In development · pilot open
THz-TDS for composites.
Terahertz time-domain spectroscopy turns picosecond light pulses into layer-by-layer thickness and subsurface defect maps, without contact, couplant, or ionizing radiation. It is the first modality on the Sondera pipeline, and the pilot is open.
The modality
Light pulses that see inside composites.
A THz-TDS system fires a broadband terahertz pulse, about a picosecond long, at the surface of a part. Terahertz radiation passes through most non-conductive materials, so the pulse travels into the composite and reflects a little energy back at every interface it crosses: the front surface, each coating or ply boundary, a delamination, the back wall.
The instrument records those returning echoes as a time-domain waveform. Because the speed of the pulse inside each material is known, the arrival time of every echo maps directly to a depth. That is the raw signal Sondera turns into thickness numbers and defect maps.
What it measures
Four things one waveform can tell you.
Coating and layer thickness
Per-layer thickness of paints, primers, and multi-layer coatings from a single non-contact measurement, down to tens of micrometers.
Delaminations and disbonds
Air gaps and weak bonds appear as extra echoes and phase changes between plies or across an adhesive bondline.
Subsurface defect mapping
Raster a surface and each waveform becomes a pixel, building depth-resolved, C-scan style maps of where indications sit and how deep.
Density and cure variation
Changes in porosity, density, and resin cure shift how the pulse slows and attenuates, giving a window on material state, not just geometry.
How it works
From a picosecond pulse to a signed-off report.
Emit a picosecond pulse
A broadband terahertz pulse is directed at the part from one side. No couplant, no contact, no radiation hazard.
Capture the echo train
The reflected time-domain waveform carries an echo from every interface the pulse crossed, from the front surface to the back wall.
AI signal processing
Denoising and deconvolution separate overlapping echoes and recover a clean impulse response, even for thin or closely spaced layers.
Detect and quantify
Models turn echo timing into per-layer thickness and locate defects by depth, with a confidence measure attached to every call.
Map to a decision
Results are compared against acceptance criteria and assembled into a traceable, audit-ready report.
Why THz-TDS
Where other methods struggle.
Ultrasound needs a couplant and good contact. X-ray means ionizing radiation and two-sided access. Terahertz sidesteps both for the materials it suits best.
- Non-contact and couplant-free: nothing touches the part
- Single-sided: measure from the side you can reach
- Sees non-conductive materials: composites, coatings, foams, ceramics, radomes
- Non-ionizing: safe on the shop floor, no radiation controls
- Quantitative and per-layer: real thickness numbers, not just pass or fail
Where it fits
Built for composites and coatings.
Not sure whether your material or defect is a fit? That is exactly what the pilot is for. Describe the part and we will tell you plainly what THz can and cannot resolve.
Built on research
Physics first, then the model.
The THz module grows out of peer-reviewed terahertz NDE research and physics-based electromagnetic modeling. FDTD and finite-element simulations generate training and validation data across material stacks and defect types, so the models are grounded in the wave physics of the measurement rather than fit blindly to data. Every detection carries a confidence estimate, and nothing is a black box where a measurement standard applies.
The THz pilot program is open.
We are working with a small group of partners on real composite and coating inspection problems while the module is built. Pilot partners send us scans or a measurement problem, get analysis back from the team, and help shape the roadmap. Composite materials and THz data get first priority.