The QP³ Lab builds integrated circuits from state-of-the-art nanoscale materials that couple photons, phonons, charge carriers and external fields — enabling new tools for quantum computing, networking, signal processing, and precision sensing.
Strain sits at the centre: every coupling we engineer runs through mechanics, or between the carriers around it. Bright text names the mechanism, grey text what it enables.
Photonic integrated circuits that generate, route, and modulate light for quantum information — with piezo-optomechanics providing low-power, cryo-compatible control.
Chip-scale beam delivery, switching, and modulation for atomic qubits. Piezo-actuated photonics provides fast, low-power optical control that scales to the thousands of channels trapped-atom and trapped-ion processors will demand.
A two-photon Raman gate needs a pair of optical tones split by the qubit's microwave transition — typically several gigahertz. Producing that splitting normally means bulk modulators sitting outside the vacuum chamber. Gigahertz acousto-optic modulation of visible light in a CMOS-fabricated photonic circuit generates both tones on chip instead, at the same place the light is delivered to the ion.
Many of the most useful atomic transitions sit in the ultraviolet, exactly where silicon nitride stops being transparent. Low-loss alumina waveguides keep working there, and piezo-optomechanical actuation tunes and modulates them without dissipating heat. CMOS-fabricated alumina circuits bring UV light under the same chip-scale control we already have in the visible — reaching ion species that conventional integrated photonics cannot.
Heterogeneous integration of diamond color centers with piezo-optomechanical circuits, linking long-lived spin qubits to photons and phonons for on-chip quantum memories, repeaters, and transducers.
Low-confinement silicon nitride waveguides drive propagation loss into the ultra-low regime, and piezo-optomechanical actuators tune them without dissipating heat. The same platform carries nonlinear processes — frequency combs, wavelength conversion, squeezed light — alongside reconfigurable circuits programmable channel by channel, which is what quantum systems demand at scale.
MEMS cantilevers built in a CMOS foundry hold an optical phase after the drive is removed, turning a photonic circuit into memory. Electrostatic and piezoelectric actuation together give multi-level, strain-latched storage with billion-cycle endurance — the basis for in-memory optical computing and large reconfigurable meshes.
Sound at gigahertz frequencies, guided and amplified on a chip. Phonons are slow, compact, and couple to nearly everything — we make them active circuit elements rather than passive delay lines.
Drifting electrons in a semiconductor can amplify a co-propagating acoustic wave and attenuate the reverse one. We use this acoustoelectric effect to build phononic amplifiers, isolators, and circulators with gain — components RF acoustics has never had. We also work out the noise floor these amplifiers can reach, down to the quantum limit set by the acoustoelectric vacuum itself.
Acoustic gain inside an acoustic cavity gives a laser made of sound. Driving DC current through a semiconductor film on a lithium niobate SAW resonator pushes electrons faster than the speed of sound, amplifying the cavity mode until it crosses threshold into self-sustained coherent oscillation — gigahertz frequencies, dramatic linewidth narrowing, in under 0.15 mm². First demonstrated in Wendt et al., Nature 649, 597 (2026).
Operating phononic circuits in the quantum regime: single-phonon sources, phononic waveguides and resonators coupled to qubits, and mechanical modes as compact quantum memories and interconnects.
A piezoelectric transducer lets a superconducting qubit exchange excitations with a phononic resonator, trading a centimetre-scale microwave mode for an acoustic one thousands of times smaller. Building the AlScN transducer and the 4H-SiC phononic circuit on a single unreleased substrate keeps acoustic loss low while staying compatible with wafer-scale fabrication — a route to compact quantum memories and interconnects operating at millikelvin temperatures.
When photons and phonons share a waveguide — and acoustoelectric gain removes the acoustic loss — entirely new classes of chip-scale RF-photonic processors become possible.
Acousto-optic modulation is powerful but lossy; acoustoelectric gain flips the sign. By amplifying the acoustic wave as it scatters light, we realize traveling-wave amplification and low-power modulation in a single hybrid device.
A hybrid optical and acoustic mode-locked laser. An optical cavity and an acoustic cavity share the same waveguide, and acoustoelectric gain sustains an acoustic mode tuned to the optical free spectral range, so the sound wave phase-locks the optical modes to one another. The result is a self-starting pulse train and a coherent frequency comb generated entirely on chip, with no external modulator.
Optomechanical transduction turns tiny forces, fields, and photons into measurable optical signals — with sensitivity that approaches, and is calibrated by, fundamental quantum limits.
Accelerometers and gyroscopes that read out a mechanical test mass with light, delivering self-calibrated, navigation-grade inertial sensing in a chip-scale package.
