Review of the Prome 301 Red Diode Laser

[The_LED_Museum]

301 PROME RED LASER PEN

Retail $9.90 (laserpointerstore.com...)

Manufactured by (Unknown)
Last updated 04-04-20

This is a red-emitting diode laser in a fat pen-style body.
It uses a single 18650 Li:ION rechargeable cell for its power source.

It's rated to produce 150mW of laser radiation at 650nm in the red part of the spectrum (these values were measured at 176mW with a wavelength of 664.9nm).

Because this is a laser, you should not shine it into your eyes, other people's eyes, pet's eyes, etc. Just use a little common sense here, k? (It's a bit over spec anyway -- you definitely DO NOT want to use this as a cat toy!

)

SIZE

To use your shiny new Prome Red Laser Pen, just press the button on the barrel and hold it down for as long as you need the laser beam; release it to neutralise the laser.

The laser's focus can be adjusted from infinity (extremely narrow spot even at some distance) to a medium, oblong spot by rotating the bezel (head).

To change the battery in this laser, unscrew & remove the tailcap, and set it aside. If for whatever reason you can't unscrew the tailcap, the laser can be unscrewed about 2/3 of the way down the body (when the "business-end" is aimed skyward

Tip the used 18650 cell out of the barrel and into your hand, and recharge it.

Insert a freshly-charged 18650 cell into the barrel, button-end (+) positive first. This is the opposite of how batteries are installed in most other laser pointers & pen-style portable lasers, so please pay attention to polarity here.

Screw the tailcap (or the bottom 1/3 of the laser) back on, and be done with it.

Current consumption measures 250mA on my DMM.

The Prome Red Laser Pen is sprinkle-resistant at very minimum. So you need not worry about carrying and using the laser in LIGHT rain or snow -- but if you really do get mud or bird shit in the output aperture, you may indeed be SOL.

Below, you'll find my power output and spectrographic findings.

Beam terminus photograph on a wall at ~12".
Beam image bloomed CONSIDERABLY here; the beam is quite compact & clean in reality.

Beam terminus photograph on a wall at ~10 feet.

The power output measured 176mW on a LaserBee AX 3.0 Watt Laser Power Meter w/Thermopile with known-good metrics.

Spectrographic analysis of this laser.

Spectrographic analysis of this laser; spectrometer's response narrowed to a band between 660nm and 670nm to pinpoint wavelength, which is 664.9nm.

The raw spectrometer data (tab-delimited that can be loaded into Excel) is at prome.txt.

USB 2000 Spectrometer graciously donated by P.L.

A beam cross-sectional analysis would normally appear here, but my poor defenseless helpless innocent ProMetric Beam Cross-Sectional Analyser that I use for that test was destroyed by an almost-direct lightning strike in mid-July 2013.

​

TEST NOTES:
Test unit was purchased on Ebay on 01-09-19, and was received on 01-24-19.


UPDATE: 00-00-00


PROS:
Decent beam quality
Properly labelled for wavelength & power output
Battery it uses is rechargeable -- no disposables to worry about
Keyed interlock switch -- a feature not often seen with portable lasers



NEUTRAL:
Collimating lens assembly has a slight "loose" feel to it


CONS:
Unit as a whole has a very slightly "chintzy" or cheap feel to it

MANUFACTURER: Unknown
PRODUCT TYPE: Fat "pen"-style portable laser
LAMP TYPE: Directly-injected red-emitting laser diode
No. OF LAMPS: 1
BEAM TYPE: Adjustable from very narrow spot to medium oblong spot
REFLECTOR TYPE: N/A
SWITCH TYPE: Momentary pushbutton on/off on barrel
CASE MATERIAL: Metal
BEZEL: Metal; laser diode, collimating lens recessed into deep hosel for them
BATTERY: 1x 18650 Li:ION rechargeable cell
CURRENT CONSUMPTION: 250mA
WATER-RESISTANT: Sprinkle-resistant at maximum
SUBMERSIBLE: No
ACCESSORIES: 2x tailcap interlock keys
SIZE: 222mm L x 11.20mm Dia.
WEIGHT: 83g (2.93 oz.) empty -- 128g (4.55 oz.) incl. battery
COUNTRY OF MANUFACTURE: Unknown; but presumably China
WARRANTY: Unknown/not stated


PRODUCT RATING: