Recent advances in single-shot detection in ultrafast spectroscopies have dramatically expanded the applicability of nonlinear and multi-dimensional ultrafast spectroscopies to previously unexplored regions of the spectrum as well as to novel dynamical and physical and chemical processes. Unlike traditional pump-probe detection schemes, where the pump-probe time delay is obtained using mechanical delay stages, single-shot detected experiments employ a mechanism where dynamical information about a process in a sample may be captured with femtosecond time-resolution for the entire duration of the event, (up to ten’s of picoseconds), and read out within a single-shot. The benefits of single-shot detection include up to orders of magnitude reduction in experimental acquisition times, the potential to measure irreversible processes, and the ability to reduce unwanted nonlinear effects by using modest pump excitation energies. We discuss the performance characteristics of modern scientific Complementary Metal Oxide Semiconductor (sCMOS) cameras that make them well-suited detectors for these experiments; a highly parallel pixel readout mechanism resulting in fast frame rates with low read noise, high quantum efficiency for optical detection, excellent linearity, high dynamic range and flexible pixel binning. Recent experiments implementing sCMOS technology for this detection scheme, such as single-shot detected nonlinear Terahertz Kerr Effect (TKE) spectroscopy and broadband Single-Shot Transient Absorption spectroscopy (SSTA), are reviewed.
Raman spectroscopy is an analytical technique that non-invasively provides “chemical fingerprinting” information with high degree of specificity and sensitivity for medical/biological diagnostics. However, to avoid autofluorescence background signals, the measurements need to be carried out in the Near Infrared (NIR), where Raman scattering efficiency is low (proportional to λlaser-4). This provides challenges in terms of both detection sensitivity and minimisation of diagnostics time. Traditional high NIR sensitivity Si-based detectors suffer from elevated dark current, which can be minimised through cooling, but at the expense of a competing blue-shifting of sensor Quantum Efficiency (QE). Low Dark Current Deep-Depletion (LDC-DD) CCD technology first introduced by Andor minimises the need for deep-cooling, preserving QE for maximum detection capability and achieving higher signal-to-noise more quickly. The origins of this limitation of Si-based sensors and Andor’s technical solution will be explored. Additionally, the configurability of Andor’s spectrographs for researchers designing custom-built Raman and/or multi-diagnostics spectroscopy systems will be discussed. This instrumentation can facilitate new experiments which were not previously possible to enable new scientific breakthroughs. Higher selectivity, sensitivity, and rapidness of data acquisition offers faster sample screening, better clinical diagnostic measurements and minimisation of patient discomfort.
The Next Generation Transit Survey (NGTS) has now been operating for six years, discovering and characterizing transiting exoplanets around bright stars. We outline the NGTS project, including the Andor CCD cameras used to perform high-precision time-series photometry. We quantify the photometric precision for a sample of over 20,000 bright star observations. We find for single NGTS telescope observations we achieve a 30-minute photometric precision of 400 ppm at low airmass. This is in good agreement with the photometric noise predicted using a four-component noise model. We find that the photometric noise for bright stars (G < 12) is dominated by atmospheric scintillation. We also present details of the NGTS multi-telescope observing mode, whereby 12 telescopes can be used simultaneously on a single target star to achieve a 30-minute photometric precision of 100 ppm. Finally, we describe a new generation scientific CMOS camera that we will be testing on-sky at the NGTS facility to determine if it can compete with state-of-the-art CCD cameras used for high precision bright star photometry.
The advent of rapid, cost-effective, high-powered lasers are driving forward advancements in the fields of for soft X-ray and EUV imaging, ptychography, spectroscopy and tomography. This coupled with increasing investment in industrial EUV lithography and semiconductor metrology processes is creating demand for fast, high resolution and sensitive detectors in the 20 eV to 10 keV range. Here we present the latest detector developments in the field of sCMOS for direct EUV and soft X-ray detection. We demonstrate how sCMOS technology is able to overcome the limitations of slow scan CCD technology to provide high resolution direct EUV and soft X-ray detection with a greater than 16-fold speed increase whilst maintaining low noise compared to classical CCD detectors.
Leaders development and manufacture of high performance scientific digital cameras and spectrographs from hard X-ray to SWIR for academic, industrial and government applications.
Leaders development and manufacture of high performance scientific digital cameras and spectrographs from hard X-ray to SWIR for academic, industrial and government applications
Novel and commercially-relevant applications for soft X-Ray (SXR) methods - protein structural characterization, tomography, and chemical detection - are driving a demand for fast and sensitive detectors in the 20 eV to 10 keV range, often with unusual geometries to accommodate placement in beam lines and vacuum chambers. Here we present several novel CCD SXR detector solutions with high quantum efficiency and readout speed, and where the design can be modified to tilt, tile or extend the sensor from the camera body. Each of these implementations have provided quantum efficiencies peaked at 95% in the soft X-Ray regime. These CCDs while providing very high sensitivity are however generally limited to slow readout rates of ~ 1 Hz for the full frame. Scientific CMOS sensor technology can provide much faster frame rates, large field-of-view and lower readnoise floors. Here we also discuss our sCMOS based solutions for indirect hard X-Ray Detection.
The manner in which polymer chains pack and organize in thin film structures is crucial to maximizing the efficiency of
charge and energy transport processes in solar cell devices. We use new spectroscopic and electrical imaging tools to
spatially map and correlate local structure (chain conformation, packing, morphology) to local photocurrent generation
efficiency. Both Raman and photoluminescence approaches are used that provide unique insights into important
structural attributes and how they vary with film morphology. Simultaneous electrical measurements are then used to establish the roles of specific structural features to photocurrent production.
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