Lasers?
If you have to ask, you wouldn't understand.
Since I was a kid and wrote a report for science class about it, I've been fascinated by the laser.
Not too long ago, only scientists in labs had access to them, and they required bench space and quite a bit of AC power.
I recall my early sketches of ruby rods surrounded by bright light "chargers" and only imagined.
Your average laser pointer (like we play with in conference rooms or to tease the cat) has power output of less than 5mW (1 milliwatt is 1/1000th of a watt),
which is still relatively safe to look at, and is what you often see used at concerts and such events.
A coherent beam of light at a wavelength of 532nm (nanometers) is such that we can see it even in daylight.
Hence, green lasers are popular because you can see the beam itself, not just the dot on a surface where it ends.
Other colors can be seen, but may require smoke, fog or particulates in the air. Some lasers emit light you cannot see at all, such as infrared (IR).
All can emit dangerous radiation. LASER (Light Amplification through Stimulated Emission of Radiation) light is the energy of very excited atoms and potentially extreme heat, not just visible photons.
Portable Lasers
I acquired my first "real" laser in October 2009. It's a 532nm class III-b green RPL (Rechargeable Portable Laser).
With average output power of >420mW, it is capable of burning things, and the beam is visible in a lighted room (even at low power) as well as outdoors at night.
With a very minimal beam divergence, it can reach distances of many miles, as its class is often used for such jobs as aligning microwave antennae.
My second high quality laser (bought in December 2009) is a 473nm class III-b blue RPL.
With average output power of >30mW, it is not capable of burning things.
The beautiful blue beam is visible in a lighted room as well as outdoors at night. It also has a very minimal beam divergence.
I also have another 532nm class III-b green laser, which is smaller and easy to just grab and "play with".
This one was a discounted purchase through a "group buy" with other members of a laser forum.
With output power of 130mW, it too is capable of burning things, and the beam is visible in a lighted room. This one runs on standard AA batteries.
More Pics
A few photos of my lasers. Click an image for a larger view.
Please note that lasers such as these are not toys! Never point a laser at anyone. Never point a laser at any aircraft!
Images are posted below as I experiment with these awesome instruments and share the beauty of this light fantastic. I'll update this page periodically as interests dictate.
If you would like to learn about lasers, laserpointerforums.com is an extremely useful and objective forum with a lot of information, many experienced users and builders, and topics from the simple FAQ, reviews, DIY forums and much more, including companies where you can buy lasers of many power levels and styles. Be aware that there is some misleading information too, some very young members (kids), and opinions that may lead you to cheap junk rather than good quality. However, if you're careful, you can find reliable info, and learn about laser safety, too.
Optotronics has earned and deserves a great reputation for awesome customer service and quality lasers.
Keep lasers safe and legal!
Demonstrations
Images of laser beams and experiments. Click an image for a larger view.
Simple "beam shots", when I first got my green RPL. These were taken in my office with daylight. The laser is set at the lowest power (1 of 9), and the camera ISO at 800 (no flash, duh).
The blue LEDs on the Beast are a nice setting, and the brand of DVD-RW is fitting, eh? A friend had given me the Obiwan figure years ago. He seemed concerned. I also aligned the beam upon the base of a crystal sphere. Dazzling effect. The intensity made the grey carpet appear brown in the photo.
Some "burn shots". This is not a priority for me (not why I want a laser), but a popular topic on the forum is about burning stuff. So, let's see..
I set the laser on power level 3 for these tests, and set it about 5 feet from the target. I laid a towel on the counter to eliminate the surface reflection, and set the ISO on the camera down to 400.
One thing that affects a laser's burn is the color of the object (how it absorbs light/heat). I tried several colors of paper first. Oh, by the way, yes it does burn your skin (stings very quickly). I did not hold my hand there and grit my teeth to see how long I could take it.
The black was also my backdrop, a thick folder. After a few seconds, it began to smoke, and a small hole appeared. Next were colored post-it notes: The purple burned through in about 1 second, the red even quicker, the yellow took about 3 seconds. The green did nothing but reflect intensely, as did the ordinary white paper. The intensity of the light is such that it's difficult to see the color of some paper.
