On Easter Sunday the atmosphere of the Church switches gears, and instead of a focusing on death and sorrow, the Church is alive and resplendent with joy. Jesus is risen!
This is emphasized in a particular in many Eastern Churches. The week following Easter Sunday is called "Bright Week," and refers to the light that Jesus has brought into the world.
In biblical terms, Jesus rose on the "eighth day," which symbolically represents the new creation and the promise of Heaven. Eastern Christians reflect on this promise of future joy by referring to "Bright Week" as "one continuous day." Roman Catholics have a similar custom, treating each of the days in the Easter Octave as if it were Easter Sunday.
Fasting is strictly prohibited during this time, and it is in many ways a small foretaste of the glories of Heaven.
This week is also called by some "White Week," and refers to an ancient practice where the newly baptized would wear their baptismal gowns during the entire week. According to the Catholic Encyclopedia, the Second Sunday of Easter “was consequently known as dominica in albis (deponendis), the Sunday of the (laying aside of the) white garments.”
The whiteness of the robes and the wearing of white vestments also contributed to the name "Bright Week," radiating a bight white inside the church.
If there is a "theme" for Easter, it certainly is the "light of Christ," and everything in the Church highlights Jesus' bright light, scattering the darkness of sin and death.
Above all, the week after Easter is a time of intense rejoicing, reveling in the beauty and glory of Christ's resurrection.