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Sub-Poisson statistics observed in an electronically shuttered and back-illuminated CCD pixel

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Published in:
IEEE Trans. Electron Devices, Vol. 44, No. 1, January 1997, pp. 69-73. Selected Papers on CCD and CMOS Imagers, SPIE Milestone Series, Vol. MS 177, 2003, pp. 169-173.

Summary

The variance versus average signal has been measured for a pixel in an electronically shuttered and back-illuminated CCD imaging array. The measurements demonstrate that, over a certain operating range, the electronic shutter modifies the input Poisson distributed photoelectrons during the collection process such that the charge signal accumulated in the CCD well has a sub-Poisson distribution (variance less than a mean). A simple one-dimensional model has been developed that explains the experimental results.
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Summary

The variance versus average signal has been measured for a pixel in an electronically shuttered and back-illuminated CCD imaging array. The measurements demonstrate that, over a certain operating range, the electronic shutter modifies the input Poisson distributed photoelectrons during the collection process such that the charge signal accumulated in the...

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CW operation of monolithic arrays of surface-emitting AlGaAs diode lasers with dry-etched vertical facets and parabolic deflecting mirrors

Summary

A monolithic two-dimensional array of surface-emitting AlGaAs diode lasers with dry-etched vertical facets and parabolic deflecting mirrors was mounted junction-side up on a W / Cu microchannel heatsink and evaluated under continuous-wave (CW) operating conditions. Both the facets and parabolic deflecting mirrors were etched using chlorine ion-beam-assistd etching. Threshold current densities of different sections of the array were consistently around 240 A/cm (to the second power), and measured CW differential quantum efficiencies were in the 46-48% range. CW power densities as high as 148 W/cm (to the second power) were achieved with an average temperature rise of less than 25 degrees C in this junction-side-up configuration.
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Summary

A monolithic two-dimensional array of surface-emitting AlGaAs diode lasers with dry-etched vertical facets and parabolic deflecting mirrors was mounted junction-side up on a W / Cu microchannel heatsink and evaluated under continuous-wave (CW) operating conditions. Both the facets and parabolic deflecting mirrors were etched using chlorine ion-beam-assistd etching. Threshold current...

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Dynamic suppression of interface-state dark current in buried-channel CCDs

Published in:
IEEE Trans. Electron. Devices, Vol. 38, No. 2, February 1991, pp. 285-290.

Summary

It is shown that the time dependence of the carrier generation rate at a depleted surface can be exploited to completely suppress interface-state dark current in buried-channel charge-coupled devices (CCDs). When a surface is switched from an inverted to a depleted state, the generation current recovers with a time constant which is strongly temperature dependent and varies from a few milliseconds at room temperature to nearly 3 h at -80 degrees C. This property can be applied to three- and four-phase CCDs by exchanging charge packets between adjacent phases within a cell at a rate that ensures that each phase remains out of inversion for time that is short in comparison to the recovery time. Measurements of this effect have been made on a CCD imager over the temperature range from -40 degrees C to +22 degrees C, and the results agree well with theory.
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Summary

It is shown that the time dependence of the carrier generation rate at a depleted surface can be exploited to completely suppress interface-state dark current in buried-channel charge-coupled devices (CCDs). When a surface is switched from an inverted to a depleted state, the generation current recovers with a time constant...

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