Alaskan
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I've shared photo's of this build here before, now a video. Hope you like the show and tell of my dual wavelength combined 450 + 520 nm blue and green laser diode laser pointer made by CDROM777.
Chris
Introducing the LaserPointerForums followed by a video of the workings of a dual wavelength combined 450 + 520 nm blue and green laser diode laser pointer producing faux cyan approximating the look of 470 nm at several watts of output power (corrections below, read).
I may decide to remake this video soon without all of the Ah and um's and a semi-correction to a statement I made that there are no 4.5 watt 470 nm laser diodes. Although, technically, I was correct in that statement, because at the time of this recording there are no diodes available to us which are specified to operate at 470 nm producing 4.5 watts of output. However, you can purchase a NUBM07E 465 nm laser diode and over-drive it hard to get to about 5 watts or more at 470 nm because the wavelength shifts a few nanometers longer when driven hard beyond its specified upper current rating, but doing so the diode is exceedingly over-driven and has a substantially reduced life due to that. Also, these diodes come with an incorporated gball lens crimped into the cap which when removed (due to being too far from a perfect infinity focus too much of the time) often die an early life when the cap is removed exposing the diode substrait to the air.
The advantages of this build over a single uncorrected laser diode are:
1. First, because I like power and when you think that way, two diodes are better than one.
2. I like the result of adding corrective optics which change the shape of the beam closer to a square instead of the long rectangle you would have without them.
3. An added benefit of using the cylinder pairs for beam shaping is through their use to expand the faster diverging slow axis (which has a very thin profile on the output) results in reducing the divergence of that axis for a better match to the divergence of the fast axis, which contrary to what you might naturally assume, the fast axis actually has comparatively lower divergence with these diodes, so the thin side is the one you would want to expand anyway, and due to this characteristic a plus-plus benefit.
4. After shape correction and divergence reduction of the slow axis, the beam is further expanded (both the fast and slow axis equally) with the 3X beam expander on the output which further reduces the total divergence.
5. Another advantage is the laser diodes are being driven close to the manufacture ratings of the devices and should last for several thousand hours of use with much slower degradation without failure.
6. The input clear aperture of the 3X beam expander just happened to be barely large enough for the diameter of the beam coming from the cylinder pair optics and with the expansion within the expander caused a small amount of truncating, or clipping of the beam which fortuitously performs the function of a mask, removing the square shape and through this giving the final beam shape of a rounded spot, not planned, but worked out that way without loosing much power.
Other than shape, why correct the beam?
Chris
Introducing the LaserPointerForums followed by a video of the workings of a dual wavelength combined 450 + 520 nm blue and green laser diode laser pointer producing faux cyan approximating the look of 470 nm at several watts of output power (corrections below, read).
I may decide to remake this video soon without all of the Ah and um's and a semi-correction to a statement I made that there are no 4.5 watt 470 nm laser diodes. Although, technically, I was correct in that statement, because at the time of this recording there are no diodes available to us which are specified to operate at 470 nm producing 4.5 watts of output. However, you can purchase a NUBM07E 465 nm laser diode and over-drive it hard to get to about 5 watts or more at 470 nm because the wavelength shifts a few nanometers longer when driven hard beyond its specified upper current rating, but doing so the diode is exceedingly over-driven and has a substantially reduced life due to that. Also, these diodes come with an incorporated gball lens crimped into the cap which when removed (due to being too far from a perfect infinity focus too much of the time) often die an early life when the cap is removed exposing the diode substrait to the air.
The advantages of this build over a single uncorrected laser diode are:
1. First, because I like power and when you think that way, two diodes are better than one.
2. I like the result of adding corrective optics which change the shape of the beam closer to a square instead of the long rectangle you would have without them.
3. An added benefit of using the cylinder pairs for beam shaping is through their use to expand the faster diverging slow axis (which has a very thin profile on the output) results in reducing the divergence of that axis for a better match to the divergence of the fast axis, which contrary to what you might naturally assume, the fast axis actually has comparatively lower divergence with these diodes, so the thin side is the one you would want to expand anyway, and due to this characteristic a plus-plus benefit.
4. After shape correction and divergence reduction of the slow axis, the beam is further expanded (both the fast and slow axis equally) with the 3X beam expander on the output which further reduces the total divergence.
5. Another advantage is the laser diodes are being driven close to the manufacture ratings of the devices and should last for several thousand hours of use with much slower degradation without failure.
6. The input clear aperture of the 3X beam expander just happened to be barely large enough for the diameter of the beam coming from the cylinder pair optics and with the expansion within the expander caused a small amount of truncating, or clipping of the beam which fortuitously performs the function of a mask, removing the square shape and through this giving the final beam shape of a rounded spot, not planned, but worked out that way without loosing much power.
Other than shape, why correct the beam?
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