Until now, our Helder 2 performance page has included Calculated irradiance values based on lens angle, distance, and our design targets for optical output. Today we can finally share Measured light output from lab testing — and it’s great news.
We tested Helder 2’s two light channels separately (NIR and Red) using a spectroradiometer system in controlled indoor conditions (22°C, 50% humidity). These reports confirm both the optical power (radiant flux) and the actual wavelength centers of the LEDs.
What we tested
Helder 2 uses two distinct channels:
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Near-Infrared (NIR) — invisible light centered in the ~850 nm range
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Red — visible deep red centered in the ~630 nm range
For each channel, the lab report includes:
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Radiant Flux (optical power output) in mW
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Peak wavelength (where the emission is strongest)
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Center / Centroid wavelength (useful for characterizing the overall spectrum)
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HalfWidth (approximate spectral bandwidth)
Key results (Measured)
1) NIR channel (Measured)
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Measured NIR radiant flux: 9210.632 mW → 9.21 W optical
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Peak wavelength: 855.9 nm
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Center wavelength: 851.3 nm
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Centroid wavelength: 847.1 nm
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HalfWidth (bandwidth): 33.4 nm
What this means: The NIR output is strong, and the spectrum is exactly where we want it — centered in the high-800 nm neighborhood with a normal LED bandwidth.
2) Red channel (Measured)
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Measured Red radiant flux: 1223.215 mW → 1.223 W optical
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Peak wavelength: 631.2 nm
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Center wavelength: 629.7 nm
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Centroid wavelength: 628.4 nm
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HalfWidth (bandwidth): 17.8 nm
What this means: This is a clean, narrow, deep red centered around ~630 nm. That’s the precise “true red” band many people expect when they say “red light therapy.” (Earlier draft copy sometimes says ~650 nm; this measurement lets us publish the real number with confidence.)
What this means for mW/cm² at our recommended distance (20 cm)
On our product page we describe a typical use setup:
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Lens: 30° (full angle)
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Distance to skin: 20 cm
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Using a simple cone model, that produces a calculated spot area of ~90.2 cm² at 20 cm.
Now that we have Measured optical power, we can compute average irradiance by dividing measured optical power by the calculated spot area:
Irradiance at 20 cm (Calculated from Measured optical power)
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NIR irradiance: 9210.632 mW ÷ 90.2 cm² = ~102.1 mW/cm²
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Red irradiance: 1223.215 mW ÷ 90.2 cm² = ~13.6 mW/cm²
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Total (Red + NIR): ~115.7 mW/cm²
✅ Bottom line: Our goal was “roughly ~110 mW/cm² at 20 cm,” and this first measurement round lands essentially right on target.
Important note: This is an average irradiance estimate based on beam geometry. In real life, LED optics often produce a brighter center and softer edges — which is why the next step is a true measured irradiance map (a grid/heatmap).
Why we’re excited: the “Calculated vs Measured” story is working exactly as intended
We’ve been building Helder 2 with an “open spec” mindset:
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When something is based on design targets and geometry, we label it Calculated.
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When we validate something in the lab, we label it Measured.
Today’s update is a big milestone because optical output power and wavelength are two of the most important foundations for honest performance reporting — and now we can publish them as Measured.
What we’re updating on the product page right now
We’re updating our performance section to include Measured values such as:
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NIR optical power: 9.21 W (Measured)
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Red optical power: 1.223 W (Measured)
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NIR peak wavelength: 855.9 nm (Measured)
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Red peak wavelength: 631.2 nm (Measured)
And we’ll keep the irradiance lines clearly labeled like this:
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mW/cm² @ 20 cm: Calculated from Measured optical power + lens geometry
That’s an important distinction — and it’s how you keep a spec sheet honest and technically clean.
What’s next: the measurement everyone wants (irradiance map + uniformity)
Measuring optical power in a sphere is the right “first truth.” The next truth is what customers feel and understand visually:
Next measurement round (planned)
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Measured irradiance (mW/cm²) at 10 / 20 / 30 cm
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Beam profile / uniformity (center vs edge)
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Red vs NIR split at each distance
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Optional: Face/Head Mode reduction measured relative to Body Mode
Once that’s complete, we’ll replace the remaining geometry-only lines with true Measured irradiance values.
Final takeaway
This first test round confirms that Helder 2’s light engine is already delivering where it matters:
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Strong NIR output: 9.21 W optical (Measured)
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Solid deep red output: 1.223 W optical (Measured)
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Wavelengths verified: ~856 nm NIR peak and ~631 nm red peak (Measured)
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At 20 cm with 30° optics: about ~116 mW/cm² total average irradiance (Calculated from Measured optical power)
If you care about performance specs and you’re tired of vague marketing numbers, this is exactly the kind of transparency we plan to keep publishing as Helder 2 moves from prototype into production