# ⚛  L1 Principle — SRS — Stimulated Raman Scattering microscopy

**ID:** `L1-139` · **Status:** ⊙ Testnet (genesis catalog)

> **🌐 Domain:** Spectroscopy — *Background-free coherent vibrational microscopy*
> **🎯 Problem class:** linear inverse coherent · **🧮 Solution space:** concentration map
> **📡 Carrier:** photon · **🌫 Noise:** shot poisson
> **⚖ Difficulty (δ):** 3 · **⛓ Block:** 41554227

---

## 🧠 1. Introduction

**SRS — Stimulated Raman Scattering microscopy** is a **linear inverse coherent** whose unknown lives in **concentration map** space, within the **Background-free coherent vibrational microscopy** sub-domain of **Spectroscopy**.

Measurements consist of photons collected by an optical detector via a **stimulated raman** sensing mechanism.

The forward operator applies, in order: L · beat · twocolor operator; S · nonlinear · chi3 operator; L · modulate · highfreq operator; detector accumulates flux over the exposure window.

Observations are corrupted by Poisson shot noise from quantum-limited detection. SRS is linear in concentration, unlike CARS (|chi|^2). No non-resonant background. Signal is shot-noise limited; SNR scales as sqrt(I_p * I_s * tau).

## ⚙ 2. Forward Model

Physical chain: **x** → L · beat · twocolor → S · nonlinear · chi3 → L · modulate · highfreq → Temporal integration → **y** (detector).

```
y = ∫_t dt `L.modulate.highfreq` `S.nonlinear.chi3` `L.beat.twocolor` x,    measurements ~ Poisson(αy)
```

**Measurement DAG:**

| Primitive | What it does |
|---|---|
| `L.beat.twocolor` | L · beat · twocolor operator |
| `S.nonlinear.chi3` | S · nonlinear · chi3 operator |
| `L.modulate.highfreq` | L · modulate · highfreq operator |
| `int.temporal` | Detector accumulates flux over the exposure window |

## 🔬 3. Physics Fingerprint

| Property | Value |
|---|---|
| Domain | Spectroscopy |
| Sub domain | Background-free coherent vibrational microscopy |
| Carrier | photon |
| Problem class | linear_inverse_coherent |
| Solution space | concentration_map |
| Noise model | shot_poisson |
| Integration axis | spectral_and_temporal |
| Difficulty delta | 3 |
| L dag | 3 |

## 📡 4. Measurement Model

SRS is linear in concentration, unlike CARS (|chi|^2). No non-resonant background. Signal is shot-noise limited; SNR scales as sqrt(I_p * I_s * tau).

| Metric | Value |
|---|---|
| Metric | concentration_NMSE |
| Secondary | SNR_dB |

## 📏 5. Operating Range (Ω)

**Center problem class:** `hyperspectral_srs` · **Forward operator:** `srs_linear_forward`

**Center point:**

| Parameter | Unit | Value |
|---|---|---|
| H | px | 256 |
| K | — | 4 |
| W | px | 256 |
| Tau us | µs | 10 |
| N omega | — | 200 |
| Lambda p nm | nm | 800 |
| Lambda s nm | nm | 1040 |

**Allowed bounds:**

| Parameter | Unit | Range |
|---|---|---|
| H | px | 64 – 2048 |
| K | — | 1 – 10 |
| W | px | 64 – 2048 |
| Tau us | µs | 1 – 1000 |
| N omega | — | 1 – 500 |
| Xpm artifact | — | 0.0 – 0.2 |
| Rin laser noise | — | 1e-08 – 1e-05 |
| Thermal lensing | — | 0.0 – 0.2 |
| Focal volume error | — | 0.0 – 0.2 |

## 🎯 6. Tolerance (ε)

**Center tolerance:** NMSE 1e-3

| Metric | Range |
|---|---|
| Nmse | 1e-05 – 0.1 |

## ⚖ 7. Hardness Function

Hardness scales as **`epsilon_fn`** on **concentration_NMSE**, with κ = `50` and δ = `3`.

## 💾 8. Reference Dataset

- **primary** · weight 1.0 · IPFS _(not pinned yet)_

## 9. On-chain Registration

- **Chain hash:** `0x8a781ba7311546a2d58078908ac53338a67e43e82e87615c5171d48a9824ae66`
- **Chain tx hash:** `0x660149f63170f620ed6260984ef3616e28e26f17a22c7c0d255d841d558295fd`
- **Chain block:** `41554227`

---

## File Mapping

This bundle consists of: `L1-139.md`, `L1-139.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L1-139.md` | Source of truth — edit this | Human or LLM |
| `L1-139.json` | Structured metadata for the registry | LLM regenerates from the sections above |

**Prompt for your LLM after editing this Markdown:**

> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.

_This Markdown was auto-synthesized from the catalog row for `L1-139`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._