Maximilian Sergio

A single photon avalanche diode array fabricated in 0.35-μm CMOS and based on an event-driven readout for TCSPC experiments

The design and characterization of an imaging sensor based on single photon avalanche diodes is presented. The sensor was fully integrated in a 0.35μm CMOS technology. The core of the imager is an array of 4x112 pixels that independently and simultaneously detect the arrival time of photons with picosecond accuracy. A novel event-driven readout scheme allows parallel column-wise and non-sequential, on-demand row-wise operation. Both time-correlated and time-uncorrelated measurements are supported in the sensor. The readout scheme is scalable and requires only 11 transistors per pixel with a pitch of 25μm. A number of standard performance measurements for the imager are presented in the paper. An average dark count rate of 6Hz and 750Hz are reported at room temperature respectively for an active area diameter of 4μm and 10μm, while the dead time is 40ns with negligible crosstalk. A timing resolution better than 80ps over the entire integrated array makes this technique ideal for a fully integrated high resolution streak camera, thus enabling fast TCSPC experiments. Applications requiring low noise, picosecond timing accuracies, and measurement parallelism are prime candidates for this technology. Examples of such applications include bioimaging at cellular and molecular level based on fluorescence lifetime imaging and/or, fluorescence correlation spectroscopy, as well as fast optical imaging, optical rangefinders, LIDAR, and low light level imagers.

A Single Photon Avalanche Diode Array Fabricated in Deep-Submicron CMOS Technology

We report the first fully integrated single photon avalanche diode array fabricated in 0.35 mum CMOS technology. At 25 mum, the pixel pitch achieved by this design is the smallest ever reported. Thanks to the level of miniaturization enabled by this design, we were able to build the largest single photon streak camera ever built in any technology, thus proving the scalability of the technology. Applications requiring low noise, high dynamic range, and/or picosecond timing accuracies are the prime candidates of this technology. Examples include bio-imaging at cellular and molecular level, fast optical imaging, single photon telecommunications, 3D cameras, optical rangefinders, LIDAR, and low light level imagers

A CMOS 64×48 Single Photon Avalanche Diode Array with Event-Driven Readout

This paper presents a CMOS array of 64times48 pixels capable of detecting single photons with timing accuracies better than 80ps. Upon photon arrival, a digital pulse is generated and routed by an event-driven digital readout scheme to a specific location for further processing. This method allows non-sequential row-wise and simultaneous column-wise detection while preserving photon arrival timing information. The readout scheme is scalable and it is shown to have minimal impact on timing accuracy. Time-correlated fluorescence spectroscopy and optical rangefinders are among the target applications for this technology

A Cmos Microsystem Combining Magnetic Actuation and In-Situ Optical Detection of Microparticles

We present a CMOS-based hybrid microfluidic system that combines the manipulation of magnetic microparticles through a magnetic field with in situ optical detection via single photon avalanche diodes (SPADs). Magnetic particles are actuated within a glass micro-capillary and are detected upon passage over the SPAD, where they block incident light and thus lower the photon count. The optical sensors, which are not influenced by the magnetic actuation forces, allow detecting the presence of magnetic particles of 30, 5 and 1 mum diameter, while being able to distinguish between different sizes.

Actuation and Detection of Magnetic Microparticles in a Bio- analytical Microsystem with Integrated CMOS Chip

In this chapter, we present a hybrid microsystem that combines magnetic actuation with in situ optical detection. The chosen detection mechanism allows the observation and measurement of single magnetic microparticles of different sizes, as well as the detection of fluorescent labels attached to the particles’ surface. We are able to detect mouse IgG as target antigen in a sandwich immunoassay down to a concentration of 0.1 ng/ml. Our work represents a first step toward a full diagnostic LOC system for detection of specific antigens.

A quantum imager for intensity correlated photons

We report on a device capable of imaging second-order spatio-temporal correlations g(2)(x, τ) between photons. The imager is based on a monolithic array of single-photon avalanche diodes (SPADs) implemented in CMOS technology and a simple algorithm to treat multiphoton time-of-arrival distributions from different SPAD pairs. It is capable of 80 ps temporal resolution with fluxes as low as 10 photons s−1 at room temperature. An important application might be the local imaging of g(2) as a means of confirming the presence of true Bose–Einstein macroscopic coherence (BEC) of cavity exciton polaritons.

An intra-chip electro-optical channel based on CMOS single photon detectors

A low-cost, high-density scalable technique is proposed for low bit rate intra-chip optical data communication. The data stream directly modulates a low-intensity photon flux that propagates through standard silicon layers. Single photon avalanche diodes simultaneously perform photon detection and data demodulation in a fraction of the area required by a pad. The method exploits only integrated CMOS components and requires no post-processing steps

On the application of a monolithic array for detecting intensity-correlated photons emitted by different source types.

It is not widely appreciated that many subtleties are involved in the accurate measurement of intensity-correlated photons; even for the original experiments of Hanbury Brown and Twiss (HBT). Using a monolithic 4 x 4 array of single-photon avalanche diodes (SPADs), together with an off-chip algorithm for processing streaming data, we investigate the difficulties of measuring second-order photon correlations g((2))(x(iota), t(iota),x, t) in a wide variety of light fields that exhibit dramatically different correlation statistics: a multimode He-Ne laser, an incoherent intensity-modulated lamp-light source and a thermal light source. Our off-chip algorithm treats multiple photon-arrivals at pixel-array pairs, in any observation interval, with photon fluxes limited by detector saturation, in such a way that a correctly normalized g((2)) function is guaranteed. The impact of detector background correlations between SPAD pixels and afterpulsing effects on second-order coherence measurements is discussed. These results demonstrate that our monolithic SPAD array enables access to effects that are otherwise impossible to measure with stand-alone detectors.