My Projects: Organic Dyes Pumped by Nitrogen Lasers

First Successful Results

Here is a photo of Rhodamine 6G in 91% isopropyl alcohol, in a homemade cuvette, pumped by a homemade TEA nitrogen laser. It marks the first time I have been able to use one of my nitrogen lasers to lase an organic dye —

The cuvette is made of four microscope coverslips, epoxied together and epoxied onto a microscope slide.

It is extremely important to have the correct concentration of dye in the solution, and it really helps to have a cylindrical lens to focus the beam from the nitrogen laser into a line on the front face of the cuvette. If you do not have a cylindrical lens, you will need either external mirrors or an extremely powerful nitrogen laser.

Here is 4-Methyl-Umbelliferone, also in 91% isopropyl alcohol, but with a few drops of ammonia added (4-MU requires an alkaline environment) —

Here is Rhodamine 6G being lased by one of my TEA nitrogen lasers, but with air in the channel rather than nitrogen. You can see that the spot on the target is not very bright. That’s because this is hard to do!

One important thing that is not visible in the photo above is the fact that this is not an LC-Inversion circuit laser. It is a Charge-Transfer circuit. Here is an overview:

(The CD disk is for scale, so you can see how large the parts of the laser are.)

Notice that the positions of the spark gap and the laser channel are swapped in this design, and that the main storage capacitor is considerably larger than the “peaker” capacitor. (The peaker is just the right side of the laser; the rod on the left is connected to the ground plane.)

Nitrogen vs Air

Here are some photos showing the difference in output. Each picture shows four or five pulses from the TEA nitrogen laser hitting a cuvette of 4-Methyl-Umbelliferone. The output of the dye is shown on paper and on cork. The upper two photos were taken with air in the laser, and the lower two are with nitrogen. As you can see, nitrogen works a lot better!



Contact Information

You can reach me at an email address that you construct from the following three gmail pieces: com, along with jarrod694. (I don’t offhand know whether that’s enough to prevent robots from harvesting the@address.and making spam from it, but I certainly hope so.)

Last modified: Sun Mar 25 01:11:08 EDT 2007