This is a Spotlight that uses the Spectron procedural lighting system. Spectron is exposed as a Procedural light node type, which you can use for quick volumetric effects and spotlight generation (figure 1).
Figure 1: Volume Spotlight
Target Mode - Creates a target to orient the spotlight.
Target dist. - Set the target a specific distance from the light source.
Throw Distance - Max distance the spotlight will affect.
Cone Width - Controls the spread of the light.
Light Medium - Lets you use a specific medium.
Emitter MaterialThe representation of the surface or volume properties of an object. - Define a material with emission properties to control the light source.
Barn Doors Material - Define a material for the barn doors.
Enable Barn Doors - Toggle the barns doors on or off.
Barn Doors Size - Scales the barn doors.
Barn Door Angle - Controls the barn door angle to control light occlusion.