yeah we worked on "wavefront sensors"

what we would do it shoot a collimated beam (zero abberation) into the eye. as it would reflect from the spherial back of the eye backout again, any defects of the lens of the eye would be imparted to the beam

then the wavefront sensor, which consists of a microlens array over a CCD camera could breakdown the abberations and display it graphically for a LASIK surgeon to get real time feedback on his/her effect on the vision


something like this




with this result

and abberation of a collimated light can be broken down into mathmatica;l components called zernike coeficients so that any form of vision defect could be mathmatically described. the machine actually works better than the optometrists can do. But its not FDA approved in America so we only sold em in the EU and Asia



zernike coeficients

Quiet...all I can say is GOD BLESS YOU because LASIK changed my life! You ROCK!

As for the zernike coeficients - that must be how we get the lovely topo images of my eye! Very cool to learn something new!

(And that's why girls like science! )

the really cool job I had was being Lab Manager for a different outfit doing spectroscopic research on non invasive modeling of tissue analytes. basically in vivo real time spectroscopy

we were using michelson type interferomters to shoot modulated light into human tissue and then gathering the backscattered (anisotropic) photons and then decomposing the modulation to get blood glucose levels

saving diabetics from having to poke their fingers all the time

and the same system works for blood alcohol measurements, and we had a contract with a major firearms manufacturer (not allowed to say who) to develop biometric recognition sensors (so the gun would only fire for its owner). those systems are still in development

the machine worked really well, but we had problems getting it cheap enough for Medicare to pick it up. I still get emails from em all the time. They are still working on it

This is SO cool!



Genius!

I was just reading wiki

for Carlos, there is a really good page in wiki that explains characteristics of photons

http://en.wikipedia.org/wiki/Photon

I usually lose interest in discussions with people who favor adolescent trolling, attention seeking behaviors, insulting generalizations about women, and insults based on their own lack of reading comprehension - but the question you are asking is such a good question.

Light has no true mass, but I wouldn't say it consists of 'nothing'. Light has energy and, if I remember correctly, localized time-varying electromagnetic fields. It doesn't surprise me that a massless packet of energy would impart kinetic energy - and afaik imparting momentum and imparting kinetic energy always go hand in hand for objects with mass.

You suggest that momentum 'is' a force, which is wrong, but afai-remember you are correct to expect that a force must be applied to an object for it to gain momentum. I do not remember the exact mechanism by which light applies a force when it is absorbed or reflected, if I have time I will read the wiki QM mentioned. Or maybe QuietMan. has already explained...

As far as massless phenomena imparting forces, you have only to look at a charged particle tossed into either a magnetic or electric field. These fields apply forces, yet the field has no 'mass'.