Question on laser reflection (pic included)

In summary: Thanks for the great advice! I'll definitely try that next. In summary, the lasers displayed an exceedingly wide range of brightness, with the green laser exhibiting the greatest increase. This could be due to a smudge or dirt on the lens of the green laser, or a difference in the camera's sensitivity to green light.
  • #1
TRB8985
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Good morning all,

I'm currently working in some undergraduate research involving lasers and recently had the opportunity to play around with a few that my research professor has at our disposal. I've included a picture below of a strange phenomenon that has me a little puzzled, but then again I haven't taken any optics courses.

https://scontent-ord1-1.xx.fbcdn.net/hphotos-xat1/v/t1.0-9/12509680_10156372942255580_8733921899061724202_n.jpg?oh=6d59dee08a311015be6e8811bd211c64&oe=573793A9

While the quality of the image isn't the best, what I've done is place the outputs of three 90 mW lasers of 656 nm, 532 nm, and 405 nm up on a wall located in a room with very little to no textural disturbances on the surface of the wall. I can't seem to understand why the green laser would have such an enormously wide output compared to the two others.

Is there a property in optics that might explain this? I thought maybe diffuse reflection would be greater for longer wavelengths or something along those lines, but the red laser would have to display that property too, so I'm a little stumped.

Any ideas?
 
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  • #2
TRB8985 said:
what I've done is place the outputs of three 90 mW lasers of 656 nm, 532 nm, and 405 nm up on a wall located in a room with very little to no textural disturbances on the surface of the wall. I can't seem to understand why the green laser would have such an enormously wide output compared to the two others.

Question to you
was this extra brightness just visible in the camera image ? or visible directly by eye as well ?

There are some significant reasons ...
... ohhh and to help you in your quest ... google search eye and digital camera sensor sensitivitiesDave
 
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  • #3
Hey Dave,

This extra brightness was also visible via the naked eye as well, and is especially more pronounced. Unfortunately, none of the crazy reflective detail translated to the photo.

Thanks for your recommendations!
 
  • #4
First thing I would do is make sure the lens on each laser is clean and free of smudges, dirt, etc. It could be something as simple as a smudge on the green laser that's causing it.
 
  • #5
Or batteries?
 
  • #6
Humans eyes have their sensitivity peak around green, while 405 nm is at the edge of the visible range and the sensitivity for 656 nm is worse as well. That explains a large part of the observed difference. Cameras are more sensitive to green light as well to improve image quality, but image processing takes care of this.
 
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mfb said:
Humans eyes have their sensitivity peak around green, while 405 nm is at the edge of the visible range and the sensitivity for 656 nm is worse as well. That explains a large part of the observed difference. Cameras are more sensitive to green light as well to improve image quality, but image processing takes care of this.
yes and this is what I was wanting the OP to google research on and he would have discovered that :smile:Dave
 

1. What is laser reflection?

Laser reflection is the phenomenon of light bouncing off a surface at an angle equal to the angle at which it initially hit the surface. It is a result of the law of reflection, which states that the incident angle is equal to the reflected angle.

2. How does laser reflection work?

Laser reflection works by directing a beam of coherent light onto a surface at a specific angle. When the light hits the surface, it is reflected off at the same angle, creating a mirror-like effect. This is due to the light's wavelength and the smoothness of the surface, allowing for minimal scattering or diffraction.

3. What factors affect laser reflection?

The factors that affect laser reflection include the angle of incidence, the smoothness of the surface, and the wavelength of the light. The angle of incidence determines the angle at which the light will be reflected, while the smoothness of the surface affects the amount of scattering and diffraction that may occur. The wavelength of the light also plays a role, as different wavelengths can be reflected differently depending on the material of the surface.

4. What are the applications of laser reflection?

Laser reflection has many applications in various fields such as optics, electronics, and telecommunications. It is used in laser-based technologies such as laser cutting and welding, barcode scanners, and laser printers. It also plays a crucial role in fiber optic communication systems, where laser light is reflected off mirrors to guide the light through the fibers.

5. Can laser reflection be controlled or manipulated?

Yes, laser reflection can be controlled and manipulated by adjusting the angle of incidence, changing the properties of the surface, or using specialized mirrors. This allows for precise control of the direction and intensity of the reflected light, making it a valuable tool in many scientific and technological applications.

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