Change your Background Color to #232323 then create a new document.

Create a New Layer and a New Path. Click the Brush Tool and have the brush on "Hard Round 1 Pixel" with opacity and flow at 100%.

Reset your colors and grab the pen tool and have the settings as shown on the hover.

Now you should already be on "Layer 1/Path 1". Have a look below for what we go to help you through this step. With the pen tool click on the upper left corner of the canvas go down to the middle a little bit and click and DRAG this time a little down and to the right and let go to get a nice curve. Go down a little more and to the right side and click again to get another curve going the other way. Play around till you get something like what we got below.

In the Paths Palette right click on "Path 1" and click "Stroke Path..." set the Tool to Brush and have the "Simulate Pressure" box unchecked then OK. Now deselect the path and go back to the Layers Palette. Change "Layer 1"(should be the layer with the white line) blending mode to Soft Light.

Duplicate this layer and Press CTRL + I to invert the color to black. Press CTRL + A then "V" to select all and take the Move Tool. Now press the UP arrow key on your keyboard TWICE.

Go back to the Paths Palette and duplicate "Path 1" by right clicking and clicking "Duplicate Path". Now grab your Pen Tool again with the same settings. Then click on the left side of the path on the canvas and click and continue clicking around until you get to the other side of the path on the right ensuring you create a fairly big enclosure.

Make the path a selection. Go back to the Layers Palette and grab the Gradient Tool and reset your colors again by pressing D and create a new layer.

Make sure your gradient tool is set to "Foreground to Transparent" and on the new layer click and drag from the top-right to the bottom-left.

Set the layer's blending mode to Soft Light and basically repeat steps 6 to 8.

But this time DON'T make a duplicate path, just use the other path you haven't used yet. Also now instead make the pen selection for the top of the curve and drag up with the gradient tool.

Merge Visible the layers and then grab the Eraser Tool. Then change your Background Color to #232323.

Now with the eraser tool just gently brush off the left side and the right side of the image that have hard sides.