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From Classical Radiation to Near-Field Heat Control
The 150-year scientific journey that makes this technology possible
The physics behind the Micro-Gap Thermal Diode has been building for 150 years.
Each discovery brought science one step closer — but no practical device has ever been built.
This project takes the next step.
1879
1948
1971
2010s
Today
Stefan–Boltzmann Law
Heat obeys classical radiation rules. Objects emit thermal energy based on temperature —
but direction can't be controlled.
Casimir Effect
Two surfaces placed nanometers apart experience a measurable attractive force — with no contact.
Polder–Van Hove
Below 10 µm, heat tunnels across gaps through evanescent electromagnetic waves.
Lab Confirmed
Near-field enhancement measured at 100× classical limits — but only under ideal conditions.
The Gap Remains
The physics is proven. The device is not.
Heat used to be simple.
CLASSICAL FOUNDATION
For over a century, thermal radiation followed one rule:
The Stefan–Boltzmann Law.
Heat flowed based on temperature - symmetrically, in both directions, with no way to steer it.
The classical model had no concept of directional heat flow.
NEAR-FIELD PREDICTION
Heat can tunnel across gaps.
Polder and Van Hove predicted in 1971 that below ~10 µm,
heat transfer scales as 1/d² — not constant.
If the two surfaces have different material properties, the coupling depends on
which side is hotter — creating directional asymmetry.
This is what makes a thermal diode physically possible.
Why the material pair matters
The Emissivity Contrast
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