I use a T5 fixture fitted with full spectrum plus UV bulbs. Hortiluxe makes a whole line of these with different spectrums but I find Agromax bulbs hold their brightness longer than the hortiluxe. Has both UV A & B plus full spectrum. I put four of these alongside a 600w hps which really puts the frost on them.
Even a short fixture will make a difference. I'm impressed with how adding UV expands the footprint of your light without adding much heat or using much power.
It's UV-B NOT UV-A that does that..... 280 to 315 nm band range....
Keep in mind that not all UVb bulbs work well, as they have a very limited penetration depth.
Example: Reptile bulbs and fixtures - Only have about 18 inch's of actual effective distance from the bulb...