Recent content by opr

This is a great chart. Thanks. I thought buying a blue laser. But according to this chart, there is no point if the purpose is to point on distant objects.

Yep. I also think that the pupil computation is irrelevant. Here is the link to the graph I used as reference, in case someone missed it. According to the author of the graph, it is based on IEC 60825 formulas http://commons.wikimedia.org/wiki/File:IEC60825_MPE_W_s.png

I was just curious to see how a laser looks from a large distance. Can it be seen? Can it be seen from 5 km? All this laser stuff is not very practical. It is just pure fun to experiment with it.

Unfortunately, you have a mistake in a factor of 10. 0.1mw/cm2 = 0.001mw/mm2 (You have to divide by 100) Lets stay in cm. According to Wikipedia, when the pupil is max opened it is 4-9 mm. Let’s take 9 mm which is 0.9cm. So the power entering the eye with blue laser is: (0.9/2)^2*pi*0.8=0.5mw.

Hi Atomicrox. I thought I miscalculated something, so I delete the message. But eventually it was ok. I added a short distance calculation. There is a huge difference as you can see. Short distance is very dangerous.

Ok. I did some research and learning. And here are my conclusions: Let’s talk about a super high quality laser as an example, with the following spec: Green laser -200 mw -Beam diameter - 1mm (Typically it is 1.5mm and above) -Divergence 0f 0.5mrad (Typically it is 1 and above for Green laser)...

I want to test how the laser looks from a distance. Can pointing directly on someone from 1Km with 200mw Green laser do any damage? (Lets say I mesured the distance with Google earth before trying). Same for 1w Blue laser?

Thanks. that explains it.

I would agree if there were any source of Red light. But there is no Red light to reflect. I did the experiment in the dark. The only source of light was the Green laser. Other Red stuff I point on, just reflect the Green as is in some kind of reduced power. Can it be that a piece of plastic...

A strange phenomenon I don’t understand: I have a green laser. To my understanding, it produces pure green 523nm light. There is a reddish plastic that while pointing the laser to it, converts the Green dot to be Yellow. I can’t understand where this yellow color comes from. I would expect Green...

Hi Eudaimonium Thanks for your answer. If I understand you correctly, you say that It is a normal behaviour for a 200mw laser to reduce its power while it warms. Is it some kind of protection? Does yours act the same?

Some news. Susie just wrote me as follow: Hello Sure we test output power and make sure it is in specification But our laser has duty cycle ,you'd better light it 20 seconds on and then 3 minutes off If so, it is a completly useless laser.

I don’t really know. In the laser page there is no such thing. (Power Rock Green laser Torch 200mW /Focusable&Waterproof [OLPRGL200] - $132.99 : Zen Cart!, The Art of E-commerce) And in fact this is the reason I choose o-like. Since I thought there is no Duty Cycle. But after more research, I...

Thanks for your answer, RA_pierce. I tried fresh charged batteries, and it is the same. I believe it is related to some kind of warming of the laser. The main question: Is it normal for such laser to reduce the power in time? Or is it a faulty laser?

Hi all. I am a newbie and first I want to thank this forum for all the interesting posts I read here. After reading all kind of recommendation, I ordered a 200mw Green laser from O-Like. The main purpose of this laser is as an astronomy pointer. The main issue I face is that after 2 minutes...