An irradiation device capable of emitting electromagnetic radiation at variable beam angles, comprises a housing assembly including a longitudinal shell, the longitudinal shell having a first end and a second end, a first end cap assembly provided at the first end of the longitudinal shell, and a second end cap assembly provided at the second end of the longitudinal shell, a radiation source provided within the longitudinal shell, a movable lens having two ends, a first end of the movable lens provided within the first end cap assembly and a second end of the movable lens provided within the second end cap assembly, and one or more translational mechanisms provided within one or more of the first end cap assembly and the second end cap assembly, wherein the one or more translational mechanisms are adapted to cause linear motion of the movable lens with respect to the radiation source.