2018 1st International SPAD Sensor Workshop (ISSW)imagesensors.org/wp-content/uploads/2019/05/ISSW-Booklet... · 2019. 5. 29. · SiPM and SPAD Arrays for Next Generation LiDAR Carl

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20181stInternationalSPADSensorWorkshop(ISSW)

February26th–28th,2018LesDiablerets,Switzerland

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Sponsors

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TheInternationalSPADSensorWorkshopfocusesonthestudy,modeling,design,fabrication and characterization of SPAD sensors. The workshop welcomes allresearchers,practitionersandeducators interestedinSPADs,SPADimagers,andassociatedapplications,notonlyinimagingbutalsoinotherfields.The first edition of the workshopwill gather experts in all areas of SPADs andSPADrelatedapplications in theSwissAlps,whereover20 invited speakerswillanimate three days of study, information dissemination and debates. Genuinealpineactivitieswillcompletetheevent,everythinginaspectacularsetting.TheworkshopissupportedbytheInternationalImageSensorSociety(IISS).SteeringCommittee

SaraPellegrini,STMicroelectronics,UnitedKingdom

RobertKHenderson,EdinburghUniversity,UnitedKingdom

DavidStoppa,AMS,Switzerland

AlbertoTosi,PolitecnicodiMilano,Italy

EdoardoCharbon,EPFLAQUA,Switzerland

ClaudioBruschini,EPFLAQUA,SwitzerlandLocalOrganization

ISSW 2018 is organized by the Advanced Quantum Architecture Laboratory(AQUA)oftheÉcolePolytechniqueFédéraledeLausanne(EPFL).TheAQUAlaboratoryisbasedinNeuchâtelSwitzerland.Itsresearchmissionistomodel and develop hardware/software systems based on quantum devices.Particular emphasis is on high-speed 2D/3D optical sensing, embedded andreconfigurableprocessingarchitectures, singlephotonavalanchedevices (SPAD)anddesignoptimizationtechniques.Website:http://aqua.epfl.ch/Venue

Les Diablerets is a village and ski resort located in themunicipality of Ormont-DessusinthecantonofVaud,Switzerland.Thevillageliesatanaltitudeof1,160metresonthenorthsideofthemassifoftheDiablerets intheSwissAlps. ItcanbeaccessedbytrainorbyroadfromAigle.LesDiablerets,isanimportantcentreforadventuresports.Eveninsummer,theGlacier 3000 ski region in the heart of the Vaud Alps offers skiing and glacierenjoyment.Theworkshopwill takeplaceatEurotelVictoria,CheminduVernex3, 1865 LesDiablerets.

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Program―Monday,February26th―DEVICES

Time Event

12:00–13:00 Registration

13:00–13:30 WelcomeSpeechEdoardoCharbon,EPFL

13:30–14:15 NIRSPADsandFast-gatingCircuitsAlbertoTosi,PolitecnicodiMilano

14:15–15:00IndustrialisedSPADsinDeep-submicronCMOS

TechnologySaraPellegrini,STMicroelectronics

15:00–15:45 IndustrializedNIRSPADTechnologyin180nmAmosFenigstein,TowerJazz

15:45–16:15 Coffeebreak

16:15–17:00 NUV-HDandNIR-HDSiPMsandApplicationsAlbertoGola,FondazioneBrunoKessler

17:00–17:45 SiPMandSPADArraysforNextGenerationLiDARCarlJackson,SensL

17:45–18:30Geiger-modeLiDARwithInP-basedSPADs:From

AirbornePlatformstoDriverlessCarsMarkItzler,ArgoAI

18:30–20:00 Welcomeaperoanddinner

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Program―Tuesday,February27th―ARCHITECTURES

