Massachusetts Institute of Technology

Brian F Aull

Robert K Reich

Bernard B Kosicki

Daniel R Schuette

David C Shaver

Dennis D Rathman

Matthew J Renzi

Christopher W Leitz

William D Goodhue

Steven W Rabe

Kirby B Nichols

Alvin Gabriel Stern

David Volfson

Andrew H Loomis

Kevin Ryu

T C Sollner

Renee D Lambert

Bradley J Felton

Joseph S Ciampi

Karl Alexander McIntosh

Douglas J Young

A chip-to-chip integration process for rapid prototyping of silicon avalanche photodiode (APD) arrays has been developed. This process has several advantages over wafer-level 3D integration, including: (1) reduced cost per development cycle since a dedicated full-wafer read-out integrated circuit (ROIC) fabrication is not needed, (2) compatibility with ROICs made in previous fabrication runs, and (3) accelerated schedule. The process provides several advantages over previous processes for chip-to-chip integration, including: (1) shorter processing time as the chips can be diced, bump-bonded, and then thinned at the chip-level faster than in a wafer-level back-illumination process, and (2) the CMOS substrate provides mechanical support for the APD device, allowing integration of fast microlenses directly on the APD back surface. This approach yields APDs with low dark count rates (DCRs) and higher radiation tolerance for harsh environments and can be extended to large arrays of APDs.

Rapid prototyping of single-photon-sensitive silicon avalanche photodiodes

Embodiments of the present invention include an electron counter with a charge-coupled device (CCD) register configured to transfer electrons to a Geiger-mode avalanche diode (GM-AD) array operably coupled to the output of the CCD register. At high charge levels, a nondestructive amplifier senses the charge at the CCD register output to provide an analog indication of the charge. At low charge levels, noiseless charge splitters or meters divide the charge into single-electron packets, each of which is detected by a GM-AD that provides a digital output indicating whether an electron is present. Example electron counters are particularly well suited for counting photoelectrons generated by large-format, high-speed imaging arrays because they operate with high dynamic range and high sensitivity. As a result, they can be used to image scenes over a wide range of light levels.

Single-electron detection method and apparatus for solid-state intensity image sensors with a charge splitting device

Embodiments of the present invention include complementary metal-oxide-semiconductor (CMOS) readout architectures for photon-counting arrays with a photon-counting detector, a digital counter, and an overflow bit in each of the sensing elements in the array. Typically, the photon-counting detector is a Geiger-mode avalanche photodiode (APD) that emits brief pulses every time it detects a photon. The pulse increments the digital counters, which, in turn, sets the overflow bit once it reaches a given count. A rolling readout system operably coupled to each sensing element polls the overflow bit, and, if the overflow bit is high, initiates a data transfer from the overflow bit to a frame store. Compared to other photo-counting imagers, photon-counting imagers with counters and overflow bits operate with decreased transfer bandwidth, high dynamic range, and fine spatial resolution.

CMOS readout architecture and method for photon-counting arrays

Single-electron detection method and apparatus for solid-state intensity image sensors with a charge-metering device

A photodiode is provided by the invention, including an n-type active region and a p-type active region. A first one of the n-type and p-type active regions is disposed in a semiconductor substrate at a first substrate surface. A second one of the n-type and p-type active regions includes a high-field zone disposed beneath the first one of the active regions at a first depth in the substrate, a mid-field zone disposed laterally outward of the first active region at a second depth in the substrate greater than the first depth, and a step zone connecting the high-field zone and the mid-field zone in the substrate.

High fill-factor avalanche photodiode

A photon-counting Geiger-mode avalanche photodiode intensity imaging array includes an array of pixels, each having an avalanche photodiode. A pixel senses an avalanche event and stores, in response to the sensed avalanche event, a single bit digital value therein. An array of accumulators are provided such that each accumulator is associated with a pixel. A row decoder circuit addresses a pixel row within the array of pixels. A bit sensing circuit converts a precharged capacitance into a digital value during read operations.

Digital photon-counting geiger-mode avalanche photodiode solid-state monolithic intensity imaging focal-plane with scalable readout circuitry

An electrooptical switch for modulating a bias light beam in response to a control beam. The switch includes a modulator for modulating the bias beam to produce an output light beam therefrom, the modulator having a variable transmissivity; a detector module for receiving the control beam and generating a control signal therefrom, the detector module exhibiting switching operation in response to the control beam; and an amplifier for amplifiying the control signal to modulate the transmissivity of the modulator.

Electrooptical switch with separate detector and modulator modules

An electro-optical device for providing spatial modulation of an incoming electromagnetic wave signal, and preferably a two-dimensional incoming signal applied orthogonally to an input plane of the device, which device includes an array of modulation regions for providing such modulation of portions of the incoming signal. An array of first reflective mirrors are positioned so as to direct the incoming electromagnetic wave signal portions through the interaction layer regions of the modulation regions in a direction substantially parallel thereto and an array of second reflective mirrors directs the modulated electromagnetic wave signal portions outwardly from the device to provide a two-dimensional spatially modulated output electromagnetic wave signal.

Spatial light modulator

Growing community of inventors

Cambridge, MA, United States of America

Brian F Aull