Anthony P
Well-known member
- Joined
- Oct 7, 2018
- Messages
- 533
- Points
- 63
Over the years, I have constructed several Lasers based on the Scientific American Amateur Scientist articles (Light And It's Uses). The original version of the N2 laser was word for word identical to the articles. This version 2.0 has several modifications which greatly improve performance.
In the photos, notice the most significant improvement in the use of the fire engine red paint (just kidding). First, the plexiglass plates were replaced with 2" PVC pipe. It was split by clamping it into a length of angle iron and running through table saw. This was done in 2 separate pieces due to the thickness of the saw blade. The capacitor plate was etched from FR4 board which is better than the G10 from SciAm. It has higher dielectric strength and greater heat resistance... not to mention that is much easier to find these days. Everything was assembled using JB weld. The silicon recommended by the article is a horrible choice for vacuum work. I have tested JB Weld vs Torr Seal in many a projects and the JB Weld performs as well, if not better in most cases. The power supply is a variac controlled Neon Sign transformer 3000V. When pk-pk voltage and a slight overdrive from the variac are factored in, output is 5000 VAC. This is fed into a simple 4 stage multiplier circuit for 20KVDC max. Performance is optimized when spark gap is set at 5.5-6.5mm. The final improvement is the use of actual polished quartz windows.
The cell is pretty straight forward. Pump light enters through a quartz window and laser exits through glass microscope cover slips. 1" width seemed to perform the best. No resonator is necessary, though an ordinary DCX lens at the output greatly enhances divergence.
2 special optics were used to focus the N2 beam onto the dye. The N2 beam has a bar shape which is familiar to any diode laser enthusiast. This passes through a quartz cylinder lens with a 50.8mm FL. At the back side of the N2 is a 2" dia, 20"FL concave UV enhanced Al mirror from Edmond Optic$. While not 100% necessary, it does significantly improve output.
The beam shots were difficult to photograph from a pulsed laser and I considered making a short video. Fortunately, I got lucky and was able to get some decent shots.
Finally, the dye is rhodamine 590 chloride often referred to as 6G. Concentration 1.5g/l. I have also used coumarin 450 for remarkable blue beams. The solvent was 200 proof reagent ethanol... cocktails anyone?
In the photos, notice the most significant improvement in the use of the fire engine red paint (just kidding). First, the plexiglass plates were replaced with 2" PVC pipe. It was split by clamping it into a length of angle iron and running through table saw. This was done in 2 separate pieces due to the thickness of the saw blade. The capacitor plate was etched from FR4 board which is better than the G10 from SciAm. It has higher dielectric strength and greater heat resistance... not to mention that is much easier to find these days. Everything was assembled using JB weld. The silicon recommended by the article is a horrible choice for vacuum work. I have tested JB Weld vs Torr Seal in many a projects and the JB Weld performs as well, if not better in most cases. The power supply is a variac controlled Neon Sign transformer 3000V. When pk-pk voltage and a slight overdrive from the variac are factored in, output is 5000 VAC. This is fed into a simple 4 stage multiplier circuit for 20KVDC max. Performance is optimized when spark gap is set at 5.5-6.5mm. The final improvement is the use of actual polished quartz windows.
The cell is pretty straight forward. Pump light enters through a quartz window and laser exits through glass microscope cover slips. 1" width seemed to perform the best. No resonator is necessary, though an ordinary DCX lens at the output greatly enhances divergence.
2 special optics were used to focus the N2 beam onto the dye. The N2 beam has a bar shape which is familiar to any diode laser enthusiast. This passes through a quartz cylinder lens with a 50.8mm FL. At the back side of the N2 is a 2" dia, 20"FL concave UV enhanced Al mirror from Edmond Optic$. While not 100% necessary, it does significantly improve output.
The beam shots were difficult to photograph from a pulsed laser and I considered making a short video. Fortunately, I got lucky and was able to get some decent shots.
Finally, the dye is rhodamine 590 chloride often referred to as 6G. Concentration 1.5g/l. I have also used coumarin 450 for remarkable blue beams. The solvent was 200 proof reagent ethanol... cocktails anyone?