Time Event

08:00–08:45 SPADsforFLIMRobertHenderson,UniversityofEdinburgh

08:45–09:30 FromSPADstoQuantumComputingEdoardoCharbon,EPFL

09:30–10:15 Multizone,MultiobjectD-TOFSystemin55nmRobertKappel,amsAG

10:00–10:30 Coffeebreak

10:30–11:15TheLatestonSPADImaginginJapan

-EventDetectionandQuickReadoutSchemes-KunihiroAsada,UniversityofTokyo

11:15–12:00OpticalSolutionsforLightIntensityEnhancementin

Large-PixelSizeSPADSensorsKenWu,VisEraTechnologiesCompany

12:00–13:30 Lunch

13:30–14:15 AngleSensitiveSPADsAlyoshaMolnar,CornellUniversity

14:15–15:00

ASPAD-based,DirectTimeofFlight,64Zone,15fps,ParallelRangingDeviceBasedon40nmCMOSSPAD

TechnologyBruceRaeandPascalMellot,STMicroelectronics

15:00–15:45 SPADBasedStreakCamerasWilfriedUhring,UniversityofStrasbourg

15:45–16:15 Coffeebreak

16:15–17:00 SpaceSecureCommunicationsusingSinglePhotonsPaoloVilloresi,UniversityofPadova

17:00–17:45

BCDSPADImagerwithReconfigurableMacropixelsforPhotonCounting,TimingandCoincidence

DetectionFedericaVilla,PolitecnicodiMilano

18:00–20:00 Nightwalk(uponregistration)

Curling(uponregistration)

20:00 Fondue-ChaletdesSources

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Program―Wednesday,February28th―APPLICATIONS

Time Event

08:45–09:30 ComputationalSingle-photonImagingGordonWetzstein,StanfordUniversity

09:30–10:15 ImagingattheSpeedofLightDanieleFaccio,UniversityofGlasgow

10:00–10:30 Coffeebreak

10:30–11:15SPADArrays:fromSingle-MoleculeDetectiontoWide-

FieldPhasorFluorescenceLifetimeImagingXavierMichalet,UCLA

11:15–12:00 LIDARsforAutomotiveandIndustrialApplicationsLucioCarrara,Fastree3D

12:00–12:45 Time-DomainNearInfraredSpectroscopyDavideContini,PolitecnicodiMilano

12:45–13:30 ImagingwithEntangledPhotonsMatteoPerenzoni,FondazioneBrunoKessler

12:00–13:30 Sandwichlunch(overlapswithpreviouspresentations)

14:15–16:15 Sledging(uponregistration)

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DEVICES

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NIRSPADsandFast-gatingCircuits

AlbertoTosi

PolitecnicodiMilano–DipartimentodiElettronica,InformazioneeBioingegneria

InGaAs/InP Single-Photon Avalanche Diodes (SPADs) are the best choice forpractical and reliable systems with high detection performance in the near-infrared wavelength range (1 µm - 1.7 µm). Recently, we developed planarInGaAs/InPSPADswithgoodperformanceintermsofphotondetectionefficiency(>30%),dark-countrate(fewkcps)andtimingjitter(<70ps).Themainlimitationto the count rate is still afterpulsing, which can be limited by reducing theavalanche charge with short gates (few hundreds of ps). To this aim, wedeveloped two fast-gating circuits for InGaAs/InP SPADs. The first one is asinusoidal gating system based on the SPAD-dummy approach, withprogrammable gate frequency from 900 to 1400MHz for synchronization withanyexternal lasersystems.Whenthesystemisrunningat1.3GHz,weachievedvery low afterpulsing (~ 1.5%), high count rate (650 Mcount/s), high photondetectionefficiency(>30%at1550nm), lowdarkcountrate(2.2·10-5pergate)and low timing jitter (<70ps FWHM). The secondapproach is basedona SiGeintegrated circuit (ASIC) for sub-nanosecond gating with < 300 ps rising/fallingedgesand low(<20ps)time jitter.SuchASICenablesthedevelopmentofhigh-performancecompactmodulesandarrays.

