On reread, I’m reminded of another topic of interest of mine: Laser entertainment lighting.
I was involved with, um, organized clandestine fiesta engagements in the 90s and the lasers we did have were rare, expensive, fragile!, hazmat (beryllium, asbestos), temperamental & exotic things pulled from surplus with thousands of hours already on the dial. It seems like mail ordering from a stapled ‘xeroxed’ paper catalog was as ancient as feather plumes but it wasn’t so long ago at all, lol. Argon & Helium-neon excited with high voltage, generating puny amount of desired light, sometimes lasing, for 1000x waste heat. Greens were diode pumped frequency doubling YAG, I remember buying a 5 milliwatt ‘pointer’ type for $300 in 1999ish.
Solid state blue & violet light emitting semiconductors were literally in the process of being invented at the time. I believe the Playstation 2 was the first widely available commercial device with a blue LED, the first most people might have seen. These breakthroughs allowed massive changes in many industries, efficient white LEDs, ever increasing data density, ever increasing display screen sizes & resolution, sensing & imaging tech. Blu-ray in 2005 was when the first blue lasers started to be seen, a couple milliwatts.
In the last two years, I’ve bought solid state, battery powered handheld laser devices that would have been considered science fiction at ANY price 30 years ago. Remember James Bond’s laser watch in Goldeneye? Yea right, gimme a break! Today: 200 Watt IR Laser Cannon, cheap!. I don’t have or want one of those those but the ones I do have will melt plastic, pop balloons, fry houseflies and beam bees, and blind a kid with the most beautiful 450nm blue beam. Or we could use the 530nm green one. Or the other blue one, I got a couple, they were only $40 EACH!?!
The advancement and availability of the tech to more easily generate the business-end of these tools, both for the ground penetrating radar and lasers, has made it really easy to underestimate the risk of misuse, malfunction, manufacturing errors, accidents. One can’t manufacturer a laser projector that is to be marketed and installed in public places without keeping a huge list of entities happy: FDA for the device approval, UL/CE, trade groups for communications compatibility (licensing), laser display variance for the installation specifics (usually requires mechanical interlocks & failsafe beam blocking), local codes for overhead lighting fixtures. And after all those people (and the customer) are signed off, the insurance rep could torpedo the whole thing with a glance. And first person to think they hurt themselves can ruin a poorly backed manufacturer. “Your laser maybe damaged my phone’s camera, I’ll see you in court!”
A 100-400 MHz radar sweep pointed up instead of down will potentially interfere with FM broadcast, military, civilian aircraft operations, space telemetry, police and fire dispatch. It can cause RF burns and invisible RF exposure hazards. Kids are going to use it on themselves and each other. People are going to try to use your radar to dig up real and imagined pipelines, UXO, unsolved mysteries, and treasure troves, and you might have to show that their mistakes aren’t your fault.
You CAN buy unlicensed laser projectors or radar radio transmitters and you DO incur all the risk and liability when providing (or allowing use, failing to secure, etc) those inherently dangerous things to unqualified people.