Black
Purple
Red
Yellow
Green
White
Lets try an onion (because it's handy here in the kitchen). Then, the proverbial question, will it light a cigarette? The onion did nothing but reflect intensely (more so than the white paper).
Onion
Cigarette Yes, it does, but I think I'll just flick my Bic.
Some "optics" experiments. In these experiments, I arrange optics such as lenses and mirrors and play with the beam! This is a lot of fun, and the effects are often a mix of "hmmm, boring" and "ooh, very cool". The variations are endless, and I haven't even tried all of the lenses and prisms yet. I try different things, take a lot of trial and error photos, and select the most interesting for these posts.
This set involved aligning tiny mirrors so that the beam made two right angles and ended around the wall behind the laser. Each is from a different angle. In the fourth, I moved one mirror to create a zig-zag.
The next two are of the beam through a diffraction grating, which splits the beam into many, also reflecting some back.
The next two are of the beam through a convex lens, which magnifies the beam. The closeup is beautiful.
These three are of the beam straight through the center of the crystal sphere. The effect here is awesome, I think. The 3rd of this set shows how the beam "blooms" when it exits (from the front).
When I got the blue RPL, I got these shots by aligning two mirrors, a prism, and a cracked marble. The beam hits one mirror, then the 2nd mirror, then the prism, which splits the beam and sends one beam into the cracked marble. I did this with the green RPL also. Then I recreated the zig-zag effect with both the green and the blue.
Conceptual Laser Imagery
These images are in my Art Gallery (have you seen my gallery?)
I was daydreaming about things to do with lasers, and these concept images arose. I modeled my RPL, worked within my 3D office space, and came up with these "shots".
As part of the ideas behind these concepts, I recall a science kit I had as a child with a small parabolic reflector. It had a small attachment with a holder at the end which, when it was pointed toward the sun, was the focal point of the sun's rays. You could put items such as bits of paper in the holder and they would catch fire. That being said...
First, I built 3 powerful portable lasers. One green, one blue and one red. The output power of each is more than a half watt (>500mW).
I designed these nifty tripods, with swiveling telescopic legs and four-ped rotating feet. The mounts are a ball and socket, which have a hole wherein the clamp mounts plug. This provides a wide range of positions for whatever is mounted, such as an RPL as seen in the first image.
In these next shots, my mini workbench. It has two tracks, into which mounting assemblies can slide along with attachable dollies. Each dolly grips the center of the track and has a wheel for precise horizontal movement along the track. This bench allows a wide variety of configurations. For the following, I have mounted a large parabolic mirror, and another mount has sliding vertical and horizontal (perpendicular to the track) adjustments. The second mount has a cracked marble mounted in a clamp, centered in front of the mirror.
This conceptual instrument contains a super clear glass rod, fed by three polished prisms, each having two planes exposed. The rod has a 100% reflective mirror on the rear and a partially reflective mirror on the opposite, behind a collimating lens. The idea is to capture and collimate already high energy laser light, without needing a power supply to produce new excited photons within the rod. One shot shows the assembly disconnected and partially pulled from the tube.
While precise, there are a lot of beams flying around in these next shots. With all the laser light and reflections, the intensity and brightness is apparent. Beam visibilty of all wavelengths is enhanced by all the cigarette smoke introduced into the scene during project development.
For my first experiment, I set the lasers so that all three beams align on the mirror to focus on the marble. The effect is intense, and the marble glows so brightly that it appears white.
Here, I mounted the rod centered in front of the mirror. The concept here is to produce a white laser by combining and collimating the light energy from the three lasers into one white beam. Each laser is focused via the mirror toward one of the prisms. You may have noticed the mirror has an opening in the center. The white beam is directed through the center. This beam is not as hot as any one of the portables.
As I complained about after another project (before I got my lasers), I'm always finding these guys screwing around with my stuff!
Just for fun, animated laser-related imagery from my Art Gallery
Play part 1
Play part 2
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