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IndustrialisedSPADsinDeep-submicronCMOSTechnology

SaraPellegrini

STMicroelectronics

WepresentSTMicroelectronics’firstfullyindustrialisedSPADdeviceinadvanced40 nm technology. The advantages of integrating such a devices within anintrinsically digital technology are presented. STM succeed in integratingdedicatedmicrolensontopofSPADspushingoverallpixelfillfactortoinexcessof70%. Thanks to junction engineering, a low DCR median of 50cps at roomtemperatureandahighPDPof5%at840nmisreported,whilemaintainingaVBDof only 15V. This enables a fully integrated chip with on chip high voltagegeneration and significant digital processing tobe realised for use in small areaTime-of-Flightproductssuitableformobileapplication.STM’s40nmtechnologyisautomotive grade, making it suitable for a wider range of application beyondconsumers.By taking advantage of the small digital node, a larger amount of logic can beintegrated inside the pixel, which is ready to be ported to a 3D stackedtechnology, where the logic can implemented in a fully digital dedicated layer,givingfreedomtohaveafullydedicatedtechnologyforthetoptierSPAD.

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IndustrializedNIRSPADTechnologyin180nm

AmosFenigstein1,TomerLeitner1,AlexKatz2,AviShoham2,YaelNemirovsky2

1. TowerJazz,MigdalHaemek,Israel2. Technion,IsraelInstituteofTechnology,Haifa,Israel

ThoughSPADs,andSiliconSPADsinparticular,havebeenaroundformanyyears,exciting device engineers’ imagination, they were rarely seen in commercialapplications.However,inrecentyearsSPADsaregettingalotofattentioninthefast growing applications and markets of Time of Flight (ToF) and 3D imaging.Applications vary from gaming and gesture control to automotive,wheremanyLiDARsystemsuseSPADastheirsensor.Thecombinationofsensitivitydowntovery few photons with excellent time resolution makes the SPAD a superiorsolution for such applications. The ToF applications use near Infrared (NIR)wavelengthsoasnottoannoyviewers’eye.Therefore,SPADsshouldbedesignedtooperatewellintheNIR.DuetotheNIR’sabsorptiondeepintheSi,theSPAD’sneed tobe“deepSPAD”, sometimescalled“bulk isolated”SPADs.Thismakes itharder to build fast quenching circuits which need access to both the SPAD’scathode and anode. Tower developed two kinds of SPADs: one is a “shallow”SPADwithaccess tobothanodeand cathode, andadeepSPADwithenhancedNIRsensitivity.BoththeSPADsareembeddedintoawell-established0.18µmCIStechnology platform. This enables having all the required analog and digitalcircuitry on the same chip, and in addition, a fully optimized CIS pinned photodiodepixel.BothkindsofSPADswillbedescribedalongwith theirperformanceparameters. For the “two sided” SPAD a specific novel application will bepresented. For thedeepSPADwewill present theoptimization steps (electricalandoptical)andtheenablingprocessmodifications,includingveryhighresistanceresistors for compact quenching circuit and elevated large micro-lenses foroptimized optics. This, of course, in addition to the SPAD diode optimization.Possible novel in-pixel circuitry will be discussed and Roadmap for furtherdevelopmentactivities.

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NUV-HDandNIR-HDSiPMsandApplications

AlbertoGola

FondazioneBrunoKessler(FBK),CenterforMaterialsandMicrosystems,Trento,Italy

Different SiPM technologies have been developed at FBK (Trento, Italy) fordifferentapplications.NearUltraviolet,HighDensity(NUV-HD)SiPMtechnology,based on a p-on-n junction, features peak photon detection efficiency (PDE) of65%at410nm,DarkCountRate (DCR) in theorderof50kHz/mm2, correlatednoiseof10%at55%PDE.Sensitivityremainshighdownto320nm,withaPDEof48%(inpackage).SinglePhotonTimingResolution(SPTR)isbelow30psFWHM,whenmeasuredonsingleSPADwithcoverededges,and75psFWHMforSiPMswith active areas of 1x1 mm2. NUV-HD SiPMs provide state-of-the art 85 psFWHM coincidence resolving time (CRT) in PET applications, when used toreadout the lightofaCaco-dopedLYSOcrystal.The low-electric-fieldvariantofthe NUV-HD technology (NUV-HD-LF) was optimized to operate at cryogenictemperaturesandfeaturesaDCRofafewmHz/mm2at77K.Atthistemperature,few-photon counting capability was demonstrated using a 24 cm2 SiPM arraycoupled toa singleanalog readout channel: themeasuredS/Nwas13.8on thesingle photon peak. Ongoing optimizations include the development of deviceswithextendeddeep-UVsensitivity:preliminaryresultsshowaPDEof20%at178nm. Focusingon the improvementof sensitivity at longerwavelengths, FBKhasrecently developed a NIR-HD SiPM technology, using an n-on-p junction and athickerepitaxiallayer.Thankstothetuningoftheelectricfieldforbetterchargecollection,recentresultsshowaPDEof20%at850nmand13.5%at900nmwith25µmcellpitchat10Vexcessbias.

