scholarly journals Different Single-Photon Response of Wide and Narrow Superconducting MoxSi1−x Strips

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Yu. P. Korneeva ◽  
N.N. Manova ◽  
I.N. Florya ◽  
M. Yu. Mikhailov ◽  
O.V. Dobrovolskiy ◽  
...  
Keyword(s):  
Single Photon ◽  
Single Photon Response

scholarly journals Nano-optical single-photon response mapping of waveguide integrated molybdenum silicide (MoSi) superconducting nanowires

2016 ◽  
Vol 24 (13) ◽  
pp. 13931 ◽  
Author(s):  
Jian Li ◽  
Robert A. Kirkwood ◽  
Luke J. Baker ◽  
David Bosworth ◽  
Kleanthis Erotokritou ◽  
...  
Keyword(s):  
Single Photon ◽  
Molybdenum Silicide ◽  
Superconducting Nanowires ◽  
Response Mapping ◽  
Single Photon Response

scholarly journals Diffusion of the Second Messengers in the Cytoplasm Acts as a Variability Suppressor of the Single Photon Response in Vertebrate Phototransduction

2008 ◽  
Vol 94 (9) ◽  
pp. 3363-3383 ◽  
Author(s):  
Paolo Bisegna ◽  
Giovanni Caruso ◽  
Daniele Andreucci ◽  
Lixin Shen ◽  
Vsevolod V. Gurevich ◽  
...  
Keyword(s):  
Single Photon ◽  
Second Messengers ◽  
Single Photon Response

scholarly journals Analytical Study of Front-End Circuits Coupled to Silicon Photomultipliers for Timing Performance Estimation under the Influence of Parasitic Components

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4428
Author(s):  
Pietro Antonio Paolo Calò ◽  
Savino Petrignani ◽  
Michele Di Gioia ◽  
Cristoforo Marzocca
Keyword(s):  
Single Photon ◽  
Performance Estimation ◽  
Laser Source ◽  
Detector Response ◽  
Silicon Photomultipliers ◽  
Parasitic Inductance ◽  
Front End ◽  
Single Photon Response ◽  
Variable Configuration ◽  
Definition Of

Full exploitation of the intrinsic fast timing capabilities of analog silicon photomultipliers (SiPMs) requires suitable front-end electronics. Even a parasitic inductance of a few nH, associated to the interconnections between the SiPM and the preamplifier, can significantly degrade the steepness of the detector response, thus compromising the timing accuracy. In this work, we propose a simple analytic expression for the single-photon response of a SiPM coupled to the front-end electronics, as a function of the main parameters of the detector and the preamplifier, taking into account the parasitic inductance. The model is useful to evaluate the influence of each parameter of the system on the slope of its response and to guide the designer in the definition of the architecture and the specifications for the front-end electronics. The results provided by the model have been successfully compared with experimental measurements from a front-end circuit with variable configuration based on a bipolar junction transistor (BJT), coupled to a 3 × 3 mm2 SiPM stimulated by a fast-pulsed laser source.

scholarly journals Method For Measuring Sub-Micron Facula At Single-Photon Level With Silicon Photomultiplier

2021 ◽  
Author(s):  
Yaxian Yang ◽  
Guoqing Zhang ◽  
Chen Zhang ◽  
Xinyue Cao ◽  
Lina Liu ◽  
...  
Keyword(s):  
Single Photon ◽  
Dimensional Space ◽  
Avalanche Photodiode ◽  
Objective Lens ◽  
Silicon Photomultiplier ◽  
Silicon Photomultipliers ◽  
Positioning Stage ◽  
Weak Light ◽  
Single Photon Response ◽  
Nominal Resolution

Abstract Sub-micron faculae (light spots) at the single-photon level have important applications in many fields. This report demonstrates a method for measuring facula size at the sub-micron single-photon level indirectly. The developed method utilizes Silicon Photomultipliers (SiPMs) as the single-photon response detectors, combined with a nano-positioning stage. The approach involves one- or two-dimensional space scanning and a deconvolution operation, which enable evaluations of the size and spatial distribution of focused facula in a single-photon-level pulsed laser. The results indicate that the average full width at half maximum of the faculae is about 0.66 µm, which is close to the nominal resolution of the objective lens of the microscope (0.42 µm). The proposed method has two key advantages: (1) it can measure sub-micron facula at the single-photon level, and (2) the sub-micron facula can easily be aligned with the detector because the array area of the avalanche photodiode cells in SiPM is usually larger than one square millimeter, and there is no need to put an optical slit, knife edge, or pinhole in front of the detector. The method described herein is applicable in weak light facula detection related fields.

scholarly journals Implications of dimeric activation of PDE6 for rod phototransduction

