Driven by a single HELIOS-20W-HP femtosecond pump source, WaveQuanta brought two AURORA-HP OPAs, one AURORA-SHG and two AURORA-DFG modules online in a single on-site commissioning run — covering 315 nm to 4.3 µm of continuously tunable femtosecond output (with a modular path to 10 µm), spanning more than six octaves. This is the largest and most architecturally complex ultrafast spectroscopy platform WaveQuanta has shipped to date.

1.  Why "full spectrum" matters

Researchers tend to see the electromagnetic spectrum as a multi-storey building. The UV floor (< 400 nm) reveals electronic transitions and aromatic π–π* dynamics. The visible floor (400–700 nm) reads out pigments, quantum dots and the band-edge absorption of perovskites. The near-IR floor (700–2500 nm) tracks semiconductor carrier dynamics and low-gap organic semiconductors. The mid-IR floor (2.5–10 µm) listens to bond vibrations and the subtle reshaping of molecular conformations.

Frontline ultrafast spectroscopists rarely live on just one floor. In a perovskite solar cell, the same experiment may need to watch exciton and free-carrier generation at 400–800 nm, follow polaron formation at 1000–1600 nm, and probe MA⁺/FA⁺ cation vibrations at 3–6 µm — all in one pump-probe sequence, all tied to the same femtosecond clock.

That is why a "full-spectrum femtosecond source" — continuously tunable from deep UV to deep mid-IR — is becoming a hard requirement in top-tier ultrafast labs. It is not just about broader bandwidth: it lets one group, on one workstation, with one software stack, run experiments that previously required collaboration across multiple labs.

2.  Why "dual OPA + SHG + DFG" is the only way to 315 nm – 10 µm

Start with the physics. A single OPA pumped by a 1030 nm Yb femtosecond laser generates signal and idler beams via parametric down-conversion in a BBO crystal. Phase-matching restricts the direct output to two arms: 630–1030 nm (Signal) and 1030–2600 nm (Idler). In other words, a single OPA reaches no shorter than 630 nm and no longer than 2600 nm. The 315 nm UV and 10 µm deep mid-IR endpoints simply lie outside its range.

Extending the spectrum at both ends requires two additional nonlinear stages:

■ SHG (second-harmonic generation) — doubling the OPA signal/idler compresses the wavelength down to 315–630 nm (UV/Vis). On the WaveQuanta platform this is the AURORA-SHG module.

■ DFG (difference-frequency generation) — mixing the OPA idler with a clean residual 1030 nm beam pushes the wavelength out to 3–10 µm (deep mid-IR). On our platform this is the AURORA-DFG module.

Why two OPAs, instead of one OPA driving both SHG and DFG?

In principle, you could split a single OPA's signal into SHG and its idler into DFG. In practice, the "single-OPA, dual-use" configuration breaks down in three irreconcilable ways for serious ultrafast research:

■ (1) Energy is halved. OPA output power is finite (the signal peak in this project is around 600 mW). Splitting it between SHG and DFG starves both conversion stages, and conversion efficiency collapses — most severely on the long-wavelength side beyond 4 µm.

■ (2) Independent tuning is lost. A full-spectrum TA experiment routinely needs UV pump + MIR probe simultaneously. If SHG and DFG share one OPA, tuning the SHG to 375 nm locks the idler — and with it the 3 / 4 / 6 µm DFG output. The two arms become forcibly coupled in wavelength.

■ (3) Timing and noise cross-talk. Shot-to-shot fluctuations from the shared OPA are amplified through both SHG and DFG stages, appearing simultaneously on the UV and MIR arms. No reference channel can suppress correlated noise between them.

That is why this project uses parallel dual-OPA architecture, with each OPA owning a dedicated nonlinear conversion module — completely decoupling the short-wavelength and long-wavelength chains:

■ AURORA-HP #1 (+ AURORA-SHG) — short-wavelength chain: Signal 630–1030 nm + Idler 1030–2600 nm + SHG 315–630 nm. Covers the entire UV/Vis range.

■ AURORA-HP #2 (+ AURORA-DFG × 2) — long-wavelength chain: Signal 630–1030 nm + Idler 1030–2600 nm + DFG 3–10 µm (verified to 4.3 µm at factory acceptance). Covers NIR/MIR/deep-MIR.

Both OPAs are pumped by the same HELIOS-20W-HP and synchronized by a shared BME 8-channel timing system — yet remain fully independent in wavelength selection, energy control and noise transport. A single TA bench can therefore deliver "375 nm UV pump" and "4 µm MIR probe" simultaneously, with both arms freely tunable. No single-OPA configuration can match this.

A dual-OPA architecture isn't "twice as expensive" — it is "twice as free". For full-spectrum ultrafast spectroscopy, that extra degree of freedom is often the difference between data that gets published and data that gets discarded. Energy conservation (ωₚ = ωₛ + ωᵢ) and phase-matching (Δk ≈ 0) decide which wavelengths can be generated efficiently; the real engineering challenge is keeping two independent nonlinear conversion chains locked to the same stable master clock and holding < 1 % drift across ten-plus hours of continuous operation.

