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Review of the Directly-Injected 488nm Greenish-Blue Laser Pen

Benm

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Looks like a very nice laser to me!

With 70-ish mW power output i would not really expect any thermal problems or a required duty cycle as long as it is constructed decently, which it seems to be. It seems fit for continuous operation really, up to fully discharging a battery and then just popping in a fresh one.

The only thing that strikes me as odd is on how slowly the output power comes on, unless that's just an artefact of the power meter - which seems likely with a TEC based meter and time to reach real reading of 30 seconds or so.

Where did you get this laser from, and at what price? Or is it not available for purchase to the general public (you mention $66 resale but not from where)?
 
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The_LED_Museum

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Looks like a very nice laser to me!

The only thing that strikes me as odd is on how slowly the output power comes on, unless that's just an artefact of the power meter - which seems likely with a TEC based meter and time to reach real reading of 30 seconds or so.

Where did you get this laser from, and at what price? Or is it not available for purchase to the general public (you mention $66 resale but not from where)?
The LPM is thermal, not photoelectric; using my 1st generation Mark VII eyeballs, the laser appears to reach full output as soon as the switch is closed (well, within a few µS anyway) but with the type of LPM that I used, the measurement takes 30 to 40 seconds while the thermopile increases in temperature as it is irradiated.

I obtained the laser on Ebay. One such listing is at this link and another is right here.
 
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cistercian

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I just ordered one off ebay. I have wanted this wavelength for awhile. I do not like the lithium power but I have some protected panasonic cells I use in my jetlaser 1 watt direct diode green lasers.

I am glad I checked the board. I will LPM it when it gets here and post the results!

Great review as always!!!!
 

Benm

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The LPM is thermal, not photoelectric; using my 1st generation Mark VII eyeballs, the laser appears to reach full output as soon as the switch is closed (well, within a few µS anyway) but with the type of LPM that I used, the measurement takes 30 to 40 seconds while the thermopile increases in temperature as it is irradiated.

I obtained the laser on Ebay
Oh, the slow ramp up in power measurement is due to the LPM then, if you have lasers like dpss greens that need to warm up a bit before getting to full power you'll notice the changes in brightness upon powering it up by eye.

Getting these things of ebay always a bit tricky, you never know if and when vendors find a cheaper supplier for something that looks the same but has lower performance, and then just start sending those because of reputation gained previously.

The links you mention seem to be long term vendors with good track records though, temped to buy, despite not really liking the design that much.
 

Miya

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69mw.. What kind of lens? I think a 3element lens
 

The_LED_Museum

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69mw.. What kind of lens? I think a 3element lens
I can't tell for certain just by looking at the lens in the bezel; it could be a multi-element, or it could be just an acromat or even a simple DCX. :p
 
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paul1598419

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Do you not recall where/when you got this lens assembly? All the single short FL aspherics I've seen come in brass housings. The acrylics are in black housings like multi-element lenses, but are shorter and focus to infinity very close to the end of their housings. The two and three element lenses are in black metal housings, but are long enough to focus without bottoming out.
 

The_LED_Museum

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Do you not recall where/when you got this lens assembly? All the single short FL aspherics I've seen come in brass housings. The acrylics are in black housings like multi-element lenses, but are shorter and focus to infinity very close to the end of their housings. The two and three element lenses are in black metal housings, but are long enough to focus without bottoming out.
The lens assembly came OEM as part of the laser.

FYI the lens housing is black if that means anything; whether this is a stock lens assembly or a custom-made one just for this series of laser is simply not known.
 
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The_LED_Museum

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Bumpity bump bump: Ran a repeat long-term laser stability cum battery discharge analysis; also performed "hot" spectroscopy after ~25 mins. continuous operation to check for wavelength drift.
 

The_LED_Museum

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i ordered a second.I will post results.
I await your findings with baited breath!!! :D

In the meantime, I performed "cold" spectroscopy of this laser earlier today.

I exposed the laser for one (1) hour to a relatively cold temperature; measuring 15°F (-9.4°C) -- this was the temperature of our household freezer. I don't own or have access to any cryogenic equipment, so this is the best that I can do. :p

The wavelength measured 487nm.

I didn't expect to see a lot of shift, considering that the active (lasing) area is extremely small -- approx. the size of a bacterium, and would therefore heat up very soon after power was applied. The temperature of the diode housing itself would rise more slowly, keeping the laser junction a bit cooler than it might otherwise be -- hence there was *SOME* spectral downshifting. :)

The update (incl. spectrographic chart and data file) is scheduled to be installed in my O.P. tomorrow morning.
 
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