First Sanwu Order: Best visible night laser?

[tokiwartooth]

I am considering ordering a Challenger II in either 520nm at 150mw, 525nm at 200mw, or 445nm at 3W. These are all around the same price point. The more powerful green lasers cost $200-250 more.

Which of these options would be the brightest and most visible at night? We want to be able to point to stars, but also want to produce the thickets/most visible beam. Also, will a beam expander really help with these tasks?

Also, I'm not sure if I should get multimode vs single mode. I've read single mode lasers perform a bit better than multimode lasers. However, I could see being able to reduce the power to low/medium/high/strobe could be useful.

Thank you for the advice.

 

[Cressa]

The blue should have the most visible beam of those options, and it's just a beautiful color. All 3 of those lasers are good, but that said, for that purpose, I recommend going with the 1W red. Red is far less disruptive to human vision in the dark, and the 635nm wavelength is still *very* visible at that power level.

A beam expander isn't needed for this purpose at all, and mode is really personal preference. I'd go for it if you think you'll be using it.

 

[kecked]

Green mw for mw is the brightest.

 

[steve001]

Peak visual sensitivity is 555.5 nm.

Relative Laser Brightness Calculator

Multimode refers to the operation of the switch. Actual multimode refers to a laser beams profile. TEM00 is a Gaussian profile. Other profiles are TEM01, TEM02...

 

[julianthedragon]

I am considering ordering a Challenger II in either 520nm at 150mw, 525nm at 200mw, or 445nm at 3W. These are all around the same price point. The more powerful green lasers cost $200-250 more.

Of these, personally I think the 525nm 200mw is the best option. Don't be fooled, you don't need a 3W laser for it to be bright, 200mw of green is brighter than anything I had for the first 10 years I was in this hobby and it should be about the same brightness as the 3W blue.

We want to be able to point to stars, but also want to produce the thickets/most visible beam. Also, will a beam expander really help with these tasks?

I think there is a misconception that "thickest"="most visible". A thicker beam means the light is being spread out more, which lowers the intensity. Imagine packing a ton of light into a small place (kind of what a laser is in the first place)--that is going to be brightest. Also, multiwatt blues have high divergence (spreading of the beam) which make the greens better contenders for star pointing.

Beam expanders help make the beam thicker and lower divergence significantly when focused right, so if that's the effect you want you could probably choose either blue or green.

Also, I'm not sure if I should get multimode vs single mode

I think you are talking about the button modes sanwu offers which I can't really speak to, I've always gotten the single operation mode. However, see steve001's reply. When you see people here talking about singlemode/multimode it's usually about the beam profile which might be confusing. It's likely that neither the blue or green direct diode lasers from sanwu will be singlemode, which is fine.