Here's a very brief and detailed view of the laser output on a fluorescent target. The power source is a cheap HV module, exactly like the HV module that was featured in the presentation. My apologies for the annoying sound - the spark gap is quite loud. Use hearing protection when operating these lasers!
Here's a very brief teardown and reassembly of the laser. It provides a little more visual detail than was possible in the formal presentation.
The high voltage module can be purchased on eBay for a few dollars. It is falsely advertised as being a "3.6v-6v to 400kV 400000V Boost Step-up Power Module High Voltage Generator", but anyone with high voltage experience can recognize the obvious exaggeration of this claim. For my demonstration I connected the input to the 3.3V DC output from an ATX power supply and measured around 2.7V DC across the input to the module at a current of 2.4 Amps. With 50 Ohms resistors across both sides of the module output, a small xenon camera flash did not become hot as it did during previous test (with no resistors at the output, and an input of 4.5V at 3.3 Amps.
Although the theoretical limit of the channel is 9 1/2 inches based upon an 800 picosecond pulse (only a 4-3/4 inch long channel, if a rear mirror is included in the design), this limitation is possibly more applicable to a design that is optimized for maximum efficiency. I've obtained good results with longer channels, even using thicker dielectrics such as plastic signs (see image below). With the longer channel, tapering is easier (for greater output at the wider end) because the difference in separation is more resolvable, for a given angle, than it is for a shorter channel.
Professor Mark Csele's Homebuilt lasers, with comprehensive and practical information on the construction of TEA nitrogen lasers and more. http://technology.niagarac.on.ca/people/mcsele/lasers/LasersTEA.htm Sam Goldwasser's inexhaustible library of scratch made lasers devices, including the stories and experiences of those who built them, featuring the nitrogen laser https://www.repairfaq.org/sam/lasercn2.htm#cn2toc The combination of capacitance, frequency and current can enable charging and discharging between AC peaks, thereby permitting small TEA lasers to run directly off of the unrectified output from a basic iron-core neon sign transformer https://youtu.be/hcD85lj3qmI A simple, straightforward tutorial, showing how to build a TEA laser https://youtu.be/v9sKqGC3t-0
