Reflection of Laser Beam

Look ip "retroreflectors", "reflex" reflectors and "mircospheres". Also look up "galvano" process to see how they make reflex items.

These are all capable of reflecting low power light signals back along the line of incidence so that the beam comes back to your source. They are made from multiple materials and you would already see many of them in use.

They are used on roadside markers to reflect your headligths back to you, similarly on th erear of cars and many roadsigns.

I know that 3M had an adhesive backed tape that used microspheres around 5 years ago. We used that for distance and intensity measurement (calibration) in a laboratory. The stuff was very stable compared to plastic lenses that had been used previously.

Many of the clear plastics are also suitable to make such lenses/mirrors, depending on your required accuracy.

Good luck in your search.

Note that you should check that the material will reflect well at the wavelength you will be using.

I once tried to use some tape which was highly reflective to visible light with an infrared sensor/emitter, and found that it was a very poor reflector at IR wavelengths.

Also, you'll only get a "degree of perfection" - as far as I know, no-one has yet come up with a perfect reflector.

Hi JohnDG, I can turn on or change channels on my TV by aiming my infra-red (TV control) emitter towards my front room window, I have also done the same by pointing it towards a small bronze statue and a porcelain vase on a shelf opposite from the TV.

Xanasax

Yep - mine works if I point it at the wall behind my head. IR reflects from many (if not all) surfaces; some better than others.

You can get a variety of mirrors from sources such as Edmund Optics. Edmund has broadband mirrors and laser-line mirrors. A flat mirror would need careful alignment to reflect the beam right back to you. Here's a link to Edmund Optics:

http://www.edmundoptics.com/

You might want to consider a single corner-cube reflector or a corner-cube reflector array. The advantage of a corner-cube reflector is that it will retro-reflect the beam (exactly back toward the source) even with very crude alignment. Here's a link to some corner-cube arrays:

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productid=2088

Folks, let me keep it simple, a FIRST SURFACE mirror is the general type of mirror. Its reflective surface is at the top of the glass, not on the back side, through which the light would have to pass and reflect. Some of the mirrors are made of metal. As suggested above, Edmonds is a great place to shop. Best to you and your venture.

Three first surface mirrors can be used in what they call a corner reflector to send the beam exactly back parallel to the incoming beam.

A single mirror can not be used for this.

Corner Reflector

Google will give you more

Glass beads are very broad and although they are retroreflectors, they are not perfect, for use on the roads you do not want perfect retroreflectors, you want a degree of directionality to enhance what the driver sees from his headlights. If the road signs were covered with perfect retroreflectors, the driver would be outside the cone of reflection.

Surveyors want perfect one as they use them in broad daylight and they need the signal to noise ratio they provide

Having been involved in the design and manufacture of multiple reflectors for automotive applications your comment deserves response.

The reflectors used for vehicles and roadside signs are (by design) divergent to give a 1.25 degree cone angle so that a driver can see the reflected light from his/her own vehicle lights. It is not a matter that they could not provide the S/N conditions required for survey, but are designed for the purpose they satisfy.

We designed and build refelctors to satisfy CMVSS (Canada), FMVSS (USA), ADR (Australia) and ECE (Europe) automotive use. For these applications, the S/N is defined at various divergence angles in preference to "beam path".

Manufactured reflectors still have the potential to provide poor response as an outcome of material processing issues (like material shrinkage) and such.

Yes, I was aware that vehicle reflectors have engineered divergence. No point having a perfectly parallel retroreflector.

A single first surface mirror (gold, silver, aluminum) can be used to reflect the beam if you have several hundred dollars worth of positioning equipment with suitable adjustments, and a rigid surface to mount all the components (laser and reflector). A corner reflector is much simpler to work with, since in terms of alignment close counts. They cost roughly 2X as much as a high quality first surface mirror with the same area. Edmund is an excellent source for either.

Surveyors use a prismatic device for longer range. The retroreflectors based on glass beads will work at short ranges, but their divergence is excessive for longer ranges in daylight.

http://www.google.ca/search?hl=en&source=hp&biw=1440&bih=755&q=survey+%2Bretroreflector&btnG=Google+Search&aq=f&aqi=&aql=&oq=

http://www.google.co.in/imgres?imgurl=http://upload.vipulg.com/Physics/473/Chapter%25208_files/Chapter%25208-3.png&imgrefurl=http://www.tutornext.com/help/total-internal-reflection-prism&h=363&w=885&sz=6&tbnid=THFUYxFxD3YHFM:&tbnh=60&tbnw=146&prev=/images%3Fq%3Dtotal%2Binternal%2Breflection%2Bprism&zoom=1&q=total+internal+reflection+prism&usg=__46MFZcWJD5qD4gcwUTgjvr2yxSw=&sa=X&ei=l8lOTfrYFpDwrQfQ_5HaBg&ved=0CFYQ9QEwCA

You can also try Thorlabs http://thorlabs.com/navigation.cfm?Guide_ID=15