Help in buying appropriate lasers

[TheScientist]

Hi, all,

I'm not a laser enthusiast as many of you are but I'm interested in using them for a project. I am a (real) scientist attempting to conduct a vision study with animals and want to use lasers as a sort of vision-only obstacle course. We're using 532 nm because we know that is in the range of what these animals can see (blue/violet is a possibility; red is out). For this to work, the beam needs to be visible in the dark. I've just tested out a 50 mW laser and the beam is weak and barely visible even to me. Is the solution to increase power? I am concerned about the safety of eyes and skin for the animals, so am worried about lasers strong enough to light matches and pop balloons. Does anyone have any suggestions for increasing beam perceptibility? I've considered smoke/fog, but there is a lot of sensitive equipment in the room that might suffer damage.

 

[steve001]

Hi, all,

I'm not a laser enthusiast as many of you are but I'm interested in using them for a project. I am a (real) scientist attempting to conduct a vision study with animals and want to use lasers as a sort of vision-only obstacle course. We're using 532 nm because we know that is in the range of what these animals can see (blue/violet is a possibility; red is out). For this to work, the beam needs to be visible in the dark. I've just tested out a 50 mW laser and the beam is weak and barely visible even to me. Is the solution to increase power? I am concerned about the safety of eyes and skin for the animals, so am worried about lasers strong enough to light matches and pop balloons. Does anyone have any suggestions for increasing beam perceptibility? I've considered smoke/fog, but there is a lot of sensitive equipment in the room that might suffer damage.

I doubt you are a professional scientist. What are your credentials? I'm giving you the chance to provide proof, please take it.

 

[TheScientist]

I appreciate your skepticism, but I'm not about to disclose my identity on an internet forum by uploading a copy of my certificates or transcripts. I am a graduate student (MS received, PhD in progress), studying sensory systems at a university (I'm a biologist, not a physicist). However, me telling you that is to provide context to my question. The question on its own is valid: how do I increase beam visibility? I am asking here, not because I'm a sketchy imposter, but because there are thousands of people here who have experience using a variety of products. If I wanted the mathematics of optics, I'd go next door to the physics labs.

 

[NightExplorer96]

Hmmm... using a fog machine would have been my first choice to increase beam visibility, but I see this isn’t going to work for you. Only other option I can see is to increase power but as you’ve said, this is getting into dangerous territory with animals and burn/eye hazards.

What kind of laser was the 50mW 532? Was it a cheap pen laser or more of a professional laboratory style laser? A stable, laboratory 50mW 532 should have a pretty good beam at night which is why I’m wondering. A cheap pen 532 would most then likely not hold a stable 50mW’s. :yh:

-Alex

 

[RA_pierce]

... I'd go next door to the physics labs.

Why not go to the physics labs and ask for advice, then? They probably have some lasers for you to look at, somewhere.

Also, you haven't provided enough information for us to help you.
Why do you need a laser and why will LEDs or colored objects not suffice?
It seems, based on your description, that a narrow spectrum is not important so long as it is visible to your study animals, so I don't see why you need a laser for this.

If you want something that is safe for human vision, read up on the FDA compliance standards for lasers. 5mW is the limit for use without safety eyewear but will not produce a visible beam without smoke/fog in the air and dark conditions. If you are hoping for a visible beam without any fog, you will want a laser producing several watts - a serious eye injury and fire hazard.

- Sincerely,
Another (real) scientist

Edit: After re-reading your post, it sounds like your intention is to make some sort of maze with a laser beam. This seems like a terrible idea. Even 5mW is not safe for direct exposure to the eyes and there is a good chance that your insects or mice or whatever, will accidentally cross the beam at some point. Find a different way to conduct your study. Lasers are really not practical tools for most jobs.

 

[Radim]

I appreciate your skepticism, but I'm not about to disclose my identity on an internet forum by uploading a copy of my certificates or transcripts. I am a graduate student (MS received, PhD in progress), studying sensory systems at a university (I'm a biologist, not a physicist). However, me telling you that is to provide context to my question. The question on its own is valid: how do I increase beam visibility? I am asking here, not because I'm a sketchy imposter, but because there are thousands of people here who have experience using a variety of products. If I wanted the mathematics of optics, I'd go next door to the physics labs.

Well, tell us more about the project. If we do not know sufficient details, how can we help you? Put images, sources, make a nice post here about your project and enjoy people here providing you the best advice you could get here. Without proper discussion we could just assume. I'm studying sensory system as well. However I'm philosipher, not limited only to biology. You could even bring some insights to others and improve your project. Mutually improving. This is not just forum, it is base of world wide laserists community with extremely broad scope. Just use the asset you found on internet and get it serious (as scientists do).

Really no need for ID here. Just put your location (country and/or city) to help community to direct you. Who knows, maybe you live next doors to someone who could actively help you with your experiment.

And welcome.

 

[GSS]

I'm curious why the beams need to be seen, wouldn't just the spot be ok?

