Camera

Full-Frame CCDs

Full-Frame CCDs Among charge-coupled devices, full-frame CCDs have the simplest architecture. The classical full-frame CCD design employs a single parallel register for photon exposure, charge integration, and charge transport. In order to control the exposure and block light from striking the CCD during the read process (which would otherwise result in charge smearing) a mechanical […]

Camera

Camera Sensitivity

Introduction The sensitivity of a camera is one of the most important aspects of camera performance – with inadequate sensitivity, your experiment may simply be impossible. However, sensitivity cannot be represented by one number or factor alone – while one camera may outperform another at one light level or exposure time, the situation may be […]

Camera

Signal to Noise Ratio

Signal-to-Noise Ratio Signal-to-noise ratio (SNR) describes the quality of a measurement. In CCD imaging, SNR refers to the relative magnitude of the signal compared to the uncertainty in that signal on a per-pixel basis. Specifically, it is the ratio of the measured signal to the overall measured noise (frame-to-frame) at that pixel. High SNR is […]

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Optical Trapping

Introduction Optical Trapping, also known as Optical Tweezers (OT), is a technique that uses light scattering to hold an object in place. OT is based on a concept outlined by Arthur Ashkin in 1986 that later earned him the Nobel Prize in Physics 2018. When a laser beam is directed at a particle, cell, or […]

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Fiberoptics

Fiberoptics In the majority of CCD applications, light reaches the CCD through a lens- or mirror-based optical system. However, in some situations it is advantageous to use an image-preserving fiberoptic bundle in place of conventional imaging optics. Significant gains in the amount of light collected can be achieved by directly coupling the light source to […]

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Intro To Electrophysiology

Introduction Electrophysiology is the study of electrical properties of biological cells and tissues, and can be broadly split into neural (nerves throughout the body, especially the spine and brain, also the retina) and cardiac (to do with the heart) electrophysiology. Electrophysiology is a vital tool in neuroscience, where the right tools can interrogate the activity […]

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Metachrome II Coating

Metachrome II Coating Metachrome II* is a composite phosphor coating developed by Teledyne Photometrics for use on its products to improve sensitivity of CCDs in blue-visible and ultraviolet (UV) wavelengths. The application of a thin coating of Metachrome II to the surface of a CCD effectively, reliably, and inexpensively achieves a dramatic increase in device […]

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Saturation and Blooming

Saturation and Blooming Saturation and blooming are phenomena that occur in all cameras and it can affect both their quantitative and qualitative imaging characteristics. If each individual pixel can be thought of as a well of electrons, then saturation refers to the condition where the well becomes filled. The amount of charge that can be […]

Camera

Resolution and Numerical Aperture

Introduction An often-asked question in imaging is whether two objects are in the same or separate places. Resolution, the ability to tell two nearby features apart, is a key parameter of microscope optics that becomes more challenging at smaller length scales. Yet, this has surprisingly little to do with the microscope’s ability to magnify. In […]