Well, it looks like you have everything you need except for a reliable 12 V DC power supply! Have you tried substituting an ordinary lead-acid automobile battery for the transformer and Asian converter, just to see if it all works okay?
I assume the object mounted on the finned circular heat sink with the fan behind it is the laser diode. If so, then I am quite surprised that it allegedly draws a measly 165 mA if such a large heat sink is required to safely operate the laser diode. Perhaps the diode is rapidly pulsed by the Arduino, and the 165 mA is the average current drawn instead of the steady-state? High peak-current pulses are the only thing I can think of that would lead to the quick demise of the Asian converter. These are sold by the thousands (if not millions) world-wide for mundane tasks like powering up laptop computers, but they may not be suitable for your application. Try the car battery, then get back here with the results.
Laser fences are problematical in terms of effectiveness. It is very difficult to deliver enough beam power to do any real damage during the short interval the "fence" is breached. I once accidentally burned myself by reaching across an optical bench to turn on a little 5 watt Sylvania CO2 laser:
This was a highly collimated 10.6 μm continuous infrared beam (invisible), and my arm was a few feet from the exit aperture when I turned it on. My immediate reaction was to withdraw my arm from the beam, suffering only a minor burn. A larger animal, such as a horse or a cow, might flinch and jump out of the beam, but it is doubtful that would be an effective deterrent to passage through the "fence" since there is no obvious "cause and effect," such as is provided by the wire of an electric fence. Likely as not, an animal (or a human) would just run through the beam since there is no physical obstruction, nor enough power continuously on-target to cause more than minor discomfort..
About this same period of time (late 1970s) I visited a lab at Wright-Patterson AFB (WPAFB) here in Dayton OH where they had rigged up a kilowatt or so CO2 laser to provide materials testing of aircraft structures for susceptibility to laser damage from a laser weapon system. Of course no such weapon systems existed then, but it is always a good idea to be prepared. One of our engineers managed to lean over the beam, dangling his tie directly into the beam. The end of the tie instantly vaporized, leaving him with an impressive souvenir of his visit. A "laser fence" built using
that laser would definitely have posed a serious threat of bodily harm. The beam was about six inches diameter IIRC.
At that time we were working with the Air Force Weapons Laboratory at Kirtland AFB, Albuquerque NM to develop and test high-energy laser (HEL) weapon systems for installation and flight-test on the Airborne Laser Laboratory aircraft, now mothballed at the Museum of the U.S. Air Force at WPAFB. Later, some wag labeled us Star Warriors, supposedly after the George Lucas film of similar name, but we just thought it was a lot of fun playing around with these new laser toys, and maybe someday helping to defend the country from missile attack, if it had all worked out as envisioned in the 1970s. Except it didn't. And there are no current plans to continue along that line of development.
I have visited very secure government facilities that use "laser fences," not as deterrents to entry but simply as invisible sensors that warn when and where a perimeter is breached. An armed response team with real guns and real bullets then rapidly follows. Also, these facilities employ multiple sensor systems, including a form of radar, that are not easily defeated with "smoke and mirrors" or similar James Bond trickery. So, good luck making an effective laser fence with low-power laser diodes.
BTW, my secret dream is to build a fly-zapper that would incinerate flies by tracking them in-flight using gimbaled galvanometer-driven mirrors and a five or ten watt diode laser. Just being able to target and track a fly would be a hoot, but the ability to then deliver a lethal blast of light (any wavelength!) would be icing on the cake and a mark of true achievment. After that I could truly call myself LaserMan! Da da dada dada dada... LaserMan!
I am not interested in selling my NSTs, preferring to pass them on to my children and grandchildren, at least one of whom is already an electrical engineer. If you get a chance to visit Las Vegas, there are probably hundreds of NSTs available from the demolition of old casinos. Surely, someone there
must be collecting and selling all those NSTs!