Start by creating a rectangle using rectangular shape tool.
Double click the layer to open layer style window. Apply layer style with the settings shown.
From layer menu select layer style>>create layers.
Select the layer just above the rectangular shape layer. Press Ctrl+Alt+G to remove clipping mask from the all the layers.
Select all the layers and merge.
From filter menu select artistic>>neon glow.
Press Ctrl+U to open hue/saturation window. Apply settings as shown.
Duplicate the layer. Press Ctrl+T. Right click the layer and select flip horizontal. Change the layer mode to hard light.
Duplicate the layer again. Press Ctrl+T. Right click the layer and select rotate 90°. Change the layer mode to screen.
Duplicate the layer again. Press Ctrl+T. Right click the layer and select flip vertical. Change the layer mode to pin light.
Select and merge all the layers. Duplicate the layer. Press Ctrl+T and scale up the layer.
Change the layer mode to color burn.
Create a duplicate of original layer and scale down the layer. Change the layer mode to hard light.
Select and merge all the layers. Duplicate the layer. From filter menu select stylize>>glowing edges. Apply settings as shown.
Change the layer mode to overlay.
