Why do I see a apeckle pattern in laser light ?

[partylighter]

When I point my laser pointer (regardless what color) at a bright surface, the bright spot reflects and acts as a bright light source.
But the area illuminated by the laser has a strange speckle pattern. No, there is no error in my eyes as I see the same surface when illuminated by an incandescent / fluorescent / led lamp woth the same color without these speckle pattern.

Why this speckle pattern ?

 

[Jimmymcjimthejim]

Destructive Interference

 

[pullbangdead]

Speckle pattern - Wikipedia, the free encyclopedia

 

[daguin]

Speckle pattern - Wikipedia, the free encyclopedia

You are a research BEAST! :bowdown:

Peace,
dave

 

[pullbangdead]

You are a research BEAST! :bowdown:

Peace,
dave

:yabbem: ::embarrassed::

 

[daguin]

You are a research BEAST! :bowdown:

Peace,
dave

:yabbem: ::embarrassed::

I think mostly only post-graduate students will understand :beer:

Peace,
dave

 

[bloompyle]

I think mostly only post-graduate students will understand :beer:

Peace,
dave

I might be wrong, but I think he was mocking you for using wikipedia, hell a dog with the ability to type could have information there. Unless it's not spam, it stays on there lol.

 

[daguin]

I might be wrong, but I think he was mocking you for using wikipedia, hell a dog with the ability to type could have information there. Unless it's not spam, it stays on there lol.

PBD is a graduate student. I am a professor. He is well aware of the sarcastic intent of my comment

Sarcasm -- Just one of the services I offer :angel:

Peace,
dave

 

[Xplorer877]

PBD is a graduate student. I am a professor. He is well aware of the sarcastic intent of my comment

Sarcasm -- Just one of the services I offer :angel:

Peace,
dave

What college do you teach at Dave?

Even a surface that appears and feels smooth, at a microscopic level, it is actually rough and pours. If those pores are larger than the wavelength of the laser, they get diffused and reflected at odd angles.

-Tony

 

[daguin]

What college do you teach at Dave?

Even a surface that appears and feels smooth, at a microscopic level, it is actually rough and pours. If those pores are larger than the wavelength of the laser, they get diffused and reflected at odd angles.

-Tony

I am at East Los Angeles College. I also pick up classes at Cal Poly Pomona and Mt. San Antonio College when the economy is better

Peace,
dave

 

[Xplorer877]

Aww too bad you aren't teaching at UCSD, I'd take your class. But they seem to love you on Rate My Professor. Haha!

-Tony

 

[daguin]

Aww too bad you aren't teaching at UCSD, I'd take your class. But they seem to love you on Rate My Professor. Haha!

-Tony

Sites like "RatemyProfessor.com" and "Whototake.com" generally show a bi-modal response spread. The only students who take the time to write something are the ones that really like the professor or really dislike the professor. The vast majority of students fall into the "I thought my professor was about 'normal'" range.

This overwhelming majority do not take the time to report anything.

They are fun to read though

Peace,
dave

 

[Xplorer877]

Well I think that is a good thing. You surly have seen your fair share of stupid lazy student's who hate YOU for failing them. It's your fault they got an F. LOL. I could care less what they think. It's like when I was looking up my Calc III professor, all the students who claimed that he failed them were taking Math 100.... pathetic. I ignore those reviews. It's clear that they hate math, not the teacher. See my point?

-Tony

 

[Benm]

Sites like "RatemyProfessor.com" and "Whototake.com" generally show a bi-modal response spread. The only students who take the time to write something are the ones that really like the professor or really dislike the professor. The vast majority of students fall into the "I thought my professor was about 'normal'" range.

I suppose that is universal of any website that reviews whatever subject. People that post are either disappointed or very well pleased. The whole group that things something/one 'works as expected' has little voice.

Then again, many professors are quite average too - i've had some very good and very poor ones over the years in university, but in the end i suppose i would rate 90% of them as 'okay' and nothing to write home about.