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SiPMandSPADArraysforNextGenerationLiDAR

CarlJackson

SensL

Long distance LiDAR systems require high sensitivity to detect theweak returnlaser echos from low reflective objects. Silicon photomultipliers (SiPM) enablesingle-photon sensitivity thanks to the Geiger mode operation which provideshigh timing accuracy and high internal gain that overcomes the amplificationnoise limitation of external amplifiers for typical linear photodiodes (PIN andADP).ThenextgenerationLiDARsystemsmust satisfy the industry requirementfor staring LiDAR receivers. To preserve the long distance performance, a highpixelization of compact SiPM receivers is required. Alternatively, SPAD arraysprovide single-photon sensitivity together with a high pixelization, fast readoutandlownoise.SensLwillpresentsolutionsforhighsensitivityandlownoiseSiPMandSPADarraybasedLiDARreceivers fora largevarietyofapplicationssuchasoutdoorshighrateautomotiveLiDARsystems.

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Geiger-modeLiDARwithInP-basedSPADs:FromAirbornePlatformstoDriverlessCars

MarkItzler

ArgoAI

Theoperationofavalanchephotodiodes inGeigermodeprovides single-photondetection with excellent timing accuracy on a scalable semiconductor deviceplatform. For detection in the shortwave infrared (SWIR) region of the opticalspectrum, single-photon avalanche diodes (SPADs) based on the InGaAs/InPmaterialssystemanddesignedtooperateinGeigermodehavebeguntomatureover the past decade. Discrete SWIR SPAD detectors have enabled significantadvances in quantum communications in optical fiber, and arrays of thesedetectorshavebeencentraltothedevelopmentofsingle-photonimagingintheSWIRband. Inparticular, theuseof InP-basedarraysofGeiger-modedetectorsforlightdetectionandranging(LiDAR)fromairborneplatformsenablesthehigh-ratecollectionof3Dpointcloudimageryfromextremelylong(>10km)stand-offdistances and has resulted in order-of-magnitude increases in performancemetricssuchasareacoveragerateand3D imageresolution.Morerecently,wehave appliedGeiger-mode technology to shorter range LiDAR systemsdesignedfor automotive applications. The combination of two factors—single-photonsensitivityandthegreatereye-safetyoflasersatwavelengthsbeyond1400nm—providesdisruptiveautomotiveLiDARperformancethatwillbeessentialtofutureautonomousvehiclenavigation.

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ARCHITECTURES

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SPADsforFLIM

RobertK.Henderson

UniversityofEdinburgh

This talkwill comparethreerecentSPAD imagersaimingtoprovidecompetitiveperformance levels with other scientific imagers such as EMCCD or sCMOSsensors.Thethreecasesare(1)a256x256,100kfps,61%fill-factor16µmpitchbinaryimagesensor(2)a320x24020kfpsmicrolensed50%effectivefill-factor,8µm pixel pitch analogue photon counting imager (3) a 128x128, 45% fill-factor,500fps digital photon counting imager. Imaging exampleswill demonstrate thatthe fast frame, noiseless frame summation and picosecond time resolutionextendthecapabilitiesofexistingsensorsenablingparticletracking,fluorescencelifetime imagingandsuperresolution localization imaging.Newframeboundary-free image processing approaches such the smart aggregation technique andmotion distortion correction become possible with the oversampled read-noiseless data from these cameras. Despite around 4x less sensitivity to anEMCCD camera we are able to obtain a modest improvement in dSTORMlocalisation precision, indicating the promise of the technology. Scanning time-resolvedmicroscopyapproacheswillthenbepresentedemployingcomplexSPADpixels with time to digital converters. The 32x32 pixel MegaFrame sensor hasbeenembeddedinamulti-beamtwo-photonmicroscopeallowingfewframepersecondFRET/FLIMz-sectioningoflivecells.Finally,anew1024x8histogramminglinesensorisbeingappliedtoscanningin-vivoFLIMdeliveringvideoratelifetimeimagesovermulticoreoptical fibre ina lungendoscopysystem.ThenewsensorcandeliverspectrallyresolvedFLIMaswellastime-resolvedRamandatausingahistogramtimezoomingfeature.

