Laser pointer Power Reduction

[razerizlazer]

Hello everyone! I am new to the world of lasers and I am currently working on an academic project that involves the use of 808nm lasers. Since I have limited time and resources, I decided to purchase two 808nm 500mW lasers. The laser is similar to the Jetlaser PL-E 808nm Infrared Lasers. jetlasers.org/pl-e-pro/20-pl-e-pro-808nm-infrared-lasers.html

instead of building my own laser from scratch.

However, for some of my experiments, I need to use a lower power output. I am wondering if there's a way to reduce the power output without having to dismantle the laser equipment. According to the specs, the laser can be operated with a 5V AC adapter, but the amp is not mentioned. Is it possible to reduce the power output to 100mW, 200mW, or similar levels using an external voltage regulator or any other device?

Also, I am curious about the "Beam quality M²". Can anyone please explain what it means and how I can find out the beam quality of my laser?

I would appreciate any help and advice on these matters. Thank you.

 

[milantheone]

your laser will have driver board inside..

they used to have potentiometer, or shunt resistor..

measure voltage across shunt resistor divide it by resistor value and you get current going to the diode..

if you need to lover output of the diode replace the resistor with required value which is obviously higher ohm resistor..
with potentiometer it is obvious..

you need to be good at soldering obviously as those parts are small and modifiations need some skill..

 

[razerizlazer]

your laser will have driver board inside..

they used to have potentiometer, or shunt resistor..

measure voltage across shunt resistor divide it by resistor value and you get current going to the diode..

if you need to lover output of the diode replace the resistor with required value which is obviously higher ohm resistor..
with potentiometer it is obvious..

you need to be good at soldering obviously as those parts are small and modifiations need some skill..

Hello. Thank you for the reply. I did go through some posts. Is there any other way to reduce the power by using any external device? As my laser support AC adapter of 5V. I dont want to open my laser. Thank you

 

[Nuguns]

check my posts on my profile about my 488-492nm 60-70mw dimming using an ND filter

No guarantees if it will work with such high power. Key things to heed, safety glasses which u should already have, keeping the ND filter reflected away from the diode. Anyways I did talk about trying with higher power by filter stacking just in case of damaging the filter by starting with a more transparent one which absorbs the least amount of light generating the least heat.

I was thinking of getting one of thsoe models from another place and if yours has a screw on attachment you could rig the filter(s) to that thing

If u wanna talk more in depth let me know ill me around, id personnaly like to know if you get it to work using this idea

500mw divided by 4 = 125mw ND4 filter is the lowest they have from the cheapo 12$ amazon filters

 

[razerizlazer]

Hi there! Thank you for your response. I'm not sure if you've had a chance to check out the website for the IR Laser that I have. In addition, I am using an external plano-convex lens to further reduce the beam diameter. I am wondering if I put an ND filter in front of my IR laser, will it have an impact on the beam size or distance? To clarify, if I put the ND filter before the laser, the IR will pass through the filter first and then through the convex lens. I appreciate your help with this!

 

[Nuguns]

Hi there! Thank you for your response. I'm not sure if you've had a chance to check out the website for the IR Laser that I have. In addition, I am using an external plano-convex lens to further reduce the beam diameter. I am wondering if I put an ND filter in front of my IR laser, will it have an impact on the beam size or distance? To clarify, if I put the ND filter before the laser, the IR will pass through the filter first and then through the convex lens. I appreciate your help with this!

It has no effect on the shape of the beam, it goes right thru. There was a pack of cheap 16$ ND2-ND16 and inbetween, those were melting on contact with my 65mw regular beam size, it made the dot warp quickly. Ive been playing with my ND8 laser with no changes for months now. SO.. if it has an effect on the beam, it will be because of heat doing damage. Ive been nervous to focus the my laser at pin point thru the filter to avoid potential damage, and Ive even accidentally done that twice and it survived with no marks.

Ok here u go, this is the title of the filter I got and vouch for copy paste the bold stuff

the ND4 is now 7$

It sounds really cool what ur doing, I wonder if all those lenses could fit into a portable laser, wouldnt that be so cool. Im having fun imagining your work, would you keep me and us posted with what u got?

ND Lens Filter, for Insta360 GO3 GO2, Waterproof Grey Neutral Density Filter with Balanced Exposure, HD Optical Glass, Nano Coating Technology (ND4)​

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[razerizlazer]

I am using mounts to hold the IR laser pointer and convex lens. The IR beam dia is 3mm and convex lens dia is 25mm.

 

[Nuguns]

the ND filter is about the same size as 25mm, actually less than 20mm. a thought appeared to me, the filter will produce a significant reflection, so it may need housing or a beam stop or something, if u get it.

Youve reached dpss size, nice.

 

[razerizlazer]

the ND filter is about the same size as 25mm, actually less than 20mm. a thought appeared to me, the filter will produce a significant reflection, so it may need housing or a beam stop or something, if u get it.

Youve reached dpss size, nice.

I'm still waiting for the plano-convex lenses to arrive. If they don't work, I might try the ND filter. I'll keep you updated!

 

[Nuguns]

I'm still waiting for the plano-convex lenses to arrive. If they don't work, I might try the ND filter. I'll keep you updated!

those arent gonna dim it tho, but you should know that. Itl make it brighter in a more focused spot, I thought you already had those

All the ND filter is gona do is dim it safely as long as you catch the reflection.

call me confused

 

[razerizlazer]

I am working on an application that requires focusing beams at a single point. Unfortunately, I do not have access to a good optics system, so I have to take a non-traditional approach. I am curious about the results I can achieve with different laser powers, ranging from 100mW to 500mW. That's why I created this post.