The vaulting pole is a very advanced piece of equipment. It is constructed from carbon fiber and fiberglass composite materials in several layers. The pole must be able to absorb all of the vaulter's energy while bending, and then return all of that energy as it straightens out. These advanced composite materials waste very little energy when they bend, and have a good strength-to-weight ratio.
A 200-lb (90.72 kg) pole vaulter needs to put about twice as much energy into the vaulting pole as a 100-lb (45.35 kg) vaulter. But the vaulting pole has to bend about the same amount, this means that the heavier vaulter needs a stiffer vaulting pole than the lighter vaulter. So, the stiffness of the vaulting pole must be carefully tuned to match the weight of the vaulter.
Anything that helps the vaulter run faster on his approach will help him go higher. Reducing the weight of the vaulting pole is an obvious way to help the runner go faster. The carbon fiber poles used today are much lighter than the wood, bamboo or metal vaulting poles sometimes used in the past.