Yes, a strong gravitational wave can indeed affect light. According to Einstein's theory of general relativity, gravity is not only a force but also the curvature of spacetime caused by massive objects. When a gravitational wave passes through space, it causes ripples in the fabric of spacetime itself.
The effect of a gravitational wave on light can be understood in terms of the phenomenon known as gravitational redshift and blueshift. As the gravitational wave passes through an area of space, it can stretch or compress the spacetime along its path. This stretching or compression affects the wavelength of light passing through that region.
If the spacetime is stretched, the wavelength of light traveling through it will increase, resulting in a redshift. Conversely, if the spacetime is compressed, the wavelength of light will decrease, causing a blueshift. These changes in wavelength can be observed as a shift in the frequency of the light.
However, it's important to note that the effect of a gravitational wave on light is very small unless the gravitational wave is extremely strong. Gravitational waves generated by most astrophysical events, such as merging black holes or neutron stars, have minimal impact on light over astronomical distances. To detect and study the effects of gravitational waves on light, highly sensitive instruments such as interferometers are required.