Dual-Purpose Pixels: The Fusion of Emission and Analysis

Researchers at ETH Zurich have pioneered a breakthrough in materials science: pixels capable of both generating and interpreting light. This innovation suggests a future where the boundary between a camera and a screen disappears, resulting in integrated two-way camera-displays.

Published on 24.06.2026 by Oliver Morsch

📜 A Brief History of the Pixel

The term ~~"picture element"~~—eventually shortened to pixel—first appeared in the American publication Wireless World back in 1927. For nearly a century, pixels have been specialized tools:

Displays: Control light to create an image.
Sensors: Analyze light to capture an image.

Until now, a pixel could only perform one of these roles. However, a team led by Professor David Norris at the Optical Materials Engineering Laboratory has shattered this dichotomy.

🛠️ The Technology: Fourier Pixels

The team's work, published in the journal Nature, leverages the physics of light wave interference. When light hits a surface, waves from various points overlap. Depending on the surface's geometry, these waves either reinforce each other or cancel out.

The Process Flow

The researchers use nanometer-precise sculpting to manipulate light via surface plasmon polaritons (surface waves).

To determine the exact surface architecture required for a specific image, the team employs Fourier analysis. This mathematical approach allows them to calculate the necessary patterns to steer light precisely.

📊 Comparison: Traditional vs. Fourier Pixels

Feature	Traditional Pixel	Fourier Pixel
Function	$\text{Emit}$ $\mathbf{OR}$ $\text{Analyze}$	$\text{Emit}$ $\mathbf{AND}$ $\text{Analyze}$
Control	Intensity (Bright/Dark)	Intensity, Phase, & Polarisation
Mechanism	Simple Filtering/Emission	Surface Wave Interference
Complexity	Low	High (Nanometer Precision)

🌈 Controlling Phase and Polarisation

These pixels do more than just toggle brightness. They can manipulate the polarisation (the oscillation direction of the electric field) and the oscillation phase.

"In addition to light intensity, meaning the bright and dark areas from which images are created, our Fourier pixels can also control other properties of the light waves, for example their polarisation," explains doctoral student Yannik Glauser.

Key Capabilities:

Arbitrary Polarisation: Achieved by overlapping surface waves of different polarisations.
Phase Manipulation: Ability to create unique shapes, such as doughnut-shaped light beams (beams with a central hole).
Chromatic Versatility: Works across various wavelengths to produce full-color imagery.

🔍 The Analysis Mode

The "bidirectional" nature means the process can be reversed. To analyze light, the pixel acts as a sensor. As postdoctoral researcher Sander Vonk notes:

“We can also, however, apply the principle of interference and Fourier analysis in the opposite direction to analyse light using the Fourier pixel.”

By superimposing an incoming light wave with a known reference wave, the pixel creates an interference pattern. The phase $\phi$ and polarisation can then be calculated using the formula: $\text{Result} = \mathcal{F}^{-1}(\text{Interference Pattern})$

🚀 Future Implications

Because Fourier analysis is mathematically streamlined and doesn't require cumbersome modeling, these pixels are highly versatile.

Potential Applications:

Hybrid Hardware: Devices that are simultaneously high-res screens and high-res cameras.
Telecommunications: Enhancements in fibre-optic internet cables.
On-Chip Computing: Since surface waves can perform calculations directly within the material, the pixels could potentially process data and react to images without needing an external CPU.

(Image: Representation of light waves scattering and interfering to create patterns)

# Conceptual logic of a Fourier Pixel
def fourier_pixel(input_light):
    if mode == "EMIT":
        return sculpt_surface(fourier_transform(target_image))
    elif mode == "ANALYZE":
        return calculate_phase(interference_pattern(input_light))