# Light amplification

big prairie
-Light with higher frequencies has higher energy photons.

Can the energy in light be increased by increased amplitude without increasing frequency?

How can amplitude be increased without increasing frequency?

- By photons traveling in phasae creating a constructive interpherence?

Homework Helper
Light isn't really a wave in that sense - the wave picture is just an anology.

Think of a police car going past with a flashing light. If you drew a graph of brightness against position it would have a wavelength and a frequency but it it isn't a wave.

The energy of an individual photon is set only be the wavelength or freqeuncy. The brightness or intensity is set by the number of photons.

atom888
-Light with higher frequencies has higher energy photons.

Can the energy in light be increased by increased amplitude without increasing frequency?

How can amplitude be increased without increasing frequency?

- By photons traveling in phasae creating a constructive interpherence?

I'm trying to find out the answer myself. I don't think light can do constructive interferance like normal wave. It's like double intensity instead of double amplitude.

pallidin
As was said, amplitude is not a changeable aspect of an individual photon rather it is with respect to the amount of photons. Think of it this way... amplitude is only increased by increasing the actual amount of photons.

atom888
Yes, but in some perspective, we interest in high energy single photon and not many photons of lower energy. But like you say, it can't... or we just don't know how. However, if we keep bombarting a surface with same energy photon, we will get a higher and higher temperature (ignoring heat lost). Am I right? If that's the case, we can make higher energy photon using that tempeature?

Phrak
This is obviously a homework question of the type to "make students think for themselves", that fails miserably.

pallidin
This may be of some interest to you...

"One of the most commonly-used frequency-mixing processes is frequency doubling or second-harmonic generation. With this technique, the 1064-nm output from Nd:YAG lasers or the 800-nm output from Ti:sapphire lasers can be converted to visible light, with wavelengths of 532 nm (green) or 400 nm (violet), respectively.

Practically, frequency-doubling is carried out by placing a special crystal in a laser beam under a well-chosen angle. Commonly-used crystals are BBO (β-barium borate), KDP (potassium dihydrogen phosphate), KTP (potassium titanyl phosphate), and lithium niobate. These crystals have the necessary properties of being strongly birefringent (necessary to obtain phase matching, see below), having a specific crystal symmetry and of course being transparent for and resistant against the high-intensity laser light. However, organic polymeric materials are set to take over from crystals as they are cheaper to make, have lower drive voltages and superior performance."

From: http://en.wikipedia.org/wiki/Nonlinear_optics

big prairie
I believe that the attached immage is showing light refracting to cause constructive interference.

#### Attachments

• constructive interference.doc
45 KB · Views: 152
Staff Emeritus