Open Biology ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 180076 ◽  
Author(s):  
Trevor D. Lamb ◽  
Martin Heck ◽  
Timothy W. Kraft
Keyword(s):  
Single Photon ◽  
Electrical Response ◽  
Hydrolytic Activity ◽  
Two Dimensional ◽  
Driving Function ◽  
Disc Membrane ◽  
Continuous Noise ◽  
Spontaneous Activation ◽  
Single Photon Response ◽  
Quantitative Explanation

We examine the implications of a recent report providing evidence that two transducins must bind to the rod phosphodiesterase to elicit significant hydrolytic activity. To predict the rod photoreceptor's electrical response, we use numerical simulation of the two-dimensional diffusional contact of interacting molecules at the surface of the disc membrane, and then we use the simulated PDE activity as the driving function for the downstream reaction cascade. The results account for a number of aspects of rod phototransduction that have previously been puzzling. For example, they explain the existence of a greater initial delay in rods than in cones. Furthermore, our analysis suggests that the ‘continuous’ noise recorded in rods in darkness is likely to arise from spontaneous activation of individual molecules of PDE at a rate of a few tens per second per rod, probably as a consequence of spontaneous activation of transducins at a rate of thousands per second per rod. Hence, the dimeric activation of PDE in rods provides immunity against spontaneous transducin activation, thereby reducing the continuous noise. Our analysis also provides a coherent quantitative explanation of the amplification underlying the single photon response. Overall, numerical analysis of the dimeric activation of PDE places rod phototransduction in a new light.

Optimization of Single-Photon Response Transmission at the Rod-to-Rod Bipolar Synapse

Physiology ◽  
2007 ◽  
Vol 22 (4) ◽  
pp. 279-286 ◽  
Author(s):  
Haruhisa Okawa ◽  
Alapakkam P. Sampath
Keyword(s):  
Light Absorption ◽  
Single Photon ◽  
Absolute Threshold ◽  
Bipolar Cells ◽  
Physiological Mechanisms ◽  
Rod Photoreceptors ◽  
Dim Light ◽  
Single Photon Response ◽  
Rod Bipolar Cells

Our ability to see in dim light is limited by the statistics of light absorption in rod photoreceptors and the faithful transmission of the light-evoked signals through the retina. This article reviews the physiological mechanisms at the synapse between rods and rod bipolar cells, the first relay in a pathway that mediates vision near absolute threshold.

scholarly journals Developmental regulation of calcium-dependent feedback in Xenopus rods

2004 ◽  
Vol 124 (5) ◽  
pp. 569-585 ◽  
Author(s):  
Eduardo Solessio ◽  
Shobana S. Mani ◽  
Nicolas Cuenca ◽  
Gustav A. Engbretson ◽  
Robert B. Barlow ◽  
...  
Keyword(s):  
Guanylate Cyclase ◽  
Single Photon ◽  
Developmental Regulation ◽  
Cutoff Frequency ◽  
Power Spectra ◽  
Recovery Phase ◽  
Calcium Dependent ◽  
Time To Peak ◽  
Single Photon Response ◽  
Phototransduction Pathway

The kinetics of activation and inactivation in the phototransduction pathway of developing Xenopus rods were studied. The gain of the activation steps in transduction (amplification) increased and photoresponses became more rapid as the rods matured from the larval to the adult stage. The time to peak was significantly shorter in adults (1.3 s) than tadpoles (2 s). Moreover, adult rods recovered twice as fast from saturating flashes than did larval rods without changes of the dominant time constant (2.5 s). Guanylate cyclase (GC) activity, determined using IBMX steps, increased in adult rods from ∼1.1 s−1 to 3.7 s−1 5 s after a saturating flash delivering 6,000 photoisomerizations. In larval rods, it increased from 1.8 s−1 to 4.0 s−1 9 s after an equivalent flash. However, the ratio of amplification to the measured dark phosphodiesterase activity was constant. Guanylate cyclase–activating protein (GCAP1) levels and normalized Na+/Ca2+, K+ exchanger currents were increased in adults compared with tadpoles. Together, these results are consistent with the acceleration of the recovery phase in adult rods via developmental regulation of calcium homeostasis. Despite these large changes, the single photon response amplitude was ∼0.6 pA throughout development. Reduction of calcium feedback with BAPTA increased adult single photon response amplitudes threefold and reduced its cutoff frequency to that observed with tadpole rods. Linear mathematical modeling suggests that calcium-dependent feedback can account for the observed differences in the power spectra of larval and adult rods. We conclude that larval Xenopus maximize sensitivity at the expense of slower response kinetics while adults maximize response kinetics at the expense of sensitivity.

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