The optics will work for bridgelux or epistar. Just search 3w led
optics, or just led
optics and arrange results by price lowest first and scroll through reading the descriptions until you find what you want.
I've bought a lot of LEDs off eBay.
Here's a pic of either bridglux or epistar 3w LEDs that are not yet mounted on a star with their optics next to them.
Any optics for 3w LEDs will fit your bridgelux 3w LEDs .