"Never measure anything but frequency." — Arthur L. Schawlow
Dual-comb spectroscopy measures the precise optical fingerprint of each molecule, allowing OSCAii to identify hundreds of species simultaneously in real time — from trace biomarkers at parts-per-billion to major gases at percent-level concentrations.
Every molecule leaves its own marks on the ruler of light.
Molecules absorb light at specific frequencies determined by their chemical structure. A frequency comb acts as a precision optical ruler — at 200 MHz spacing, OSCAii places hundreds of thousands of evenly spaced laser frequencies across the molecular fingerprint region.
When this comb light passes through breath, each molecule absorbs its own characteristic set of frequencies, leaving a distinct pattern in the transmitted light. Reading that pattern reveals which molecules are present and how strongly they absorb — giving both broad spectral coverage and high precision in a single measurement.
Peer-reviewed validation: Xing et al., CLEO 2025, SS122.6 — First compact single-cycle comb empowered dual-band IP-DFG mid-IR combs for breath analysis.
Two combs turn optical fingerprints into a real-time molecular readout.
Dual-comb spectroscopy works by combining two frequency combs with slightly different spacings. After one comb passes through the breath sample and both meet on a detector, the optical molecular fingerprints are converted into radio-frequency signals that standard electronics can read in real time.
OSCAii's advantage starts at the light source. Single-cycle pulses generate mid-infrared combs that span key molecular fingerprint windows — covering not just inorganic trace gases, but also the spectral regions where volatile organic compounds and functional-group vibrations leave their strongest signatures. The result is a massively parallel molecular readout: all species measured at once, rather than scanning one molecule or one wavelength at a time.
Peer-reviewed validation: Zhang and Xing, CLEO 2026, STH2H.7 — High-dynamic-range multi-species DCS with real-time coherent averaging, resolving CO, CO₂, NO, and H₂O in mixed gas samples and measuring CO from trace levels to 0.1% at 1 atm.
System specifications
| Parameter | Value |
|---|---|
| Spectral range (current) | 2–12 µm (Mid-IR) |
| Spectral range (Phase 2) | 2–25 µm |
| Dynamic range (current) | ppb to % — 4+ orders |
| Dynamic range (Phase 2) | ppt to % — 7+ orders |
| Resolution | 200 MHz real-time + sub-Hz with interleaving |
| Acquisition speed | Seconds-scale spectra, application dependent |
| Coherent averaging | 11,000 real-time coherent averages in <10 s |
| Gas interaction length | 32 m (current) |
| Moving parts | No mechanical delay lines |
| Frequency traceability | RF-referenced · TAI-traceable |
| Pulse duration | <7 fs single-cycle |
| Frequency stability | 1×10⁻¹⁸ @ 1 s · 1×10⁻²⁰ @ 1,000 s |
