Is It Correct To Use or Buy 1mW, 5mW Laser Pointer Only?

46 posts / 0 new
Last post
xephon
xephon's picture
Offline
Last seen: 1 day 6 hours ago
Joined: 04/30/2013 - 07:19
Posts: 69
Location: /ˈsɪŋəpɔr/

The 488nm colour is really nice, anyone knows where to get a good low power 488nm laser pointer for presentation use?

bosummer
bosummer's picture
Offline
Last seen: 11 months 3 weeks ago
Joined: 12/15/2013 - 09:12
Posts: 25
Location: US
xephon wrote:
The 488nm colour is really nice, anyone knows where to get a good low power 488nm laser pointer for presentation use?

I have never used or seen 488nm laser. I am curious with its beam color in presentation.

You will never know how strong you are unless you are in trouble.

hank
hank's picture
Offline
Last seen: 4 hours 44 min ago
Joined: 09/04/2011 - 21:52
Posts: 7241
Location: California

Don’t believe the crap you read from people trying to sell you stuff.

Look it up for yourself and think about whether you’re getting trustworthy information.

Blue light and retinal damage
Blue emission from LEDs

Above, ordinary LEDs; then when you intensify that by what a laser emits:

Specular vs. Diffuse Reflection – The Physics Classroom
www.physicsclassroom.com › … › Reflection and the Ray Model of Light‎
Reflection off of smooth surfaces such as mirrors or a calm body of water
[or shiny metal or glass or plastic] leads to a type of reflection known as specular reflection. …

Laser Safety Training Guide – Princeton University
Apr 9, 2014 – Lasers are classified according to their potential
to cause biological damage. … This includes intrabeam viewing or specular reflections. …

sellialove
Offline
Last seen: 2 years 2 months ago
Joined: 12/16/2013 - 19:44
Posts: 22
Location: Hong Kong
Helios- wrote:
On the one that did 240mW of 532nm, how many mW did you measure including IR? You say the rest was IR, surely not the rest of 1W?

high powered laser pointer might project more invisible ir light. It is not a good choice for new laser users. Do be cautious.

Richwouldnt
Richwouldnt's picture
Offline
Last seen: 2 weeks 6 days ago
Joined: 05/24/2014 - 00:22
Posts: 1324
Location: Reno, NV, USA, Terra, Sol, Milky Way, Known Universe

Green laser pointers are popular for field lecturers in Astronomy as they show up well when pointed into the sky particularly if there is dust or moisture in the atmosphere. Everyone I know who uses them this way is careful to not point at aircraft or at people. The laser pointer I bought for this purpose several years ago was sold as being in the 30mw output power range and shows up very well even in the low humidity environment of Nevada.

Rich Wood
Reno, NV

sellialove
Offline
Last seen: 2 years 2 months ago
Joined: 12/16/2013 - 19:44
Posts: 22
Location: Hong Kong

Green laser pointer with the most sensitvie 532nm green light emitting, is very bright and visible at night.
It is especially suitable for astronomy stargazing.

bosummer
bosummer's picture
Offline
Last seen: 11 months 3 weeks ago
Joined: 12/15/2013 - 09:12
Posts: 25
Location: US

Thanks a lot for your remind. I will try to know more about laser hazards information first. It is very important before really owing a 460nm blue laser pointer.

You will never know how strong you are unless you are in trouble.

Livinloud
Livinloud's picture
Offline
Last seen: 1 year 5 months ago
Joined: 06/03/2013 - 21:03
Posts: 1268
Location: Mass

Btw 532nm or green lasers in general are HORRIBLE for astronomy since they are the brightest and most picked up color by the human eye. Using a green laser is a great way to ruin your night vision/night eyes.

If you arent serious about it then yeah its good since its very easy to see in the sky

LPF Member: Livinloud
Budget flashlight enthusiast turned into lumen freak

Richwouldnt
Richwouldnt's picture
Offline
Last seen: 2 weeks 6 days ago
Joined: 05/24/2014 - 00:22
Posts: 1324
Location: Reno, NV, USA, Terra, Sol, Milky Way, Known Universe

Livinloud wrote:
Btw 532nm or green lasers in general are HORRIBLE for astronomy since they are the brightest and most picked up color by the human eye. Using a green laser is a great way to ruin your night vision/night eyes.

If you arent serious about it then yeah its good since its very easy to see in the sky

I have never noted much effect as long as it is aimed ONLY at the sky and not bounced off of solid objects or aimed at any one, nor used indoors. If it was not visible in air it would be useless as a outdoor pointer for astronomy.

Rich Wood
Reno, NV

Livinloud
Livinloud's picture
Offline
Last seen: 1 year 5 months ago
Joined: 06/03/2013 - 21:03
Posts: 1268
Location: Mass

Not the point. Green is picked up the most by the human eye. You can get a 445nm, 405nm, 638nm or even 660nm that you can see the beam but since the eye doesnt pick up those colors as well, they dont look as bright, thus not altering your night vision as much

Trust me, I build and sell lasers. Green lasers are good for rookie astronomers or people trying to point out things to someone who doesn’t know what they are looking at but if you are attaching it to a telescope then green is not the wavelength you want

LPF Member: Livinloud
Budget flashlight enthusiast turned into lumen freak

Richwouldnt
Richwouldnt's picture
Offline
Last seen: 2 weeks 6 days ago
Joined: 05/24/2014 - 00:22
Posts: 1324
Location: Reno, NV, USA, Terra, Sol, Milky Way, Known Universe

Agreed, not for telescope attachment but used primarily as you say, for pointing out items to people not familiar with the sky as part of lectures. An awful lot of the local astronomy club’s activities are with local schools and other public outreach activities at local and state parks and similar locations. For that type of use you need ready visibility.