3.  System architecture: how one HELIOS feeds two OPAs + DFG + SHG

The real bottleneck in building a full-spectrum platform is rarely the OPA itself — it is pump distribution. Driving two OPAs, two DFG modules and one SHG module from the same master laser turns the splitting architecture and energy budget into the defining engineering problem.

On this platform, the HELIOS-20W-HP master laser provides 21.54 W / 431 µJ @ 50 kHz, then a carefully designed four-way splitting network feeds both AURORA-HP units:

■ Path ① — 216 µJ (10.8 W @ 50 kHz), passed through an EOM to drop the rep rate from 50 kHz to 25 kHz, then pumps AURORA-HP #1 with the AURORA-SHG module attached. This drives the UV-Vis 315–630 nm short-wavelength chain.

■ Path ② — 150 µJ (7.5 W @ 50 kHz), pumps AURORA-HP #2 with two AURORA-DFG modules attached. This drives the NIR / MIR / deep mid-IR long-wavelength chain.

■ Paths ③ and ④ — roughly 30 µJ each, reserved for white-light continuum generation, reference arms and future expansion (a third OPA or THz generation).

In engineering shorthand, this is the "single master, multi-split, multi-OPA, modular" paradigm typical of high-end ultrafast labs: every beam path tunes its own energy and timing, all synchronized through a BME 8-channel timing system, and remotely orchestrated by an integrated industrial PC.

4.  Measured performance: hard numbers from one factory acceptance run

All numbers below come from WaveQuanta's factory acceptance test for a leading Chinese research university's ultrafast spectroscopy group (April 2026). All five modules were brought online in a single commissioning run; every curve below is reproduced from the final customer-acceptance report.

4.1  HELIOS-20W-HP master laser

The master laser operates stably at 21.54 W average power, 431 µJ single-pulse energy, 231 fs FWHM (PulseCheck NX S09706 autocorrelator @ 50 kHz). 16-hour continuous burn-in: power stability ≈ 0.14 % RMS, pointing stability 5.16 µrad (2.58 µm RMS at a 500 mm focusing lens), pre-pulse contrast 1000:1, beam quality M²x = 1.187 / M²y = 1.110, beam diameter 5.0 mm.

Fig. 1  HELIOS-20W-HP output spectrum · center wavelength 1036.7 nm (YOKOGAWA AQ6370B)

Fig. 2  HELIOS-20W-HP intensity autocorrelation · FWHM = 231 fs @ 50 kHz (PulseCheck NX S09706 autocorrelator)

Fig. 3  HELIOS-20W-HP 16-hour continuous power stability · 21.54 W average · RMS ≈ 0.14 %

Fig. 4  HELIOS-20W-HP 16-hour pointing stability · 5.16 µrad (RMS = 2.58 µm at 500 mm focal length)

4.2  AURORA-HP #2 + AURORA-DFG (long-wavelength chain · NIR / MIR / deep MIR)

The long-wavelength chain is driven by AURORA-HP #2, pumped at 7.5 W / 150 µJ @ 50 kHz. The OPA signal and idler are paired with two AURORA-DFG modules that mix the idler with the clean residual 1030 nm beam, extending the spectrum into the deep mid-IR. Measured at factory acceptance:

■ Signal (630–1030 nm): peak ~619 mW at 740 nm (8.25 % peak energy-conversion efficiency); ≥ 570 mW maintained across 700–800 nm.

■ Idler (1030–2600 nm): peak ~485 mW at 1050 nm; still ≈ 300 mW at 1.5 µm; usable tens-of-mW output sustained out to 2.5 µm.

■ DFG (2.6–4.3 µm verified on this build): peak ~155 mW at 3.1 µm; ≥ 130 mW maintained across 3.0–3.5 µm. The modular architecture supports customer-side extension toward 10 µm.

■ Long-term stability: 16 h continuous burn-in, OPA signal averaging ≈ 440 mW with no visible drift.

Fig. 5  AURORA-HP #2 (+ DFG) tuning curve · Signal / Idler / DFG three-band output (green / yellow / pink)

Fig. 6  AURORA-HP #2 + DFG long-wavelength chain — 16-hour long-term power stability

4.3  AURORA-HP #1 + AURORA-SHG (short-wavelength chain · UV / Vis)

The short-wavelength chain is driven by AURORA-HP #1, pumped at 10.8 W / 216 µJ @ 50 kHz with an EOM downconverting the rep rate to 25 kHz. The OPA signal and idler then feed the AURORA-SHG module to produce two additional channels — SHS (signal-doubled) and SHI (idler-doubled) — covering UV and visible. Measured at factory acceptance:

■ Signal (630–1030 nm): peak ~575 mW at 750 nm (10.64 % peak energy-conversion efficiency — the highest of the two OPAs on this platform); ≥ 510 mW maintained across 680–820 nm.

■ Idler (1030–2560 nm): peak ~300 mW at 1040 nm; ≈ 170 mW maintained across 1.3–1.7 µm, more than enough for OH / NH / CH overtone probing.

■ SHS (315–510 nm, signal-doubled): peak ~150 mW at 375 nm (2.77 % peak efficiency), covering the critical UV window for aromatic π–π* transitions.

