Spectrum: Optical
by Beykus-Y
Spectrum: Optical adds mirrors, lenses and beam emitters that let players route focused light through a world and trigger redstone signals with it.
What it does
Engineering around light beams is the focus here. A powered redstone block gives off a concentrated white beam at intensity 15, and a beam receiver that a beam strikes on its front face sends out a redstone signal. Together they make wireless redstone transmission and laser tripwires possible. Beams can be redirected, split and focused, so players can build optical networks in three dimensions that interact with the world and automate setups.
Filters are part of the same system. Color also determines which physical effects occur along the beam path and where it hits. Spectrum is a prerequisite, so the mod is meant to be used alongside that content, and Fabric Loader 1.21.1, Fabric API and Fabric Language Kotlin must be installed as well.
The mod runs on Fabric only, on 1.21.1, and is released under the MIT License without being open source. Quilt Kotlin Libraries (QKL) is required as a dependency next to Fabric API. Only the 0.0.4 beta build for 1.21.1 is listed, published on 2026-07-15.
Key features
Beam emitter
A redstone-powered block emits a focused white beam at base intensity 15.
Beam receiver
A receiver registers a beam arriving at its front face and then emits a redstone signal.
Standard mirror
A mirror reflects light horizontally and can be rotated through 8 directions in 45-degree steps by right-clicking.
Double-sided and vertical mirrors
Some mirrors reflect beams on both sides or bounce them up and down, redirecting light in more directions.
Converging lens
A converging lens accepts beams entering from its left and right sides and merges them into a single, brighter beam that leaves through the front.
Stained glass filtering
Beams pass through vanilla stained glass, which changes their color and lowers their intensity by 1 per block.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 2
How it compares
Rearview Mirror Mod is open source under the MIT License, is client-side only and is published for 1.21.11 on Fabric. ItemBeam is a Fabric mod for 1.21.4 – 1.21.11 that runs client-side only, under the MIT License and not open source. Laseredstone is a Fabric mod for 1.21.8 – 26.1.2 that is open source under the MIT License and runs on client and server, which is the same environment as this mod.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Spectrum: Optical | Fabric | 1.21.1 | Client and server | 2026-07-15 |
| Rearview Mirror Mod | Fabric | 1.21.11 | Client-side only | 2026-06-25 |
| ItemBeam | Fabric | 1.21.4 – 1.21.11 | Client-side only | 2026-08-09 |
| Laseredstone | Fabric | 1.21.8 – 26.1.2 | Client and server | 2026-06-16 |
Questions
Does Spectrum: Optical need Spectrum installed?
Does the server need Spectrum: Optical?
Which Fabric dependencies are required?
In the catalog
Spectrum: Optical is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 32,366 mods support Minecraft 1.21.1.
More from Beykus-Y
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What the author says
Spectrum is an engineering and optical mod for Minecraft (Fabric, 1.21.1) that introduces a system for generating, directing, focusing, and splitting beams of light. Build complex optical networks using mirrors, lenses, and filters in 3D space to interact with the world and automate your setups. Pass a beam through…
Official listing
- Modrinth page
- modrinth.com/mod/spectrum-optical
- Owner
- Beykus-Y
- Published
- 2026-06-23
- Updated on Modrinth
- 2026-07-15
- Facts verified
- 2026-10-15