Alessandro Restelli
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View article: Errors in PDH offset locking due to spurious spectral features
Errors in PDH offset locking due to spurious spectral features Open
The Pound-Drever-Hall (PDH) technique is widely used to stabilize the frequency of lasers. Here we report on a routinely underestimated source of error in PDH offset-locking: a shift in the lock point due to the unintended interaction betw…
View article: On-chip multi-timescale spatiotemporal optical synchronization
On-chip multi-timescale spatiotemporal optical synchronization Open
Mode locking is foundational to nonlinear optics, enabling advances in metrology, spectroscopy, and communications. However, it remains unexplored in nonharmonic, multi-timescale regimes. Here, we realize on-chip multi-timescale synchroniz…
View article: Spectrally-pure optical serrodyne modulation for continuously-tunable laser offset locking
Spectrally-pure optical serrodyne modulation for continuously-tunable laser offset locking Open
The comb-like spectrum added to laser light by an electro-optic modulator (EOM) finds use in a wide range of applications, including coherent optical communication, atomic spectroscopy, and laser frequency and phase stabilization. In some …
View article: Microheater hotspot engineering for spatially resolved and repeatable multi-level switching in foundry-processed phase change silicon photonics
Microheater hotspot engineering for spatially resolved and repeatable multi-level switching in foundry-processed phase change silicon photonics Open
View article: Highly squeezed nanophotonic quantum microcombs with broadband frequency tunability
Highly squeezed nanophotonic quantum microcombs with broadband frequency tunability Open
Squeezed light offers genuine quantum advantage in enhanced sensing and quantum computation; yet the level of squeezing or quantum noise reduction generated from nanophotonic chips has been limited. In addition to strong quantum noise redu…
View article: Spectrally-pure optical serrodyne modulation for continuously-tunable laser offset locking
Spectrally-pure optical serrodyne modulation for continuously-tunable laser offset locking Open
The comb-like spectrum added to laser light by an electro-optic modulator (EOM) finds use in a wide range of applications, including coherent optical communication, atomic spectroscopy, and laser frequency and phase stabilization. In some …
View article: Quadrature amplitude modulation for electronic sideband Pound-Drever-Hall locking
Quadrature amplitude modulation for electronic sideband Pound-Drever-Hall locking Open
The Pound-Drever-Hall (PDH) technique is routinely used to stabilize the frequency of a laser to a reference cavity. The electronic sideband (ESB) locking scheme, a PDH variant, helps bridge the frequency difference between the quantized f…
View article: Microheater hotspot engineering for repeatable multi-level switching in foundry-processed phase change silicon photonics
Microheater hotspot engineering for repeatable multi-level switching in foundry-processed phase change silicon photonics Open
Nonvolatile photonic integrated circuits employing phase change materials have relied either on optical switching mechanisms with precise multi-level control but poor scalability or electrical switching with seamless integration and scalab…
View article: Microheater hotspot engineering for repeatable multi-level switching in foundry-processed phase change silicon photonics
Microheater hotspot engineering for repeatable multi-level switching in foundry-processed phase change silicon photonics Open
Nonvolatile photonic integrated circuits employing phase change materials have relied either on optical switching mechanisms with precise multi-level control but poor scalability or electrical switching with seamless integration and scalab…
View article: A compact and open-source microcontroller-based rapid auto-alignment system
A compact and open-source microcontroller-based rapid auto-alignment system Open
Maintaining stable and precise alignment of a laser beam is crucial in many optical setups. In this work, we present a microcontroller-based rapid auto-alignment system that detects and corrects for drifts in a laser beam trajectory using …
View article: A 20 A bipolar current source with 140 <i>μ</i>A noise over 100 kHz bandwidth
A 20 A bipolar current source with 140 <i>μ</i>A noise over 100 kHz bandwidth Open
The precise control of direct current (dc) magnetic fields is crucial in a wide range of experimental platforms, from ultracold quantum gases and nuclear magnetic resonance to precision measurements. In each of these cases, the Zeeman effe…
View article: Nanocryotron ripple counter integrated with a superconducting nanowire single-photon detector for megapixel arrays
