Space/Science — HabitableZone

Space/Science » in reply to far out of the box

reread my above post...
R.L. — (archived)

The conservation of energy issue I referred to is the idea of a molecule absorbing a long wavelength photon and emitting a shorter wavelength photon, this can only happen if the molecule is in an excited state to begin with.

Now, there are ways to convert long wavelengths to shorter ones... for instance, in the YAG lasers I work with the YAG rod lases at 1064 nm wavelength, we then pass the 1064 nm light through crystals of LBO or KTP (nonlinear crystals) and VOILA out comes photons with twice the energy and half the wavelength, 532 nm... to put it very simply, two 1064 nm photons are 'added' in the crystal to become a single 532 nm photon- energy is conserved.

Another example is harmonic generation, but that reqires intensities of stimulating laser light that are not possible on a large scale...

None of the above helps you in your idea...

What you need is a molecule that STRONGLY absorbs over a large range of long IR and will radiate a shorter wavelength photon after absorbing multiple longer wavelength photons, In the application you envision this is just not realistic... (There are so many reasons why, that I wont list them unless pressed). The term you are looking for is not lasing but fluorescence, lasing implies coherence. What you are describing is different.

When the laser guide star laser beam hits the sodium atoms in the mesosphere it puts them in an excited state, when they return to their ground state the radiate at the same enrgy they were excited by- but they are NOT lasing, they are fluorescing...

My understanding of the lasing effect is admittedly just the basics. But it seems to me that it's capable of--or perhaps inherently does--transform the frequency of energy. It'd have to in order to produce output of a single frequency. Right? Is the energy dumped into, say, an X-ray laser, of a lower frequency?

Lasers CAN change the frequency of light in some sense of the term... In the YAGs I use the YAG rods are excited by broad spectrum light from a flashlamp and lase at a narrow frequency of 1064 nm. In the dye laser part of my system we excite the dye molecules with 532 nm light and extract 589 nm light...

Man, I tend to ramble...

Log in or register to post.

The whole thread (71 posts)