 

[TheScientist]

The reason I need lasers and not colored objects is because objects are solid. I do not want the animal to use any other sensory information but the laser beam. A dot doesn't work for this purpose because then it's just a two dimensional image. And I do understand the different safety classifications for lasers, but I'm trying to expose my animals to the minimum amount of danger while still achieving the goal; it doesn't have to be 'safe', just 'safe as possible'. And as other researchers are aware, funding is scarce and I need about 40 of these, so spending thousands per laser is just not feasible. The 50 mW tested was from laserpointerpro and was about $50. I've found some other reasonably priced ones that seem like better quality, but most won't ship to the US.

So for those of you suggesting a different type of study: what would you recommend. I need a three dimensional obstacle that gives only visual feedback. Nothing they can feel, smell, or hear.

 

[RA_pierce]

So for those of you suggesting a different type of study: what would you recommend. I need a three dimensional obstacle that gives only visual feedback. Nothing they can feel, smell, or hear.

If you must, I would recommend you use a low power 1-5mW green laser and find a way to enhance visibility a closed area (so that your equipment isn't affected). If you do use fog, it may have some effect on the study animals so you will have to consider what is the best way to increase visibility with minimal impact on the experimental design. I'm not sure what this would be.
Water vapor may be an alternative to kerosene fog but does produce a lot of condensation. Dry ice and a fan to circulate the vapor could work but it may sedate your animals.

To avoid buying so many lasers, you can use mirrors to bounce the beam around. First-surface mirrors will maintain the beam better than second-surface mirrors (which are cheaper but produce multiple reflections due to the glass surface).
I would recommend a bench-top laser as these will be more stable and don't depend on batteries. I'm thinking something like this:
12 mm Green Laser Module - Z-Bolt&reg Certified Class 11, <1mW, 100 mm Leads or Spring

If you go with something more powerful, there is a chance that the animals will be able to feel the laser, especially at 50mW or more.
The issue with lasers or any high-intensity light source is that if your experimental design damages your animals' eyes, it will impair the sensory system you are trying to examine.

Because this isn't my experiment, I'm not going to think too hard about it. I don't know what you are trying to test or the best way to do it given your study system.
There may be another experiment that will give you equivalent information. We can't figure that one out for you, so I hope the laser advice is somewhat helpful.

 

[Radim]

I'm curious why the beams need to be seen, wouldn't just the spot be ok?

Not sure. However animals see diferently than people (some completely, some slightly). Depending on animal under experiment and experiment itself wavelength and power should be selected. You know my encounters with the deer alpha male in dark night forest and freezing feelings during laserpaintings, when I'm deep down in art creation world and aware the wild and ready to attack deer is there. Definitely 100 mW 532 nm made him crazy and saved my butt from being penetrated by his antlers.

For OP: I found one of my older posts related to animal vision (just for context):

https://laserpointerforums.com/f44/...ers-yamataka-series-100957-2.html#post1486370

I've no doubt Arctic is the most powerful laser. They claimed it, it must be truth. :crackup: (Disclaimer for those not aware and/or realizing we are joking here: Arctic is not the most powerful laser, even mine peaks nearly 4 W, there are 7 W diode lasers commercially available.)

Photosynthesis uses light absorbed, CO2 and water to build plant/tree structures. Since all visible part except green is absorbed this explain the green color of leaves, there is chlorophyll responsible for that:
https://en.wikipedia.org/wiki/Chlorophyll

This is absorption spectrum of chlorophyll A and B. Source is wiki - the link above.

My hypothesis is as wild animals, like deers, live in green environment their eyes are evolutionary adapted to be sensitive for spectre common in this environment to spot predators hidden in vegetation and terrain and run away (those with lack of this advantage were killed by predators before they were able to reproduce, those with this ability had higher chance to survive), also there might be effect of better ability to recognize various edible plants by slightly different color from those with poissoned and not tasty (?). Also plants are know to reflect ultraviolet, so here it also plays role. Also the active time of the day influenced eye evolution and that's why they are much more light sensitive than human.

Check out this:
How Game Animals See & Smell | ?????????? ????????? ?????? HUNTER.RU

Source is the link above.

As a consequence of high (and much higher than human eye) sensitivity to blue - green the bright laser dot therefore is something unknown and animals are led by instinct to escape from unknown and likely dangerous stuff. (I even bet it is a bit painful for them to see green/blue dot at dusk or near sunset.) I think also blue laser will work well, but red won't be much effective (as well as yellow and orange). Interesting is the sensitivity in UV and the shift of peak to blue compared to human eye sensitivity. So, they can even spot you when you think you are not visible, but because your clothes were washed in some detergent it will glow for them much more than human can see as the detergent fluorescent spectre is highly visible for them. So you will look blue in green vegetation to them even human won't see you due to camuflage and lack of sensitivity for that part of spectre.

