Source: https://guthlabs.ai/docs/instruments/double-slit-single-slit-diffraction-calculator/implementation/

instrument implementation / implementation-contract

# Double-Slit / Single-Slit Diffraction Calculator implementation

A source-bound implementation contract for Double-Slit / Single-Slit Diffraction Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t6-101

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification exposes several unhandled edge hazards: d=0 produces undefined division, orders with |mλ/d|>1 produce no real diffraction angle, and m=0 in the single-slit formula is the central maximum rather than a minimum. Signed-order reporting is also convention-dependent. The supplied specification does not provide enough parameters or an intensity formula to compute a quantitative intensity pattern.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "mode": "double_slit",
    "slit_separation_d": "0.50 mm",
    "wavelength_lambda": "600 nm",
    "screen_distance_L": "2.00 m",
    "sampled_screen_positions_y": [
      "-1.20 mm",
      "0 mm",
      "1.20 mm"
    ],
    "normalized_intensity_model": "cos²(π d y/(λ L))",
    "position_model": "y_m≈mλL/d"
  },
  "expected_outputs": {
    "fringe_spacing": "2.400 mm",
    "fringe_positions": {
      "m=-1": "-2.400 mm",
      "m=0": "0 mm",
      "m=1": "2.400 mm"
    },
    "sampled_normalized_intensity": {
      "y=-1.20 mm": "0",
      "y=0 mm": "1",
      "y=1.20 mm": "0"
    },
    "curve_features": {
      "bright_maxima": "y=m(2.400 mm), m integer",
      "dark_minima": "y=(m+1/2)(2.400 mm), m integer"
    }
  },
  "working": "Convert units: λ=600 nm=0.000000600 m; d=0.50 mm=0.000500 m; L=2.00 m. Fringe spacing: Δy=λL/d=(0.000000600×2.00)/0.000500=0.000001200/0.000500=0.002400 m=2.400 mm. Positions: y_m≈mΔy, so y_{-1}=-2.400 mm, y_0=0, y_1=2.400 mm. For y=-1.20 mm, πy/Δy=π(-1.20/2.40)=-π/2, so I/I0=cos²(-π/2)=0. For y=0, I/I0=cos²(0)=1. For y=1.20 mm, πy/Δy=π/2, so I/I0=cos²(π/2)=0. Bright maxima occur when πy/Δy=mπ, giving y=mΔy. Dark minima occur when πy/Δy=(m+1/2)π, giving y=(m+1/2)Δy."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/double-slit-single-slit-diffraction-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/double-slit-single-slit-diffraction-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/double-slit-single-slit-diffraction-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`