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Re: New Nichia 9mm 1W 520nm diode
Thanks for the info. I didn't know the stuff about the 3 element lens.
Lenses only bring the angles into focus. The line is a focus of the emitter shape, corrective optics make that line more into a circle by compressing it.
Divergence grows with emitter widths.
Turning a raw diode beam into a spot is collimation of the angles, when doing this the source beam expands in the near field and decreases in the far field. All diodes can be colimated but the beam will be huge if the initial divergence is also quite large.
So when making a laser for shows the source need to have low initial divergence in order to colimate it and still have a beam that fits on Laser scanner mirrors which ideally means < 3mm
For Laser pointers this does not matter because it is not required to have a <3mm beam.
All diodes can be used / colimated but the trade of is beam diameter.
RA_Pierce: you don't need to have a special lens produced; you can buy larger lenses already and make a broader 3 element colimator but that is a trade off when you can do it with prisms.
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I don't know the specs of the 3-element lenses but they don't get as close to the diode as the G lenses so some of the beam gets cut off and that is where most of the power loss comes from. This "cropping" effect and the longer focal length is what makes the divergence a little better."
The reason for the cut off is not due to distance from the diode, it is that the divergence has been lowered which results in a larger beam inside the 3 eliment lens, you are actually cutting off the real size of the beam.
I did a lot of research into diode colimation and have a huge test stck of lenses numbering around 3,000: so when I start to try a diode I can find pretty quick the right lens combination for a desired target beam.
Thanks for the info. I didn't know the stuff about the 3 element lens.