An absorbed infrared photon warms a mechanical resonator and shifts its frequency, so each oscillator becomes an uncooled infrared pixel read out optically rather than electrically. Slotted photonic crystal cavities fabricated in a high-volume CMOS foundry supply the sensitivity, and piezoelectric actuation sets each pixel's operating point — 3.87 THz of resonance tuning at 40 V, raising the optomechanical coupling rate from 160 to 500 GHz/nm.
Magnetostrictive materials convert magnetic fields into strain that optomechanical cavities read out with extreme precision — compact, room-temperature magnetometry without shielding.
Conventional ultrasound resolution is capped by the acoustic wavelength. Pushing transduction to gigahertz frequencies shrinks that wavelength below a micron, and optomechanical readout is sensitive enough to detect the returning echoes — opening a route to imaging structure inside a single cell.
Absorbed X-rays deposit heat and momentum in a mechanical resonator; optical readout resolves the resulting motion, opening a path to high-resolution, chip-scale X-ray detection.
Color-center spins in diamond, coupled to strain and integrated photonics, sense magnetic fields, temperature, and rotation at the nanoscale — quantum sensors built into the fabric of our devices.
Physicists and engineers spanning nanofabrication, quantum optics, RF acoustics, and precision measurement.
Papers, appointments, and recognition.
The paper demonstrates a fiber-packaged accelerometer that pairs a differential strain-sensing Mach–Zehnder interferometer with an ultra-rigid bulk-micromachined proof mass (93.4 kHz fundamental, 22.5 pm/g). Despite that rigidity it resolves 4.2 µg/√Hz, holds a bias instability of 6.3 µg at 243 seconds, and has a clear path to 330 ng/√Hz through improved fiber-to-chip coupling — all without needing an exotic laser source.
Read more →Congratulations to QP³ PhD students John Mack and Will Roberts for successfully passing their comprehensive exams on Thursday, August 13.
New preprint: an analog-programmable photonic memristor built from micro-electromechanical cantilevers on low-loss silicon nitride, requiring no back-end materials integration. Electrostatic and piezoelectric actuation give up to 5-bit phase storage, 50 kbit/s programming, strain-assisted retention beyond an hour, and endurance past a billion cycles.
Read more →A monolithic route to joining superconducting quantum circuits with low-loss gigahertz phonons on a single unreleased substrate — the material platform underpinning our quantum phononics program.
Read more →What happens to the phonon vacuum when a drift current pushes an acoustoelectric system out of equilibrium? This work sets the thermodynamic and quantum-noise framework that determines how quiet an acoustoelectric amplifier can ultimately be.
Read more →Design study for gigahertz optomechanical ultrasound transduction, where the acoustic wavelength falls below a micron and optical readout recovers the echo — a path toward imaging inside individual cells.
Read more →New preprint: 200 mm photonic wafers built directly on completed CMOS driver wafers, with more than two million electrical connections per die at a 6.4 µm electrode pitch. We introduce segmented photonic digital-to-analog converters and program phase shifters, interferometers, routing trees, and ring resonators over a standard HDMI interface — a path to wafer-scale electronic control of quantum and classical POMPICs.
Read more →Our chip-to-world beam scanning work appeared in Nature 651, 356 (2026). A nanoscale waveguide on a piezoelectric cantilever curls ~90° out of plane in under 0.1 mm², emitting a diffraction-limited beam and scanning it in 2D — sidestepping the trade-off between actuator mass and aperture size that has long constrained micromechanical scanners. Joint work with MIT, MITRE, and Sandia through the Quantum Moonshot Program.
Read more →A lithium niobate SAW resonator with an internal, DC-injected semiconductor gain medium in under 0.15 mm² crosses threshold into self-sustained coherent oscillation at 1 GHz, with linewidth narrowing below 100 Hz. Nature 649, 597 (2026). Led by graduate student Alexander Wendt; covered by CU Boulder Today and ScienceDaily.
Read more →Published in Nature Communications: GHz-frequency acousto-optic phase modulation of visible light in a photonic circuit built in a 200 mm CMOS foundry — a key step toward wafer-scale optical control of atomic and ionic qubits.
Read more →The lab joins CU Boulder’s Department of Electrical, Computer and Energy Engineering, where the endowed chair supports work spanning ultra-scalable photonics, nano-optomechanics, and phononics — alongside CU’s CUbit Quantum Initiative and the new National Quantum Nanofab facility.
Read more →Following the 2023 DARPA Young Faculty Award, the Director’s Fellowship extends support for our work on acoustoelectric and piezo-optomechanical device platforms.
Synthetic semiconductor–piezoelectric heterostructures make phonons interact with each other far more strongly than in any conventional material, opening a route to compact, high-efficiency RF signal processing. Nature Materials 23, 1386 (2024).
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