Real-Time Data-Acquisition Platform for Pulsed Measurements

Anuvab Nandi, Samiran Chakraborti, Jain, Yashvardhan +6 more

Ensembles of nitrogen vacancy (NV) defect centers in diamond have attracted considerable interest for fundamental studies and applications in quantum sensing and quantum information processing. Pulsed optically detected magnetic resonance (ODMR) and related pulse-sequence protocols are essential for the coherent manipulation and characterization of the NV spins. Here, we introduce a novel framework for analyzing pulsed ODMR data acquisition and subsequent processing from the perspective of digital signal processing (DSP). As a central part of this approach, we model the data processing procedure as an effective digital bandpass filter that suppresses a broad range of noise spectral components, thereby reducing the noise in the processed data. This analysis identifies an intermediate frequency (IF) band whose spectral contribution to this noise is maximum. The proposed DSP-based analysis is experimentally validated using an oscilloscope based acquisition method, and is also applied to optimize key measurement parameters. In particular, the introduction of an analog low pass filter in the signal path is shown to remove aliasing of noise into the IF band, and thus improve signal quality. Our results also establish the oscilloscope as a viable data acquisition device for pulsed ODMR, with practical advantages including on-board waveform averaging, real-time signal visualization, and simplified system debugging. The proposed framework can be extended to other detection techniques and material platforms for ODMR.

Riccardo Borgani, David B. Haviland

Hossein Kavianipour, C. Böhm, Mohamed Bourennane

In this paper we present the data acquisition (DAQ) system for a multichannel coincidence photon counter where this DAQ is optimized for a small coincidence window, high speed data retrieving without reduction and parallel data processing. For single photon detection we use Avalanche Photodiodes (APD) which are practical tools for detection in quantum optics and photonics quantum information experiments. However they introduce noise into the measurements originating from their dark count detection and after pulsing. One way to limit this contribution is to decrease the time window in which the coincidence detection measurement is performed. We have developed this DAQ based entirely on a standard Field Programmable Gate Array (FPGA) where the width of the coincidence time window is in the sub-nanosecond range. The same unit is also responsible for sending the result to the User Interface (UI). The communication between the UI and the FPGA platform is through a single link Peripheral Component Interconnect Express (PCIe) by means of streaming DMA. Our DAQ is developed for Xilinx Spartan-6 devices but other devices are also supported. A Linux driver with all necessary functionality to communicate with the DAQ as well as the UI is also developed. The use of our unit can be extended for other detection counting physical systems.

G. A. Kuzaev, T. A. Lebedeva

Richard Gebauer, Nick Karcher, Jonas Hurst +2 more

Superconducting circuits, as used for quantum computing experiments, are commonly interfaced by microwave pulse sequences with gigahertz frequencies. To generate and analyze these pulses, we developed a versatile FPGA-based electronics platform. The modular FPGA firmware guarantees highest accuracy on the nanosecond timescale. More complex data acquisition and control schemes utilize the real-time co-processor of the heterogeneous Multiprocessor System-on-Chip (MPSoC) through an application-specific framework called Taskrunner. The framework complements the FPGA logic with versatile and low-latent control, data aggregation and evaluation capabilities. Within the framework, user tasks are specified conveniently using standard C language and compiled on the fly directly on the MPSoC platform.In this paper, we present the architecture of our Taskrunner software framework. We also provide timing benchmarks and compare execution times of common quantum computing characterization experiments with an FPGA-only approach.