You need to use two ar-coated (specifically for 450nm) cylinder optics together with a G7 focussing optic to get the best possible hotspot, highest efficiency and least amount of stray light. The cylinder lenses correct for the differently expanding axes of the rectangular laser beam. This can easily cost 100$, but itâs worth it.
The optical assembly and the cooling will probably give you the most grief.
Did you get a suitable, adjustable laser driver? I know a very compact one if you need it.
The engraving lasers they sell are doing .1mm^2 without any cylindrical optics, so Iâm going to try that first.
Thereâs no point in spending $450 on an acylindrical lens if Iâm already burning through the crystals without it.
The driver I bought can be regulated by 5v in addition to a current trim pot to adjust the maximum.
Also comes with a temp sensor for protection of the laser diode
Just tested the laser tonight, incredibly powerful, was at minimum power and it started burning a hole in some cardboard.
Unfortunately I seem to have some issue with my laser driver, so just using my DPS5020 power supply to drive the laser at constant voltage and it works great.
Planning to machine a custom copper heatsink for testing purposes, as I need to hold both the collimation lens and crystal at fixed distances.
My idea is to make a simple rectangle block that I can screw onto a CPU heatsink like the NH-D15 for some extreme cooling:
Then I can also make a second attachment for LED MCPCBs and I can easily switch my heatsink to whatever needs to be tested.
I also just purchased a special M9x0.5 thread tap (for the lens) to make the copper laser block.
Yup, closed room, goggles, fire extinguisher at the ready.
M9x0.5 is odd but found on almost all security camera/fpv camera lenses and laser lenses, it seems to be the standard for those things that need fine adjustability of optics.
I want a good cooler that would be standard for all my testing, for better repeatability
The NH D15 is basically the best cooler that wonât be a liquid cooler.