Hey jake. ok thats better but the best we can hope for is +-5% but more like +-10% with an LPM that has not been rigourously calibrated on a regular basis with a known source. so those measurements are still well within the accuracy tolerance of the sensor/meter and cant be attributed to the lens. I dont think we can get much better than a good quality AR coated lens like the G1 or G2. i think the only thing that might be better is a lens that has coatings that are specific to a narrow band of wavelength.
but thats cool. good to have options!
Thanks Plexus. I said this time and time again, especially after the G-1 was said to be better than the G-2. Sorry for the late response, but I can't hang out here too often. NOt an attack, just laying out of facts...
I have an Ophir Vega with 3A head and yes, a few mW's at these ranges is measurable, but not within the accuracy of the meters. Look back at the original tests of Jay's: It's 4mW I think at either 250 mW of 405nm, if I recall. I never saw Dave's numbers. The results are less than the meter's accuracy, thusa below experimental error.
I think a statistical graph is needed to compare the two lenses- just like the A130 and A140 diodes were compared. It was 10 to 12 diodes of each type put into one graph. Statistically, and graphically, one could see a trend of the 140 powers all above the 130 line. And I think this was done with data from various members. Best if one graph is used from one test.
Again it really might not matter since the difference may be very small. It's hard, as just screwing in one lens and putting another in can mess up the experimental measurement. I was thinking of a slide mount or turret that could hold each lens type- thus switching between lenses is quick.
I also wanted to comment on the variations between G1 and G2. Designs are basically the same. 1) they are from two different manufacturers. Manufacturer A has original molds and equipment from the original maker/ designer of the lens. Company B copied the design, as did Company C (Oh yes, there is a 405-G-3, and actually a 4 too but we won't get into that.) So the designs themselves could have slight variations 2) two coatings. G-1 is a single layer Magnesium Fluoride, about a 1% reflection per lens surface. G-2 is a multilayer "A" coating taking the reflection per surface down to about 1/2% per surface. Normal glass is about 4% reflection, per surface , Uncoated. On paper, the G-2 should have a lower loss, but that difference is still small, and beyond accurate measurements.
I went to the G-2 due to quality issues seen with early lenses from Company A. That was a business decision I made on behalf of my other customers- laser manufactures who demand ISO quality standard, etc.