Rich Wood
Reno, NV

hank
hank's picture
Offline
Last seen: 4 hours 44 min ago
Joined: 09/04/2011 - 21:52
Posts: 7241
Location: California

http://www.theverge.com/2014/6/27/5848598/russia-goalkeeper-shot-by-lase...

“… green laser pointers such as the one apparently used yesterday can be particularly dangerous for human vision. Green lasers are created using infrared light invisible to the human eye. Many pointers use filters to stop this light from reaching us and damaging our vision, but some cheaper devices have no such filter.

One study from the National Institute of Standards and Technology and the University of Maryland showed that one $15 pointer kicked out 10 times more IR light than green light — enough to damage the eye before a blink response.

Livinloud
Livinloud's picture
Offline
Last seen: 1 year 5 months ago
Joined: 06/03/2013 - 21:03
Posts: 1268
Location: Mass

99% of people are uninformed when it comes to lasers. Funny part is that the eye can take a lot more IR light then visible light before damage occurs. IR disperses more over the eye than say 532nm thus it can take a higher amount HOWEVER I DONT RECOMMEND IT and personally I use safety glasses whenever indoors

LPF Member: Livinloud
Budget flashlight enthusiast turned into lumen freak

hank
hank's picture
Offline
Last seen: 4 hours 44 min ago
Joined: 09/04/2011 - 21:52
Posts: 7241
Location: California

http://www.technologyreview.com/view/420214/the-danger-of-green-laser-po...
——quote——

… a simple way for anybody to detect these infrared emissions.

The method is to reflect the the beam off a standard CD which acts as a diffraction grating, and so separates light of different wavelengths. The diffracted light is reflected onto a piece of paper which displays the diffraction pattern. Many webcams are sensitive to infrared light or can be easily modified to detect it. So photographing the paper using such a camera shows the diffraction pattern of the green light and any infrared light produced too.

The team hasten to emphasize the safety procedures that must be used during such an experiment.

They also take apart the green laser pointer in question to identify the cause of the problem. The design ought to include an infrared filter that blocks any infrared light that isn’t converted to green light. However, the culprit they bought not only did not have the filter, it did not have a slot for such a filter. “We thus believe that the absence of the filter in this case was due to a design decision,” they say

So somebody somewhere has removed the filter from the design, presumably to reduce costs. If that isn’t a criminal act, it ought to be.

Ref: arxiv.org/abs/1008.1452: A Green Laser Pointer Hazard

hank
hank's picture
Offline
Last seen: 4 hours 44 min ago
Joined: 09/04/2011 - 21:52
Posts: 7241
Location: California

https://phys.org/news/2017-10-unwittingly-dangerous-laser-pointers-scien...

Quote:
: … “Our main concern is laser pointers which seem safe to the user but are in fact very powerful. These lasers can lull people into a false sense of security and lead to injury.

“Some lasers that are labelled as safe turn out to be highly dangerous because they can emit highly powerful invisible laser light. Moreover, the visible laser power can vary a lot, depending on temperature.

“Other labels are mistaken, and the maximum power output of the laser is often higher than the safety class on the label, again putting the user and others in danger.”

Dr Valev and PhD student Christian Kuppe in the University of Bath Department of Physics, collaborated with Dr Dimitar Slavov from the Bulgarian Academy of Sciences to develop scientific equipment for carefully testing the laser diodes in the heart of every pointer.

“Our results show that the so-called ‘frequency doubled’ laser pointers, usually green, blue and violet pointers, can be particularly dangerous even if they seem safe to the user,” he said.

“For example, some laser pointers can output widely different laser power depending on the temperature. They can appear perfectly safe at room temperature only to become much more dangerous outside and vice-versa. Moreover, as pointers are being used they heat up, so a pointer that initially seems safe can subsequently become highly powerful and dangerous.

“Other lasers can produce safe levels of coloured light, but at the same time emit high power invisible infrared light. A person looking at the visible green light would estimate the laser to be safe and the much greater power and danger would go unnoticed until injury occurs….”

Read more at: https://phys.org/news/2017-10-unwittingly-dangerous-laser-pointers-scien...

and see the related stories at the bottom of that page:

Quote:
The Medical Minute: Solar eclipses and laser pointers pose similar eye hazards August 22, 2017

Much attention is focused on the potential dangers that the upcoming solar eclipse will pose to the unprotected eye. But health experts caution there’s at least one other—and more prevalent—way to do lasting damage …
————————————-
That laser pointer could be more dangerous than you think December 1, 2015

Lasers are rapidly getting cheaper, smaller and better. …

————————————-

Over-the-counter laser pointers a threat to eyesight August 18, 2016

Laser pointers bought legally for less than $AU30 are a threat to eyesight – with one pointer found to be 127 times over the Australian legal limit.

Read more at: https://phys.org/news/2017-10-unwittingly-dangerous-laser-pointers-scien...

Pages