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FromSPADstoQuantumComputing

EdoardoCharbon

EPFL

CMOSSPADshaveappearedin2003andsoonhaverisentothestatusof imagesensors with the creation of deep-submicron SPAD technology. The format ofthese imagesensorshasexpanded from8x4pixelsofour first LIDAR in2004 to512x512 pixels of recent time-resolved cameras, and the applications haveliterally exploded in the last three years, with the introduction of proximitysensingandportabletelemeters.ThecurrentpromiseisthatSPADbasedsensorswill be in every smartphone by 2018 and in every car by 2022. But SPADtechnologywasbornforscientificapplicationsandinscientificapplicationsitwillcontinue to innovate. For instance, super-resolution microscopy has alreadybenefittedfromSPADimagersandthistrendisexpectedtocontinuewell inthenext decade. In addition, other time-resolved techniques, such as time-of-flightPET, NIROT, FLIM, FRET, useful in many biomedical imaging modalities, willbecome more and more accurate and less and less expensive thanks to thescalabilityofCMOStechnologies.Withthe introductionofSPADs in3DCMOSICtechnologies in 2014, SPAD based imagers will be more compact, while at thesame timemoreadvanced techniquesand functionalitieswill beavailable.Veryrecently,SPADshavebeenproposedasaninterfacetoquantumprocessors,dueto their sensitivity and the capability of operating normally at cryogenictemperatures. The talkwill concludewitha technical andeconomicperspectiveonSPADsandSPADimagers,andavisionforSPADsandothercryo-CMOScircuitsinquantumcomputing.

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Multizone,MultiobjectD-TOFSystemin55nm

RobertKappel

amsAG

Direct Time-of-Flight (D-TOF) becomes more and more important for manyfunctionsinsmartphones,suchasproximitydetection,autofocusassist,gestureorpresencedetectionasthistechnologyenablescompactdeviceswithlowpowerconsumption.ThispresentationwillshowthesystemarchitectureoftheamsD-TOFtechnologyformobiledevicesandprovidesinsights intothemost importantblocks,suchasVCSELdriver,SPADwithquencher,thedual-inputTDCandhistogrammemory.The module is based on TSMC 55nmHV technology and contains sensor,processor and laser driver on a monolithic die, as well as a multi-mesa VCSELwithinthemodule.AcustomdevelopedSingle-Photon-Avalanche-Diodeandthecorresponding sensor array enable multi-zone andmulti-object detection usinghistogrambaseddatacollection.Theavailabilityoftherawhistogramdataallowsmulti-objectdetectionandmakesthesysteminsensitivetocrosstalkandsmudgeon the sensor. Distance resolution in themm-range is achieved by using a freerunningringoscillatorbasedTime-to-Digitalconverterwithdigitalcalibration.Ontheemitterside,theon-chipVCSELdriverpulsesamulti-emitterVCSELwithhighopticalpeakpowerandsub-nspulsewidthwhichresultsinanimprovedSNRandallows distinction ofmultiple objects at close distance to eachotherwithin theobservedscene.Thecompletesystemisclass1eyesafe.The system detects a white card (90%) at a distance up to 3m under incidentofficelightconditions.Measurementresultsshowingdistanceaccuracy,immunityto smudge, operation under sunlight and multi-object test cases, such asaccuratelydetectinganobjectbehindglasswillbepresented.

