Power output peaks at
47mW (power output peaked at 58mW when I was performing the stability analysis).
Post-long term stability analysis power output test.
Power output peaks at
50mW.
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possibly in violation of an unpublished duty cycle recommendation) of this unit.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 3:04 before it started to peter out.
Test was conducted using a generic (
unlabelled) 2000mAh 18650 Li:ION cell.
Laser's case temperature over the lasing portion measured 83°F (28.4°C) at 3:00 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 83°F (28.4°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 6mW or less) 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!
VERY IMPORTANT!!! That "spike" at 1:15 was generated by me closing and then opening the display on my laptop computer; this caused the flimsy little table that I have everything set up on to jiggle; I quickly repositioned the laser and the LPM's sensor and allowed the test to continue.
The stability analysis (tab-delimited that can be loaded into Excel) is at
505nm.txt
Repeat long-term laser stability cum battery discharge analysis of this unit. As you can see, it ran for 2:21 before it started to very rapidly peter out.
Retest was conducted using the same cell (a generic (<i>unlabelled</i>) 2000mAh 18650 Li:ION cell).
Laser's case temperature over the lasing portion measured 81°F (26.7°C) at 2:14 into the test. Ambient temperature was 73°F (22.8°C).<BR>
I measured the laser temperature a number of times, and it never exceeded 82°F (27.8°C).
The stability analysis (tab-delimited that can be loaded into Excel) is at
505nm2.txt.
Third long-term laser stability cum battery discharge analysis of this unit. As you can see, it ran for 2:47 before the power output started to very rapidly go down the toliet.
Retest of the retest was conducted using the same cell (a generic (
unlabelled) 2000mAh 18650 Li:ION cell).
Laser's case temperature over the lasing portion measured 83°F (28.4°C) at 2:33 into the test. Ambient temperature was 72°F (22.2°C).<BR>
I measured the laser temperature a number of times, and it never exceeded 83°F (28.4°C).
The stability analysis (tab-delimited that can be loaded into Excel) is at
505nm3.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 doesn't exist in the actual beam.
I DO NOT HAVE A 532nm GREEN DPSS LASER TO COMPARE THIS ONE WITH, SORRY!!! 
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 doesn'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 ootdoors; photo was taken at 11:09pm PDT on 08-18-18 in Shelton WA. USA.
Photograph showing the beam from this laser and the
Directly-Injected 5mW 488nm Greenish-Blue ("cyan") 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 488nm Greenish-Blue ("cyan") Laser Pen directed toward an interior door.<BR>
Photograph showing the beam from this laser and the
Directly-Injected 5mW 488nm Greenish-Blue ("cyan") Laser Pen with the lasers positioned a distance away from the camera.
A look "under the hood" as it were; this allows you to see the laser diode itself.
It's that small brass-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 loo 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 500nm and 520nm to pinpoint wavelength, which is 507.2nm.
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
505point.txt
Spectrographic analysis of this laser taken after ~three (3) hours of continuous operation to check for spectral drift; spectrometer's response narrowed to a band between 500nm and 520nm to pinpoint wavelength, which is 505.4nm.
The raw spectrometer data (tab-delimited that can be loaded into Excel) is at
505poin2.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 504nm and 509nm to pinpoint wavelength, which is 506.1nm.
Spectrographic data file (tab-delimited that can be loaded into Excel) is at
505nm9.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 500nm and 510nm to pinpoint wavelength, which is 504.4nm.
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
505cold.txt
USB2000 Spectrometer graciously donated by P.L.
Spectral line halfwidth (FWHM) of this laser was measured at 2.8nm.
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 petered out. Notice that it blinks rapidly instead of staying in CW (Continuous Wave) mode. I looped it two times to accomodate the length of the music.
The music that you hear is zax from the Commodore 64 computer game, "Master of the Lamps" by Activision from 1984.
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 60,996,775 bytes in size; dial-up users please be aware.
Review of the Directly-Injected 5mW 505nm Bluish-Green ("mint green") Laser Pen
)
Reply With Quote
Originally Posted by barthchris
