Sorry if this is considered necroposting, but I was looking for threads about C-mount housings and I found this one, which surprised me in a good way. Until now, I thought that a "weird" shape like a C-mount would need a strange and expensive housing... instead it uses the same kind of heat sinked housing that I've seen at O-Like for years! And the pictures in this thread even show how the diode itself is mounted! Much simpler than I thought.
Then I read a description that left me wondering...
If this is true, has anyone ever opened an IR labby from O-Like to check whether some of the light from the diode is dispersed too much and heats the heat sink instead of reaching the lens? Could it be that you just need to add a lens before the focussing lens in order to increase the power of those lasers and keep the heat sink cooler?
I'm sure there are some that will consider it necroposting, but when an old thread holds pearls of wisdom that are still relevant then it may be best to bring it back to the surface from time to time. This would be one of those, since C-mount solutions are few and far between.
I read through this thread, and the questions you have should have been addressed before. Had I been active in this forum when this thread was active, I would have offered some suggestions that could have helped. Unfortunately, hobby lasers tend to ignore one of the fundamental issues that plague multimode laser diode use. Unfocused emissions tend to look like a bar, instead of a dot or close to round oval. It's hard to get a good dot shape in the majority of these builds. The emissions that do not make it through the optics cause a loss in optical output power, and can contribute to heating up the host in the higher powered builds.
I work with bar mount, C-mount, and 9mm laser diodes more than I do with the smaller ones. This is because I use higher power lasers for research. I prefer to build my own labbies rather than buy because I can build them to exactly what I need, and save money in the process. Because of this, I have some familiarity working with these larger multimode laser diodes.
The answer you seek lies in the use of Fast Axis Correction (FAC) optics. The emissions from the laser diode diverge faster on one axis as compared to the other. Adding a FAC optic very close to the front facet of the laser diode can correct this to allow more of the laser emission to enter the collimation/focus optic(s). You can find FAC optics on eBay or other sources, but try to stay away from plastic optics for the higher power laser diodes.
Obviously, the pros use FAC optics that are coated for the wavelength in use, but even uncoated FAC optics are better than no FAC optic at all. Do a little study on the subject and you may just find that you can improve upon your results with very little effort. There's plenty of room in most C-mount hosts for adding a small FAC optic right to the front of your C-Mount laser diode. Another option might be to buy a C-mount laser diode that already has a FAC installed.
I hope this helps
Bob
