You can use the same photo I use.
Start by duplicating the layer.
The desaturate it by going to Image>Adjustments>Desaturate or simply click Shift+Ctrl+U .
You should have this by now.
Now duplicate this layer and then go to Image>Adjustments>Invert or Ctrl+I .
You will obtain this.
Select for this layer Color dodge like in the picture.
Now go to Filter>Blur>Gaussian Blur.
There set these values.
And you should obtain something like this.
