According to the current understanding of physics based on Einstein's theory of relativity, it is not possible for any object or information to travel faster than the speed of light in a vacuum. The speed of light in a vacuum, denoted as "c," is considered to be the fundamental speed limit of the universe.
If we imagine a scenario where an electromagnetic wave could somehow travel faster than the speed of light in a vacuum, it would violate the principles of special relativity. According to special relativity, as an object with mass approaches the speed of light, its relativistic mass increases, and the energy required to accelerate it further also increases. As a result, it would take an infinite amount of energy to accelerate an object with mass to the speed of light, making it impossible to surpass this speed.
In the case of an electromagnetic wave, its speed is always equal to the speed of light in a vacuum. This speed is determined by the electric and magnetic properties of free space, known as the permittivity and permeability of vacuum, respectively. Any change in the speed of light would imply a change in these fundamental properties, which is not observed in nature.
Therefore, if we consider the hypothetical situation where an electromagnetic wave travels faster than the speed of light in a vacuum, it would imply a violation of the laws of physics as currently understood. Consequently, discussing the behavior of such a wave in terms of wavelength or other properties becomes speculative and outside the realm of established scientific principles.