Measured performance
Reconciled optical output, irradiance, and dose data
This page presents electrical input, optical output, irradiance, and emitting area measurements. All values are measured under stated geometry so that electrical power, optical power, and delivered dose close under basic conservation-of-energy checks.
typical operating point
typical operating point
derived estimate
Thorlabs S121C
Wavelengths
Measured optical output
Reconciled electrical and optical data
All optical measurements were taken on production hardware under steady-state conditions after thermal stabilization. The table below shows both full-power output and the typical operating point used during sessions. The operating point is derated by approximately 15% per channel to maintain stable irradiance across a full session duration, compensating for LED thermal sag at higher drive levels.
Configuration and session logging are provided via NFC. Irradiance measurements were acquired with calibration fixtures ensuring repeatable near-contact geometry and time-aligned with logged operating states.
| Mode | Full power (mW/cm²) | Typical operating point (mW/cm²) | Emitting area (cm²) | Optical output at operating point (W) | Optical fraction |
|---|---|---|---|---|---|
| 660 nm red | ~44 | ~39.5 | 20 | 0.79 | ~23% |
| 805 nm NIR | ~34 | ~31.0 | 20 | 0.62 | ~18% |
| Combined ‡ | ~78 | ~58 | 20 | 1.16 | — |
‡ Combined mode irradiance is a derived estimate — the sum of independently measured channel operating points minus an estimated I²R loss factor through the shared power path. It is not directly measured, as the Thorlabs S121C cannot distinguish between wavelengths under simultaneous dual-channel operation. Individual channel figures are directly measured under single-channel operation.
Individual unit calibration
Per-unit calibration record
Each unit is individually calibrated prior to shipment using a Thorlabs PM100D with S121C photodiode sensor (NIST-traceable calibration), with the device seated in a calibration fixture that maintains repeatable near-contact measurement geometry. The record below is a sample from a trial unit, illustrating the format and data captured for each unit. Production units will each carry their own serial-numbered record.
Output stability
Irradiance vs time
The charts below show near-contact irradiance over a 10-minute session for the red (660 nm) and NIR (805 nm) channels, measured independently under single-channel operation. Both channels remain within the ±2% calibration uncertainty band throughout. Red and NIR exhibit different thermal profiles — red shows a characteristic dip and recovery as junction temperature stabilizes, while NIR rises gradually — reflecting the distinct thermal behavior of each LED type at their respective drive levels. Temperature compensation is applied independently to each channel.
Combined mode irradiance is not shown as a measured trace. The Thorlabs S121C cannot distinguish between wavelengths under simultaneous dual-channel operation; the combined figure in the table above is a derived estimate.
Figure 1a. Red channel (660 nm) irradiance vs time. Mean: 39.64 mW/cm². Entire trace within ±2% calibration uncertainty band. NIST-traceable measurement, near-contact geometry.
Figure 1b. NIR channel (805 nm) irradiance vs time. Mean: 30.99 mW/cm². Entire trace within ±2% calibration uncertainty band. NIST-traceable measurement, near-contact geometry.
Measurement methodology
Geometry and instrumentation
Optical power density was measured using a Thorlabs PM100D power meter with an S121C photodiode sensor (400–1100 nm, 500 mW range). The S121C carries NIST-traceable calibration, providing a direct traceability chain to national measurement standards.
- Sensor positioned normal to the emitting surface at near-contact distance, using calibration fixtures for repeatable geometry
- Aperture-averaged irradiance — measurements taken at multiple locations across the emitting window
- Red and NIR channels measured independently; wavelength set to 660 nm and 805 nm respectively
- Red channel derated approximately 10% from full power (39.5 mW/cm² operating point vs ~44 mW/cm² full power); NIR channel derated approximately 9% (31.0 mW/cm² vs ~34 mW/cm²)
- Combined mode irradiance is a derived estimate — individual channel operating points summed with an I²R loss correction applied; not directly measurable as the S121C cannot distinguish between wavelengths under simultaneous dual-channel operation
- All measurements taken after thermal stabilization
- Published typical operating point values reflect the irradiance delivered during a normal session, not peak output
Derived exposure times
Session duration to reach target dose
Exposure times derived directly from typical operating point irradiance values using: Exposure time (s) = Dose (J/cm²) ÷ Irradiance (W/cm²)
Values are illustrative and not usage recommendations. Individual protocols vary based on treatment area, target dose, and clinical context.
| Mode | Operating point (mW/cm²) | 10 J/cm² | 20 J/cm² |
|---|---|---|---|
| 660 nm red | 39.5 | ~253 s (~4.2 min) | ~506 s (~8.4 min) |
| 805 nm NIR | 31.0 | ~323 s (~5.4 min) | ~645 s (~10.8 min) |
| Combined ‡ | ~58 | ~172 s (~2.9 min) | ~345 s (~5.8 min) |
‡ Combined mode irradiance is a derived estimate, not directly measured. Times are calculated from that estimate at the near-contact operating geometry and carry additional uncertainty relative to the directly measured channel figures.
Thermal behavior
Internal temperature vs time
Internal temperature vs time data reflect expected thermal stabilization behavior during multi-minute operation in combined mode. Thermal management is passive — no active cooling is required, and no cooling interval is needed between sessions under typical use conditions.
Figure 2. Internal temperature vs time for combined mode operation. Data reflect steady-state thermal behavior under near-contact use conditions.
Electrical and electromagnetic
EMC and interference
The device contains no intentional RF transmitters during operation. Internal switching regulators and control electronics operate below audible frequencies and are confined within the enclosure. During informal testing, no functional interference was observed when operating the device in proximity to common consumer electronics, including mobile phones and wireless charging equipment.
No claims of regulatory compliance or electromagnetic certification are made.
Regulatory context and important notes
Rejuvulite is designed and presented as a consumer wellness device and is not marketed as a medical device. No claims are made regarding diagnosis, treatment, cure, or prevention of disease. Individual experience may vary depending on distance, duration, and usage pattern.
The measurements and observations documented on this page characterize device behavior under defined conditions and do not constitute certification, regulatory approval, or compliance testing. In developing the hardware, general principles from established safety and performance standards were considered as reference points only, including:
- Electrical and mechanical safety practices commonly applied to consumer electronics
- Photobiological safety concepts related to wavelength, exposure, and thermal behavior
- Electromagnetic compatibility considerations relevant to battery-powered electronic devices
Formal testing against regulatory standards (e.g., FDA medical device regulations, IEC medical standards, FCC emissions limits) has not been conducted unless explicitly stated. This contextual information is provided for transparency and does not imply regulatory classification or clearance.