam to illuminate a target that is larger than the divergence ...

1

Each laser is made up of three main part: pump, amplifying medium and cavity. White laser is semiconductor laser; which means the amplifying medium is a semiconductor. In semiconductor lasers, pumping is electrical; which means the amplifying medium requires electrical power to be stimulated. The semiconductor of the white laser is an alloy made of zinc, ...

1

CO2 lasers tend to be very high power. Often they will have 100 W in the beam. They can be much higher. Some will burn through safety goggles about as fast as you can blink. Optical elements used with such lasers need to be designed for such power. When light strikes a coating, it is transmitted, reflected, or absorbed. Absorption must be kept down to a few ...

Only top voted, non community-wiki answers of a minimum length are eligible