Hello There, you seem to need the formula on how to create a "Light-saber" like effect like the ones from star wars. Well, today's your day, for we are going to learn how to do just that. :)

• The Base

    At first, create an image with a black background, think of it as your layer to see the effect of the light saber and such.

• The Laser Beam

    Secondly, paint an oval-like shape using the circle selection (or a similar kind of..)  tool and paint it with white. However you can also use created shapes from paint brushes and sort.

• The Lightsaber Color and the Final Touches
  

    Next, create another layer above the layer with the white oval beam, for  we would paint the lightsaber color,  now create a larger oval for the beam color, it should cover more than the white beam's reach.   Afterwards, apply  the "Gaussian Blur" Effect and set the layer mode to "Screen".

• Last words

    I hope you learned something from this tutorial, now you can make "Lightsaber"-like Glows. And you can even use it in your photomanipulations and sort.

Have a great day.