Take a sapphire cut like a diamond. THIS WILL NOT WORK WITH AN ACTUAL DIAMOND. It must be clear or as transparent as possible. Much like what is being sold as diamonds.
Look for an irradiated, synthetic sapphire with no flaws or occlusions. The sapphires being used must be as close to a perfect cone as possible. By that, I mean the diameter of the circle must be equal to the depth of the point from the center of the top of the gem (which also includes the crown and girdle). Start out with a ¼ caret sapphire, but, for different frequencies and applications, larger and smaller sapphires can be used.
Use low powered lasers to modulate broadband data on the crown of the sapphire. More than one laser or different colors can be used simultaneously. Ok. Here’s the trick; you must first irradiate the sapphire with ultrasound, at the correct frequency for the size and cut of the gemstone. When the correct frequency is found, the sapphire will be harmonized to act as a terahertz transmitter. I can help you with determining the ultra-sound frequencies.
This can be done with sapphires bought at a jewelry store, but will be better when the point is smoothed into a cone with no edges. This is important because with a smooth surface on the point, you can use a matching cone made from an alloy of platinum (at least 90%) that is 3mm thick with a 1mm hole. This platinum cone can be used to adjust the signal-to-noise ratio by moving it closer to, or further away from the transmitter gem.
This approach is small, lightweight and can be mass-produced. This will produce transmitters from 300 GHz to 3 THz and can be applied to transmitters at 30 to 300 GHz as well.
For those of you who know anything about the history of transmitters, this is a kind of return to the crystal transmitters used in radios during the 1920s and 30s, but this one is on steroids.