Publications associated with Ultrafast quantum optics and optical metrology
Continuous phase stabilization and active interferometer control using two modes
JOURNAL OF MODERN OPTICS 59 (2012) 42-45
Adaptive slit beam shaping for direct laser written waveguides.
Opt Lett 37 (2012) 470-472
We demonstrate an improved method for fabricating optical waveguides in bulk materials by means of femtosecond laser writing. We use an LC spatial light modulator (SLM) to shape the beam focus by generating adaptive slit illumination in the pupil of the objective lens. A diffraction grating is applied in a strip across the SLM to simulate a slit, with the first diffracted order mapped onto the pupil plane of the objective lens while the zeroth order is blocked. This technique enables real-time control of the beam-shaping parameters during writing, facilitating the fabrication of more complicated structures than is possible using nonadaptive methods. Waveguides are demonstrated in fused silica with a coupling loss to single-mode fibers in the range of 0.2 to 0.5 dB and propagation loss <0.4 dB/cm.
Compact Continuous-Variable Entanglement Distillation
PHYSICAL REVIEW LETTERS 108 (2012) ARTN 060502
Macroscopic non-classical states and terahertz quantum processing in room-temperature diamond
Nature Photonics 6 (2012) 41-44
On-chip, photon-number-resolving, telecom-band detectors for scalable photonic information processing
Physical Review A 84 (2011) 060301(R)
Integration is currently the only feasible route towards scalable photonic quantum processing devices that are sufficiently complex to be genuinely useful in computing, metrology, and simulation. Embedded on-chip detection will be critical to such devices. We demonstrate an integrated photon-number resolving detector, operating in the telecom band at 1550 nm, employing an evanescently coupled design that allows it to be placed at arbitrary locations within a planar circuit. Up to 5 photons are resolved in the guided optical mode via absorption from the evanescent field into a tungsten transition-edge sensor. The detection efficiency is 7.2 \pm 0.5 %. The polarization sensitivity of the detector is also demonstrated. Detailed modeling of device designs shows a clear and feasible route to reaching high detection efficiencies.
Accuracy measurements and improvement for complete characterization of optical pulses from nonlinear processes via multiple spectral-shearing interferometry
OPTICS EXPRESS 19 (2011) 25355-25366
Real-World Quantum Sensors: Evaluating Resources for Precision Measurement
PHYS REV LETT 107 (2011) 113603
Lateral shearing interferometry of high-harmonic wavefronts
OPT LETT 36 (2011) 1746-1748
Entangling Macroscopic Diamonds at Room Temperature
Science 334 (2011) 6060
Quantum entanglement in the motion of macroscopic solid bodies has implications both for quantum technologies and foundational studies of the boundary between the quantum and classical worlds. Entanglement is usually fragile in room-temperature solids, owing to strong interactions both internally and with the noisy environment. We generated motional entanglement between vibrational states of two spatially separated, millimeter-sized diamonds at room temperature. By measuring strong nonclassical correlations between Raman-scattered photons, we showed that the quantum state of the diamonds has positive concurrence with 98% probability. Our results show that entanglement can persist in the classical context of moving macroscopic solids in ambient conditions.
From molecular control to quantum technology with the dynamic Stark effect
FARADAY DISCUSS 153 (2011) 321-342
A new transducer receive transfer function calibration method: application to microbubble backscattering cross-section measurements at high frequency.
IEEE Trans Ultrason Ferroelectr Freq Control 58 (2011) 1159-1168
When comparing acoustic scattering experiments with theory, the relationship between the pressure generated by a scatterer at the surface of a transducer and the induced voltage must be known. Methods have been previously proposed to measure the receive transfer function that rely on several assumptions. A new, experimental method for measuring the acoustic response of a spherically-focused transducer, using a hydrophone at twice the focal distance, is proposed that requires a minimum number of assumptions and calculations. The receive transfer function of a spherically-focused, high-frequency transducer was calculated, and found to be within 10% of the receive transfer function calculated assuming reciprocity. Further, using the receive transfer function, the effective backscattering cross-section of bound microbubbles interrogated at 30 MHz was measured to be, on average, 65% of the geometric backscattering cross-section, with significant size-independent variability. These results give insight into selecting the optimal microbubble size distribution for linear microbubble imaging at high frequencies.
Extending electron orbital precession to the molecular case: Use of orbital alignment for observation of wavepacket dynamics
PHYS REV A 83 (2011) 043419
Single-photon-level memory at room temperature
2011 Conference on Lasers and Electro-Optics: Laser Science to Photonic Applications, CLEO 2011 (2011)
On-chip, photon-number-resolving, telecommunication-band detectors for scalable photonic information processing
Physical Review A - Atomic, Molecular, and Optical Physics 84 (2011)
Photonic quantum memories
2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011 (2011)
Quantum metrology with imperfect states and detectors
Physical Review A - Atomic, Molecular, and Optical Physics 83 (2011)
Femtosecond to attosecond light pulses from a molecular modulator
NAT PHOTONICS 5 (2011) 665-672