This could be the exemplar prototype for Dune knives that can penetrate a Holtzman Shield. Also recall in Dune there is an aversion to technology, so the simplicity and required human operation is a perfect fit.

> in Dune there is an aversion to technology

Just computers, no? IIRC they use knives because the shields stop fast-moving objects like bullets, so you need a slow-moving object like a knife.

Dune's vibrating shield and corresponding weapons.

Raven in Snowcrash? Not quite ultrasonic iirc but extremely thin, like the wire developed in three body problem

It's seemingly quasi-semi-related to The Foundation's 'atomic knives'?

dune?

evanghelion