Nanocryotron ripple counter integrated with a superconducting nanowire single-photon detector for megapixel arrays Open
Decreasing the number of cables that bring heat into the cryostat is a critical issue for all cryoelectronic devices. Especially, arrays of superconducting nanowire single-photon detectors (SNSPDs) could require more than $10^6$ readout li…
View article: Programmable system on chip for controlling an atomic physics experiment
Programmable system on chip for controlling an atomic physics experiment Open
Most atomic physics experiments are controlled by a digital pattern generator used to synchronize all equipment by providing triggers and clocks. Recently, the availability of well-documented open-source development tools has lifted the ba…
View article: Thermal Stability Evaluation of Nitroalkanes with Differential Scanning Calorimetry
Thermal Stability Evaluation of Nitroalkanes with Differential Scanning Calorimetry Open
The thermal stability of a set of aliphatic nitroalkanes, comprising primary and secondary nitroalkanes, with short and long linear chains or cyclic, was tested by differential scanning calorimetry (DSC) analysis, for comparative purposes.…
View article: A radiofrequency voltage-controlled current source for quantum spin manipulation
A radiofrequency voltage-controlled current source for quantum spin manipulation Open
We present a wide-bandwidth, voltage-controlled current source that is easily integrated with radiofrequency magnetic field coils. Our design uses current feedback to compensate for the frequency-dependent impedance of a radiofrequency ant…
View article: The Recurrent Processing Unit: Hardware for High Speed Machine Learning
The Recurrent Processing Unit: Hardware for High Speed Machine Learning Open
Machine learning applications are computationally demanding and power intensive. Hardware acceleration of these software tools is a natural step being explored using various technologies. A recurrent processing unit (RPU) is fast and power…
View article: JQIamo/aom-driver: Fix LCD burnout
JQIamo/aom-driver: Fix LCD burnout Open
I've reduced the voltage of the regulator that powers the LCD. The lower voltage should prevent the LCD backlight from burning out. DSB
View article: Temporal and spectral manipulations of correlated photons using a time lens
Temporal and spectral manipulations of correlated photons using a time lens Open
A common challenge in quantum information processing with photons is the limited ability to manipulate and measure correlated states. An example is the inability to measure picosecond scale temporal correlations of a multi-photon state, gi…
View article: An ultra-low noise, high-voltage piezo-driver
An ultra-low noise, high-voltage piezo-driver Open
We present an ultra-low noise, high-voltage driver suited for use with piezoelectric actuators and other low-current applications. The architecture uses a flyback switching regulator to generate up to 250 V in our current design, with an o…
View article: Active stabilization of ion trap radiofrequency potentials
Active stabilization of ion trap radiofrequency potentials Open
We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1…
View article: Photon-efficient quantum cryptography with pulse-position modulation
Photon-efficient quantum cryptography with pulse-position modulation Open
The binary (one-bit-per-photon) encoding that most existing quantum key distribution (QKD) protocols employ puts a fundamental limit on their achievable key rates, especially under high channel loss conditions associated with long-distance…
View article: Harnessing high-dimensional hyperentanglement through a biphoton frequency comb
Harnessing high-dimensional hyperentanglement through a biphoton frequency comb Open
Quantum entanglement is a fundamental resource for secure information processing and communications, where hyperentanglement or high-dimensional entanglement has been separately proposed towards high data capacity and error resilience. The…
View article: Photon-efficient quantum key distribution using time–energy entanglement with high-dimensional encoding
Photon-efficient quantum key distribution using time–energy entanglement with high-dimensional encoding Open
Conventional quantum key distribution (QKD) typically uses binary encoding based on photon polarization or time-bin degrees of freedom and achieves a key capacity of at most one bit per photon. Under photon-starved conditions the rate of d…
View article: Photon-efficient quantum key distribution using time–energy entanglement with high-dimensional encoding
Photon-efficient quantum key distribution using time–energy entanglement with high-dimensional encoding Open
Conventional quantum key distribution (QKD) typically uses binary encoding based on photon polarization or time-bin degrees of freedom and achieves a key capacity of at most one bit per photon. Under photon-starved conditions the rate of d…