Laser power measurement

Laser Power Measurement

Operates under the rules in ../../INSTRUCTIONS.md (reference-first, reference-only, interactive mode).

When to use this skill

When an operator or engineer needs to make a laser-power measurement — for incoming inspection, after a laser swap, as part of routine maintenance, or to validate a recipe. This skill walks the 7-step procedure from measuring-laser-power.md with a pause for confirmation at each step.

References to load at start

• references/measuring-laser-power.md — primary
• references/laser_process_calculations.md — for any spot-size or fluence sanity checks during configuration

Inputs to gather BEFORE Step 1

Ask the operator, one at a time or in a single block:

1. Laser model and nominal output power (e.g., "an industrial 200W ns fiber laser, set to 100W").
2. Wavelength (1064 nm? 532 nm? UV?). Required for the wavelength correction step.
3. Detector model in use, and whether anticipation is enabled.
4. Where in the beam path the measurement is being made (after focus lens? Before scanner? At laser output?).
5. PPE in place — laser-safety glasses for the wavelength, beam tube, beam stop.

⚠️ Do not proceed past this point until PPE confirmation is received. ⚠️ The eye's blink reflex provides no protection at IR wavelengths — confirm explicitly.

→ Pause: confirm all inputs received, then proceed to Step 1.

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Workflow — 7 gated steps

Per measuring-laser-power.md. Run in order. Pause after each step. Confirm completion (or surface anomaly) before moving on.

Step 1 — Warm-up

Per measuring-laser-power.md Step 1.

Ask the operator to fire the laser and let it stabilize:

• 5 minutes for ns and CW fiber lasers
• 10–20 minutes for ps lasers

Reason: optical components shift while the laser reaches thermal equilibrium with its environment.

→ Pause: "Has the laser been on for the warm-up time? Ready to proceed?"

Step 2 — Verify detector specs match laser

Per measuring-laser-power.md Step 2.

Walk through each spec check:

• Average power within detector range?
• Power density within range?
• Pulse energy within range (for pulsed lasers)?
• Energy density within range?
• PRF within range?

→ Pause: confirm each is in spec. Stop the procedure if any are out of spec — request a different detector before going on.

Step 3 — Beam size on detector

Per measuring-laser-power.md Step 3.

Target: 40%–60% of the optical aperture.

Ask the operator:

• What is the detector aperture diameter?
• What is the current beam diameter at the detector position?

If not in 40–60% range:

• Without F-θ in path: enlarge the beam.
• With F-θ in path: maximize as space allows, or use a diffuser.

⚠️ A focused beam (after F-θ) on the detector creates very high power density — risk of damaging the detector. Limit exposure time.

→ Pause: confirm beam size, or report inability to reach target.

Step 4 — Heat up detector (laser ON, 2 min)

Per measuring-laser-power.md Step 4.

The detector head is constantly exchanging heat with its surroundings. Heating it up first eliminates that offset from the measurement.

→ Pause: confirm 2 minutes elapsed. Confirm operator is ready to block beam for Step 5.

Step 5 — Block beam (laser OFF or blocked, 2 min)

Per measuring-laser-power.md Step 5.

Block the beam, allow head to reach thermal equilibrium. For heads ≤ 30 W rated, 1 minute is sufficient.

→ Pause: confirm 2 minutes elapsed.

Step 6 — Zero

Per measuring-laser-power.md Step 6.

Operator zeros the monitor. Laser must be off and environment thermally stable.

→ Pause: confirm zero captured. Read the displayed zero value back to the operator and log it.

Step 7 — Take the reading (laser ON, 1 min)

Per measuring-laser-power.md Step 7.

• If anticipation is enabled: reading available in ≤ 1 second.
• If anticipation is disabled: wait 1 minute for stabilization.

Record:

• Average power reading.
• Time when reading was taken.
• Wavelength correction factor applied (Y/N — see post-checks below).

→ Pause: confirm reading captured.

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Post-measurement checks

Per measuring-laser-power.md — Additional Notes.

Wavelength correction

If the laser wavelength is not 1064 nm, confirm:

• The per-detector correction factor was applied (auto-applied if the monitor knows the operating wavelength).
• The correction value used.

If the operator is uncertain, the reading is not valid until this is sorted.

Zero check

Did room temperature drift during warm-up? If yes, re-zero before trusting the reading.

Repeatability

Compare to the previous reading on the same laser/detector pair:

• Power-meter repeatability: ±0.5%.
• Differences larger than 0.5% are real and worth investigating:
  • Laser drift / warm-up not complete?
  • Optic contamination on the path?
  • Alignment shift?

→ Pause: ask the operator to log the reading and any notes. Skill complete.

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Output

A measurement record (markdown):

• Date / time
• Laser ID, detector ID, configuration
• All 7 step confirmations
• Final reading + wavelength correction status
• Any anomalies flagged
• Comparison to last known reading if available

Save to outputs/laser-power-measurement/<YYYY-MM-DD>-<laser-id>.md.

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Cross-skill links

• If the reading is unexpectedly low: hand to laser-troubleshoot (Steps 2–4 there cover optic contamination and alignment).
• If repeated readings differ by more than 0.5% with no obvious cause: also laser-troubleshoot.