A "black body" is a theoretical object that will absorb all energy that strikes it.
 This means that nothing is reflected... and that nothing is very, very important.
 If we have something coming in and nothing going out, what happens?  Well, the black body increases temperature.  And thus we have the basis of many scientific instruments.  Keep in mind that when we speak about a black body, we are talking about an idealized concept but when we go to actually build one, it will never be perfect.

One of the things we want our black body to do is to absorb all colors equally across the spectrum including low frequency light in the infrared region to high frequency light in the ultraviolet region.  In other words, we want our black object black.  We would also like it to be mass-less but we will settle for as light as possible.  There are other criteria but for now we have the critical ones listed.

 Black:  There are a number of products that are black and NASA working with industry has developed some fancy ones that are very difficult and expensive to obtain. To keep our project inexpensive, we can use flat-black spray paint.
 Some paint works better than others and we want to have as much carbon black in the paint as possible and as little binder as can be achieved.  I found a product that I believe works better than black spray paint and that is Wire Glue.  This product is water based and dries to a conductive film and the vendor states that the product is nano-sized carbon.  You can find the product online at eBay, Amazon, and other distributors.

NOTE: I have during prototyping also utilized black primer paint, black engine paint, and various other high-carbon black spray paints. The Wire Glue gave me the most consistent results for low-power lasers; obviously, power over 1W optical may require a review of the target object. Remember, after air drying, use a heat (oven, heat gun, hot air) to thoroughly cure the carbon product.

Massless:  I tried to just use thin films of the Wire Glue without any supporting material and while it worked great, it is very difficult to work with and tends to tear.  Worst, if you do not illuminate it uniformly with your high power pointer, you can burn a hole right through it and destroy anything behind the film.  I convinced my family practice doctor to give me a few microscope cover glass slips.  I'm always asking for non-infectious and non-regulated medical items and he did not ask any questions; so, I did not have to explain the LASER experiment!  I did manage to get the company and specifics for the slips - an amateur scientist must document all the details: Vendor = Select / Desc. = Microscope Cover Glass / Size = 22mm x 22mm / Thickness - #1 / Material = silica glass After mixing the jar of Wire Glue (I used an ultrasonic jewelry cleaner) I applied 3 drops from a toothpick.  The liquid is thick and starts to dry rapidly so with the glass slip on a perfectly level and clean surface, coat one side with the three drops covering the entire surface. The conductive film must dry at least 24 hours before use.

I utilized some snap-together 35mm slide holders for the target holder.  The slides fit very nicely in a diamond configuration with only a very small portion of 2 corners being in contact with the holder.  Ensuring minimum surface contact will allow the carbon coating + glass to quickly elevate and maintain a stable temperature when exposed to high energy light. Heat energy only moves through conduction, convection, and thermal radiation and for this project, we must minimize conduction and convection to maximize heating of the glass slip from the laser energy absorption.

Electronics: Many online stores will sell the MLX90614 (or equivalent.) One such store is: SparkFun and another is: Amazon and another is: Adafruit

I will leave it as an exercise for...