Power output peaks at
68mW.
Post-long term stability analysis power output test.
Power output peaks at
70mW.
Long-term laser stability cum battery discharge analysis (
possibly in violation of an unpublished duty cycle recommendation) of this unit. As you can see, it ran for 2:50 before it started to peter out.
This is actually a retest; approx. 1.5 hours into the first one, I accidentally bumped something that I shouldn't have and subsequently queered the test; so I recharged the cell and started a second test. :-/
Test was conducted using a generic (
unlabelled) 2000mAh 18650 Li:ION cell.
Laser's case temperature over the lasing portion measured 82°F (27.8°C) at 2:20 into the test. Ambient temperature was 71°F (21.6°C) as measured using a
CEM DT-8810 Noncontact IR Thermometer.
I measured the laser temperature a number of times, and it never exceeded 82°F (27.8°C). This tells me that (
with the amount of electrical current being sunk) the heatsinking of the laser diode is either quite excellent or very lousy; though considering that the output power remains relatively stable, I'd go for "quite excellent".
The power generation curve of this lithium ion cell (well, all lithium cells & batteries actually) is known to be fairly uniform; only dropping off sharply near the end like somebody slammed the toliet seat onto its head. So it was no big surprise to me that this laser remained relatively stable (
varying in output power by less than 4mW -- maybe 5mW) for as long as it did.
I judge overall stability to be excellent considering that this a very low priced (for this unusual wavelength) consumer-grade laser!
The stability analysis (tab-delimited that can be loaded into Excel) is at
488nm.txt.
Repeat long-term laser stability cum battery discharge analysis of this unit. As you can see, it ran for 2:34 before it started to very rapidly go down the tube.
Retest was conducted using the same cell (a generic {
unlabelled} 2000mAh 18650 Li:ION cell).
Laser's case temperature over the lasing portion measured 87°F (30.6°C) at 1:43 into the test. Ambient temperature was 77°F (25°C).
I measured the laser temperature a number of times, and it never exceeded 88°F (31.2°C).
The stability analysis (tab-delimited that can be loaded into Excel) is at
488nm2.txt.
These tests were conducted on a
LaserBee 2.5W USB Laser Power Meter w/Thermopile.
Beam terminus photograph on a framed picture (laser was discharged onto the white portion) at ~12".
Beam image bloomed quite a bit; it also shows a lot of white that doen't exist in the actual beam.
Beam terminus photograph on a door at ~15 feet.
As with the above photo, the beam image bloomed quite a bit; it also shows a lot of white that doen't exist in the actual beam.
You should also be able to see the beam itself; this is in large part due to
Rayleigh scattering.
Photograph of the laser's actual beam outdoors; photo was taken at 8:57pm PDT on 08-21-18 in Shelton WA. USA.
Photograph showing the beam from this laser and the
Directly-Injected 5mW 505nm Bluish-Green Laser Pen outdoors at night. Photograph was taken at 9:42pm PDT on 08-22-17.
Photograph showing the beam from this laser and the
Directly-Injected 5mW 505nm Bluish-Green Laser Pen directed toward an interior door.<BR>
Photograph showing the beam from this laser and the
Directly-Injected 5mW 505nm Bluish-Green Laser Pen with the lasers positioned a distance away from the camera.
Photograph showing this laser's radiation reflecting off an interior window.
Photograph showing this laser's beam crossing a room.
Taken with photoflash.
Photograph of the square artifact just outside (
but very closely intersecting) the laser's beam. This pic was taken by irradiating a plastic bag hanging on the doorknob in such a manner that the artifact continued unabated so that it struck a white surface behind the bag; the bag itself absorbed the vast majority of the laser's energy.
A look "under the hood" as it were; this allows you to see the laser diode itself.
It's that small silvery-colored can-shaped structure near the center of this pic.
Here's proof that I really performed, "The Toliet Test" on it.
Needless to say, it passed this test with flying colors (colours)!
Considering that this laser is advertised to have a 5 meter submersibility rating, it had better pass!!!
PLEASE NOTE that this test was conducted in the cistern (
toliet tank); the water in this part of the WC is actually potable (
drinkable) so I did not have to sterilise the laser after this test; I only needed dry it with a bit of
bungwipe and I was good to go.
Spectrographic analysis of this laser.
Spectrographic analysis of this laser; spectrometer's response narrowed to a band between 475nm and 495nm to pinpoint wavelength, which is 488.7nm.
Spectrographic analysis of this laser; spectrometer's response narrowed to a band between 800nm and 874nm to check for the presence of a pump laser (
why bother when I know that a longer wavelength pump laser does not exist?) -- as you can plainly see, it really, truly doesn't exist!!! (
I irradiated the spectrometer's sensor quite well in effort to capture this!)
The raw spectrometer data (tab-delimited that can be loaded into Excel) is at
488point.txt
Spectrographic analysis of this laser taken after ~five (5) hours of continuous operation to check for spectral drift; spectrometer's response narrowed to a band between 475nm and 495nm to pinpoint wavelength, which is 488.370nm.
The raw spectrometer data (tab-delimited that can be loaded into Excel) is at
488poin2.txt
Spectrographic analysis of this laser after 25 minutes of continuous operation (
laser was not neutralised before taking this spectrum)
My
CEM DT-8810 Noncontact IR Thermometer is not capable of measuring the temperature of something as small as this laser diode.
Spectrometer's response narrowed to a band between 486nm and 491nm to pinpoint wavelength, which is 488.7nm..
Spectrographic data file (tab-delimited that can be loaded into Excel) is at
488nm9.txt
Spectrographic analysis of this laser taken after one (1) hour exposed to a relatively cold temperature; measuring 15°F (-9.4°C) -- this was the temperature of our household freezer.
Spectrometer's response narrowed to a band between 483nm and 490nm to pinpoint wavelength, which is 487nm.
Given that the laser junction (
the area that produces laser radiation) is exceptionally small -- approximately the size of a bacterium -- I honestly didn't expect to see any significant spectral shift.
The raw spectrometer data (tab-delimited that can be loaded into Excel) is at
488cold.txt
USB2000 Spectrometer graciously donated by P.L.
Spectral line halfwidth (FWHM) of this laser was measured at 2.1nm.
A beam cross-sectional analysis would normally appear here, but my
ProMetric 8 Beam Cross-Sectional Analyser that I use for that test was destroyed by an almost-direct lightning strike in mid-July 2013.
In leiu of a beam cross-sectional analysis, I present to you this photograph that shows the ovoid beam profile, which is characteristic of a diode laser -- this clearly shows that it has fast and slow axes.
The collimating lens (
*NOT*, "lense" 
) was removed from the laser for this photograph.
Brief video showing how this laser behaves when the battery is just about pooped out. Notice that it blinks rapidly instead of staying in CW (Continuous Wave) mode.
The music that you hear is zax from the coin-op arcade video game, "Afterburner ][" by Sega from 1987.
This product is not audio (sound)-sensitive in any manner; the music may safely be ignored or even muted if it piddles you off.
This video is 8,713,315 bytes in size; dial-up users please be aware.
Another brief video showing how this laser behaves when the battery is just about petered out. Notice that it blinks rapidly instead of staying in CW (Continuous Wave) mode.
The music that you hear is zax called, "Narrow+" from the Commodore 64 computer demo, "Pyromania" by the C=64 demo group Arson.
This product is not audio (sound)-sensitive in any manner; the music may safely be ignored or even muted if it piddles you off.
This video is 38,816,017 bytes in size; dial-up users please be aware.
Review of the Directly-Injected 5mW 488nm Greenish-Blue ("cyan") Laser Pen
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