Optics

_{Focus Areas · Design document §3}

Available from: OP01 (Glassmaking) + MA01 (Geometry)

7 breakthroughs — CORE 5 · STANDARD 1 · RARE 1 — Ancient – Atomic

Builds on: Fire (2) · Social Organization (1) · Mathematics (1) · Philosophy and the Arts (1) · Chemistry (1) · Quintessic Physics (1) · Quantum Physics (1)

Leads into: Farming (1) · Seafaring (1) · Medicine (2) · Chemistry (2) · Electronics (2) · Nuclear Physics (1) · Quintessic Physics (1) · Quantum Physics (2) · Relativity & Cosmology (1) · Rocketry (1) · Materials Science (1) · Genetics (1) · Space Engineering (1) · Energy Systems (1)

_{The numbers count prerequisite links between this focus and the other. How to read the tables.}

Overview

ID	Breakthrough	Tier	Era	Prerequisites
OP01	Glassmaking	CORE	Ancient	F02 (Kiln Construction) + (F03 (Charcoal Production — potash from wood ash) or Desert/coast tile in territory)
OP02	Lens Grinding	CORE	Medieval	OP01 + MA01 (Geometry)
OP03	Telescope	CORE	Early Modern	OP02
OP07	Laser	CORE	Atomic	OP02 + (QP02 Quantum Mechanics, or QM-E03 Resonant-State Computing)
OP08	Spectroscopy	CORE	Modern	OP03 + CH06 (Periodic Table)
OP09	Ibn al-Haytham's Optics	RARE	Medieval	OP01 + PH01 (Formal Logic)
OP10	Semaphore	STANDARD	Early Modern	OP03 (Telescope) + SO04

Prerequisite map

flowchart LR
  n_OP01["OP01 Glassmaking"]:::CORE
  n_OP02["OP02 Lens Grinding"]:::CORE
  n_OP03["OP03 Telescope"]:::CORE
  n_OP08["OP08 Spectroscopy"]:::CORE
  n_OP10["OP10 Semaphore"]:::STANDARD
  n_OP07["OP07 Laser"]:::CORE
  n_OP09["OP09 Ibn al-Haytham's Optics"]:::RARE
  n_OP01 --> n_OP02
  n_OP02 --> n_OP03
  n_OP02 --> n_OP07
  n_OP03 --> n_OP08
  n_OP01 --> n_OP09
  n_OP03 --> n_OP10
  classDef CORE fill:#dbeafe,stroke:#1d4ed8,color:#0b1b3b
  classDef STANDARD fill:#f1f5f9,stroke:#64748b,color:#0f172a
  classDef UNCOMMON fill:#dcfce7,stroke:#15803d,color:#052e16
  classDef RARE fill:#fef3c7,stroke:#b45309,color:#3b2005
  classDef UNIQUE fill:#fae8ff,stroke:#a21caf,color:#3b0a3f

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_{Prerequisites within this focus. Box colour is the tier (blue CORE, grey STANDARD, green UNCOMMON, amber RARE, purple UNIQUE); dotted arrows are alternatives (“or”); a line can pass behind another box, so follow it from its start. 6 of these 7 breakthroughs also need breakthroughs from other foci, which the overview above lists.}

Breakthroughs

OP01 · Glassmaking

• Tier: CORE · Era: Ancient
• Prerequisites: F02 (Kiln Construction) + (F03 (Charcoal Production — potash from wood ash) or Desert/coast tile in territory)
• Unlocks: ⟨[+15]% Production when constructing [Lighthouse] buildings [in all cities]⟩ — glass for the lantern. Two traditions: soda glass, fluxed with natron or the ash of salt-loving plants from desert and shore (Egypt, Rome, Venice); and potash glass, fluxed with wood ash, the forest glass of inland Europe (Theophilus, c. 1120: two parts beechwood ash to one of sand washed from a river), later Bohemian crystal. The silica is everywhere: river sand, crushed quartz pebbles, sandstone (Civ V has no Sand resource).
• Notes: Inland China made glass with lead and barium (Warring States).
• Leads to: FA09 Greenhouse Cultivation, SF13 Submarine, OP02 Lens Grinding, OP09 Ibn al-Haytham's Optics, EN01 Vacuum Tube, SE01 Life Support Systems

OP02 · Lens Grinding

• Tier: CORE · Era: Medieval
• Prerequisites: OP01 + MA01 (Geometry)
• Unlocks: ⟨[+1 Science] from every [Scientist]⟩ — spectacles double a scholar's working life. ⟨[+1 Culture] from every [Artist]⟩ — the projected image, traced (Camera Obscura, merged here in v3.101: the same lenses, the same era).
• Leads to: OP03 Telescope, OP07 Laser, EN11 Radio

OP03 · Telescope

• Tier: CORE · Era: Early Modern
• Prerequisites: OP02
• Unlocks: Observatory; ⟨[+1] Sight <for [Water] units>⟩ (spotting). ⟨[-25]% enemy spy effectiveness [in all cities]⟩ (<when espionage is enabled> — forensics): the same lens-makers made both, Janssen around 1590 (Microscope, merged here in v3.105). Unlocks the Germ Theory path (MD05).
• Leads to: MD05 Germ Theory, MD20 Phage Therapy, CH14 Photochemistry, OP08 Spectroscopy, OP10 Semaphore, QP01 Wave-Particle Duality, GN02 DNA Structure

OP07 · Laser

• Tier: CORE · Era: Atomic
• Prerequisites: OP02 + (QP02 Quantum Mechanics, or QM-E03 Resonant-State Computing)
• Unlocks: Coherent light — a phenomenon, dual-framed by account. Atomic: stimulated emission (quantum). Elemental: a resonant cavity forces the aether / fire-phase into a single pure mode — a "Resonant Ray" (Substance) / "Harmonic Ray" (Process), drawing on QM-E03. Either way: ⟨[+10]% Strength <for [Ranged] units>⟩ (laser targeting).
• Notes: Light forced into a single voice — whether by quantum leap or by resonance.
• Leads to: QP07 Quantum Entanglement Mastery, RC03 Gravitational Waves Detection, RK11 Solar Sail, MS03 Metamaterials, ES11 Beamed Power

OP08 · Spectroscopy

• Tier: CORE · Era: Modern
• Prerequisites: OP03 + CH06 (Periodic Table)
• Unlocks: ⟨[+1 Gold] from [Mine] tiles [in all cities]⟩ — ore composition read without sampling. Prerequisite for Radioactivity (NP01) and Limiting Fineness (QM-E14).
• Leads to: CH28 Helium Extraction, NP01 Radioactivity, QM-E14 Limiting Fineness

OP09 · Ibn al-Haytham's Optics

• Tier: RARE · Era: Medieval
• Prerequisites: OP01 + PH01 (Formal Logic)
• Unlocks: Optics Academyⁿ [35/0; Scientist ×1]; +15% Insight to Optics; reveals the Scientific Method (PH04) as a concept.
• Notes: Islamic Golden Age. A purely intellectual breakthrough — reclassified as RARE rather than UNIQUE since it has no environmental basis.

OP10 · Semaphore

• Tier: STANDARD · Era: Early Modern
• Prerequisites: OP03 (Telescope) + SO04
• Unlocks: Semaphore Towerⁿ [improvement on Hill; 5 turns; ⟨[+2] Sight⟩; ⟨Gives a defensive bonus of [15]%⟩] — a message across a province in an afternoon.
• Notes: Relocated from the former Communications focus.