■ SHI (520–630 nm, idler-doubled): peak ~66 mW at 520 nm, filling in the green-orange band for dyes and organic semiconductors.

■ Long-term stability: 16 h continuous burn-in, OPA signal averaging ≈ 440 mW with no visible drift.

Fig. 7  AURORA-HP #1 (+ SHG) four-channel tuning curve (Signal / Idler / SHS / SHI)

Fig. 8  AURORA-HP #1 + SHG short-wavelength chain — 16-hour long-term power stability

Combined, the curves above confirm continuous tunable output from 315 nm to 4.3 µm at factory acceptance, with a modular upgrade path to 10 µm — enough for exciton dynamics, polaron spectroscopy, vibrational spectroscopy and catalysis interface studies to all run on the same platform.

5.  Delivery case: a leading Chinese research university

All measurements above come from WaveQuanta's April 2026 "five-module" factory acceptance test for the ultrafast spectroscopy group at a leading Chinese research university — the largest and most architecturally complex full-spectrum ultrafast platform WaveQuanta has integrated to date.

Bill of delivery:

■ HELIOS-20W-HP femtosecond master laser × 1

■ AURORA-HP femtosecond OPA × 2 (Signal 630–1030 nm, Idler 1030–2600 nm)

■ AURORA-SHG UV-Vis doubling module × 1 (315–630 nm)

■ AURORA-DFG deep mid-IR difference-frequency module × 2 (3–10 µm design, 2.6–4.3 µm verified on this build)

■ EOM rep-rate divider (50 → 25 kHz), BME 8-channel timing system, integrated industrial PC for remote control

Customer research directions:

Excited-state relaxation and charge separation in organic photovoltaics (OSCs); MA⁺/FA⁺ cation vibrational coupling in perovskite solar cells; ultrafast carrier dynamics in semiconductor quantum structures; femtosecond-IR diagnostics of catalytic intermediates at surfaces.

What makes this delivery notable:

■ (i) The first domestically integrated ultrafast source platform designed for full 315 nm – 10 µm coverage (315 nm – 4.3 µm verified at acceptance), with the entire chain integrated by a single Chinese supplier.

■ (ii) The four-way splitting plus EOM downconversion architecture was custom-designed around the group's experiment requirements, and all five modules came up in a single on-site commissioning.

■ (iii) The AURORA-DFG modules were co-developed with the customer: the customer supplied the nonlinear crystal and beam-routing scheme, WaveQuanta delivered the integrated opto-mechanical-electronic system — a working example of next-generation industry-academia co-development.

For the customer, "five modules online in one commissioning run" compresses the gap between delivery and first publishable data. For WaveQuanta, it validates the "HELIOS + wide-tuning OPA + SHG + DFG" product stack as a reproducible standard offering for real-world ultrafast research.

6.  Where it pays off — application landscape

For an ultrafast spectroscopy group, "full spectrum" means one hardware stack covers cross-energy-scale questions. The directions that benefit most immediately:

■ Perovskite solar cells — track exciton generation and band-edge bleaching in the visible, polaron dynamics in the NIR, and MA⁺/FA⁺ cation vibrational coupling in the 3–6 µm mid-IR. One experiment answers the central question of how photo-generated carriers couple to the lattice.

■ Organic photovoltaics (OSCs) — high time-resolution UV-Vis TA captures excited-state relaxation and CT-state formation; parallel MIR readout monitors backbone vibrational coupling.

■ Surface catalysis and interfacial chemistry — 3–10 µm DFG enables time-resolved IR spectroscopy (fs-TR-IR) that directly catches the transient IR fingerprints of catalytic intermediates.

■ Semiconductors / 2D materials / quantum dots — multi-exciton dynamics, exciton-phonon coupling, hot-carrier cooling in TMDs (MoS₂, WSe₂) and quantum dots demand simultaneous UV-through-MIR probing.

■ 2D-IR and multidimensional IR — the 3–10 µm DFG output is the core light source for 2D-IR / fs-TR-IR studies of protein secondary structure, hydrogen-bond networks and liquid-interface ultrafast dynamics.

7.  Closing thought

A full-spectrum OPA is not "more boxes on the optical table" — it is the co-design of pump-source energy, stability, beam-splitting purity and the phase-matching precision of every nonlinear stage. This delivery shows that an industrial-grade Yb femtosecond master, paired with modular OPA, SHG and DFG units, can in fact cover 315 nm to 4.3 µm of continuously tunable femtosecond light on a single optical table (with a clear modular path to 10 µm) — finally bringing the "one platform, one spectrum, one experiment" workflow within reach of an ultrafast spectroscopy lab.

As domestic femtosecond platforms mature and modular capabilities continue to expand, "315 nm to 10 µm full-spectrum ultrafast spectroscopy" will move from being a luxury reserved for a handful of top labs to the standard configuration for many.

—  WaveQuanta  |  Make Every Femtosecond Count.  —

If you are building a TA / pump-probe / 2D-IR / full-spectrum ultrafast experiment, DM the WaveQuanta Applications Engineering team for the detailed acceptance report and a customized beam-routing proposal.