Here for more:



Source: https://en.wikipedia.org/wiki/Optical_brightener

And here interesting article (images below are sourced from the article):
Washing ACU, Army Combat Uniform

 

[steve001]

I appreciate your skepticism, but I'm not about to disclose my identity on an internet forum by uploading a copy of my certificates or transcripts. I am a graduate student (MS received, PhD in progress), studying sensory systems at a university (I'm a biologist, not a physicist). However, me telling you that is to provide context to my question. The question on its own is valid: how do I increase beam visibility? I am asking here, not because I'm a sketchy imposter, but because there are thousands of people here who have experience using a variety of products. If I wanted the mathematics of optics, I'd go next door to the physics labs.

We get a fair number of trolls and your post had that troll ring to it.
There's only one way to increase the visibility of visible light in this case. It must pass through a material which scatters light. That's the first problem you have to solve.

 

[paul1598419]

I agree with steve on this one. It doesn't sound at all like the types of experiments we did in a university setting and sounds more like someone's hypothetical wet dream.

 

[Encap]

The reason I need lasers and not colored objects is because objects are solid. I do not want the animal to use any other sensory information but the laser beam. A dot doesn't work for this purpose because then it's just a two dimensional image. And I do understand the different safety classifications for lasers, but I'm trying to expose my animals to the minimum amount of danger while still achieving the goal; it doesn't have to be 'safe', just 'safe as possible'. And as other researchers are aware, funding is scarce and I need about 40 of these, so spending thousands per laser is just not feasible. The 50 mW tested was from laserpointerpro and was about $50. I've found some other reasonably priced ones that seem like better quality, but most won't ship to the US.

So for those of you suggesting a different type of study: what would you recommend. I need a three dimensional obstacle that gives only visual feedback. Nothing they can feel, smell, or hear.

First off laserpointerpro is a garbage Chinese laser web site that typically misrepresents every laser they sell and overcharges as well. Nothing you will ever get from them is what what say it is nor reasonably priced.

Second you need to understand that there is no visible beam from a laser of any power 1mW or 1MW in a vacuum.
You don't ever see a laser beam, you just see reflections from particles in the air the beam hits.

Whether or not you can see the beam or the extent to which you can see a beam depends upon many things -- among them the position of the observer in relation to the source of the beam, amount of aerosols/particles in the air reflecting light to an observer, an individuals eye sensitivity to any given wavelength.

At sea-level, one cubic inch (1 inch x 1 inch x 1 inch) (16.39 cm3) of "air" contains approximately 400 billion billion air molecules, each moving at about 1600 km/hr (1000 miles/hr), and colliding with other molecules and anything else they come into contact with about 5 billion times per second. This is the reason for "air pressure".
The amount of particles in that air that can reflect a portion of a laser beam's light back to your eye determines if you can see it or not and the degree to which it is visible

The key piece of technology that will enable your envisioned experiments obstacles system to exist and function only exists in your imagination.
Everything is possible in imagination, not so in the real world.

We get a fair number of trolls and your post had that troll ring to it.
There's only one way to increase the visibility of visible light in this case. It must pass through a material which scatters light. That's the first problem you have to solve.

Exactly--well said.

I agree with steve on this one. It doesn't sound at all like the types of experiments we did in a university setting and sounds more like someone's hypothetical wet dream.

Yes sounds like a grade school level daydream --- ill conceived and flawed in several ways.

 

[cyberdoc]

On what basis did the OP chose the laser wavelength? One can’t accurately determine an organism’s visual sensitivity from anatomy alone. Vision is a highly complex sense, involving far more than just the numbers of rods and cones. Color discrimination studies need to be done before choosing appropriate wavelengths. The spectral diversity of cheap lasers makes it necessary to use expensive laboratory grade lasers. Thanks & Take Care.

-cd

 

[lasersbee]

Hi, all,

I'm not a laser enthusiast as many of you are but I'm interested in using them for a project. I am a (real) scientist attempting to conduct a vision study with animals and want to use lasers as a sort of vision-only obstacle course. We're using 532 nm because we know that is in the range of what these animals can see (blue/violet is a possibility; red is out). For this to work, the beam needs to be visible in the dark. I've just tested out a 50 mW laser and the beam is weak and barely visible even to me. Is the solution to increase power? I am concerned about the safety of eyes and skin for the animals, so am worried about lasers strong enough to light matches and pop balloons. Does anyone have any suggestions for increasing beam perceptibility? I've considered smoke/fog, but there is a lot of sensitive equipment in the room that might suffer damage.

1) If you need to tell us that you are a REAL scientist
my BS meter goes off....

2) My cats have no trouble at all seeing a <5mW Red
Laser.

3) Use a <5mW Laser and your Laser Safety Concerns
are covered or put Safety Googles on your Animals and
"scientists" in the room.

4) You need to put particulate into the air for the Laser
beam to reflect off of if you want to see the Beam.

5) Move to a different room without the Sensitive
Equipment in it.


Jerry

 

[Cyparagon]

A beam of light is not an obstacle. If you can train these animals to avoid light in front of them, I don't see why you couldn't light up the "floor" with LED tape instead.