So far, the speed of light was measured using photons primarily.

However, there are distinct advantages in using lower-energy photons for the excitation.

The great advantage of using lower-energy photons rather than X-rays is the greater resolution attainable.

When using photons, it is placed after the beam has passed through the X-ray target.

They were conducted instead using photons.

Optical computing is to use photons rather than conventional electrons for computing.

To date there have been eight experiments, all but one of which used photons rather than protons.

Traditional lithography processes use photons which cannot be scanned and therefore masks are needed to selectively expose your sample to radiation.

Of course, the eavesdropper could generate and send a copy of the message, using new photons.

The exception to the rule, the Rowe et al. (2001) experiment was performed using two ions rather than photons, and had 100% efficiency.