An open-source high-frequency lock-in amplifier

Stimpson, G. A.; Skilbeck, M. S.; Patel, R. L.; Green, Ben L.; Morley, Gavin W.

doi:10.1063/1.5083797

Cited by 44 publications

(17 citation statements)

References 30 publications

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“…We used as lock-in reference a modulation frequency of 1.333 kHz, which was also used as a square-wave envelope for the QCL pulses. ∆u could be inferred from the lock-in reading (V LI ) via the relation ∆u = (π √ 2/2) × V LI /G [29], where the pre-factor π √ 2/2 took into account that the lock-in measured the root mean square of the fundamental sine wave Fourier component of the square wave [45] produced by the QCL modulation. Figure 3c shows the dependence of the photocurrent recorded with one of the NW-FET detectors as a function of P o , demonstrating the NW-FET linearity.…”

Section: Antenna Characterizationmentioning

confidence: 99%

Semiconductor Nanowire Field-Effect Transistors as Sensitive Detectors in the Far-Infrared

et al. 2021

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Engineering detection dynamics in nanoscale receivers that operate in the far infrared (frequencies in the range 0.1–10 THz) is a challenging task that, however, can open intriguing perspectives for targeted applications in quantum science, biomedicine, space science, tomography, security, process and quality control. Here, we exploited InAs nanowires (NWs) to engineer antenna-coupled THz photodetectors that operated as efficient bolometers or photo thermoelectric receivers at room temperature. We controlled the core detection mechanism by design, through the different architectures of an on-chip resonant antenna, or dynamically, by varying the NW carrier density through electrostatic gating. Noise equivalent powers as low as 670 pWHz−1/2 with 1 µs response time at 2.8 THz were reached.

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Section: Antenna Characterizationmentioning

confidence: 99%

Semiconductor Nanowire Field-Effect Transistors as Sensitive Detectors in the Far-Infrared

et al. 2021

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“…The digital feedback system is implemented using the STEMlab 125-14 platform 33 (formerly: Red Pitaya) for analog/digital conversion and signal processing. It was already successfully used in various real-time applications in physics, including laser and frequency comb stabilization 34,35 and lock in amplifiers 36 , but to our knowledge has never been used for the direct manipulation of single ions. The STEMlab is built around a Zynq 7000 37 system on chip (SoC), combining a dual core ARM A9 CPU with FPGA fabric on the same device.…”

Section: Implementation Of the Digital Feedback Systemmentioning

confidence: 99%

A Digital Feedback System for Advanced Ion Manipulation Techniques in Penning Traps

Herkenhoff,

Door,

Filianin

et al. 2021

Preprint

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The possibility to apply active feedback to a single ion in a Penning trap using a fully digital system is demonstrated. Previously realized feedback systems rely on analog circuits that are susceptible to environmental fluctuations and long term drifts, as well as being limited to the specific task they were designed for. The presented system is implemented using an FPGA-based platform (STEMlab), offering greater flexibility, higher temporal stability and the possibility for highly dynamic variation of feedback parameters. The system's capabilities were demonstrated by applying feedback to the ion detection system primarily consisting of a resonant circuit. This allowed shifts in its resonance frequency of up to several kHz and free modification of its quality factor within two orders of magnitude, which reduces the temperature of a single ion by a factor of 6. Furthermore, a phase-sensitive detection technique for the axial ion oscillation was implemented, which reduces the current measurement time by two orders of magnitude while simultaneously eliminating model-related systematic uncertainties. The use of FPGA technology allowed the implementation of a fully-featured data acquisition system, making it possible to realize feedback techniques that require constant monitoring of the ion signal. This was successfully used to implement a single-ion self-excited oscillator.The following article has been accepted by Review of Scientific Instruments. After it is published, it will be found at https://aip.scitation.org/journal/rsi.

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“…The input stage is designed to compare a photodetector voltage with an external reference level. A stepwise-variable amplification (1,2,4,8,16) can be selected for the photodetector input. The reference signal and the amplified photodetector signal are subtracted.…”

Section: Hardware Designmentioning

confidence: 99%

“…[3] The STEMlab platform has already been successfully applied to control tasks in optical experiments, such as optical phase locking, [4,5] laser frequency comb stabilization, [6] second harmonic generation, [7] or as a lock-in amplifier. [8] In our work, the STEMlab hardware is embedded in two different analog interfaces that facilitate the application to a considerable variety of laser systems. We provide a characterization of both systems.…”

Section: Introductionmentioning

confidence: 99%

Digital laser frequency and intensity stabilization based on the STEMlab platform (originally Red Pitaya)

Preuschoff

Schlosser

Birkl

2020

Review of Scientific Instruments

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We report on the development, implementation, and characterization of digital controllers for laser frequency stabilization as well as intensity stabilization and control. Our design is based on the STEMlab (originally Red Pitaya) platform. The presented analog hardware interfaces provide all necessary functionalities for the designated applications and can be integrated in standard 19-inch rack mount units. Printed circuit board layouts are made available as an open-source project.[1, 2] A detailed characterization shows that the bandwidth (1.25 MHz) and the noise performance of the controllers are limited by the STEMlab system and not affected by the supplementary hardware. Frequency stabilization of a diode laser system resulting in a linewidth of 52(1) kHz (FWHM) is demonstrated. Intensity control to the 1 × 10 −3 level with sub-microsecond rise and fall times based on an acousto-optic modulator as actuator is achieved.

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An open-source high-frequency lock-in amplifier

Cited by 44 publications

References 30 publications

Semiconductor Nanowire Field-Effect Transistors as Sensitive Detectors in the Far-Infrared

Semiconductor Nanowire Field-Effect Transistors as Sensitive Detectors in the Far-Infrared

A Digital Feedback System for Advanced Ion Manipulation Techniques in Penning Traps

Digital laser frequency and intensity stabilization based on the STEMlab platform (originally Red Pitaya)

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