Most high powered red diodes will have this line, it is nothing to do with the lens, it is simply an artifact on high powered diodes due to the shape of the emitter. It is not actually a singe point, although the bulk of the lasing (99.9%) comes from a single point , the emitter zone is actually a very thin line.
I actually proved this before with a series of pictures looking into the optic cavity of a LD right on the lasing threshold, they are somewhere on LC, I will try and retrieve them for you. I was using a simple 5mw diode connected to my precision Power supply and took a series of pictures right at the lasing threshold, increasing the Voltage by 1mv at a time. The camera is actually pointing INTO the diode window, so you can see what is happening at the emitter
Ok just found them. you will see the emitter is actually a line, with the main lasing point appearing as the voltage is increased.
Jase