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TheLatestonSPADImaginginJapan-EventDetectionandQuickReadoutSchemes-

KunihiroAsadaandXiaoYang

VLSIDesignandEducationCenter,UniversityofTokyo

Though the SPAD is a high sensitive photon detector, an array of SPAD as animager is not always advantageous in terms of S/N ratio comparedwith linearCMOS imagers, since both the SPAD and linear imagers are suffering from thesamethermalnoises.SPADimagerscanmainlyshowtheiradvantageousfeaturefor capturing high speed events in photon detection at low photon densities,makinguseofthehighregenerativenon-linear gain feature. In this presentation we will show design of 2-D SPADimagerswithquickreadoutcircuits,whichcanselectivelyreadoutpixelsactivatedby incidentphotons. It isdesignedusinga rowparallelarchitecture, soas tobeespecially suited for detecting photon events intermittent in time and local inspace. A statistical thermal noise filtering mechanism is also included in thehardware to eliminate unnecessary readout of pixels activated by the thermalnoise.We implemented the SPAD imagers using a standard CMOS of 0.18 µmtechnology. Some experimental results will be also reported for demonstratingthe SPAD characteristics based on the standard CMOS technology andperformanceoftherowparallelSPADarchitectures.

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OpticalSolutionsforLightIntensityEnhancementinLarge-PixelSizeSPADSensors

Sheng-ChuanCheng,Chin-HanLin,Kuo-FengLin,KenWu,JCHsieh.

VisEraTechnologiesCompany,No12,DusingRd.1,HsinchuSciencePark,Taiwan(30078)

Near-infrared (NIR) imaging applicationof time-of-light (TOF) ismore andmorepopular.Single-photonavalanchediodes(SPAD)havebeenutilizedinavarietyofapplications that acquire time-of-flight system information in addition to lightintensity.However,complexelectronicslayoutlimitedPhotodioedareaandthencause bad NIR collection efficienence. To solve this problem, we proposed aopticalsolution(Planarlenswithbinarylevel)toconcentrateincominglightinourpreviousstudy.Thefinite-differencetime-domainmethodisusedtosimulatetheoptimizationof thenewstructuraldevelopment,particularly the focus lengthtophotodiodes, lens height, and refractive index of the lens. The effects of focusheight, lensheight,and refractive indexof lensare subsequentlydescribed.WealsodemonstratedanefficientopticaldesignandrelatedprocesstoenhanceNIRcollectionefficiencyinlargepixelsizeSPADsensorsuccessfully.Baseonpreviousexperience,wecontinuedtoimprovetheNIRcollectionefficiencybyPlanarlensstructure. According to the newest optical simulation results, Planar lens withmulti-level can improve NIR collection efficiency obviously that is better thanpreviousPlanar lenswithbinarylevel.Thephysicalstructureandprocesswillbealsointroducedinthispaper.SphericalmicrolensesisapopularsolutionforCMOSimagesensorbecauseofitsexcellentcapabilitytoconcentrateincominglightonthephotodiode.Inthepasttime,ourtraditionalmaterialandprocessonlycanreach3µmmicro lensheightunder 10µm pixel size. It can’t meet the requirement for common SPAD’sstructuredefinitely.Tosolvethisproblem,wedevelopedanewsolutiontomeet10µmmicrolensheightunder20µmpixelsize.Accordingtotestingresult,theNIRcollectionefficiencycanbeincrease60%whencomparetowithoutmicrolens.

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AngleSensitiveSPADs

AlyoshaMolnar

CornellUniversity

This talk brings together twodifferentmodalities of light sensing: the fine timeresolutionandhigh sensitivityprovidedby theGeiger-modebehaviorof SPADs,and the angular resolution provided by pixel-scale diffractive structures placedimmediately above each light sensor. When implemented in a standardsemiconductor manufacturing process, these two functions (Single-photondetection and angle sensing) rely on different fabrication steps, with SPADfunctionimplementedintheFEOLsemiconductorstructures,andanglesensitivityrelyingonengineeringtheBEOLinterconnectanddielectriclayers.Interestingly,these two techniques also take advantage of the two different behaviors ofphotons: SPAD function depends upon the particle-like behavior of light, whileincident angle is computed from photons’ wave-behavior, based on spatialgradientsintheincomingphotons’phase.This talk will first review techniques for making pixels (or small collections ofpixels)usefullyanglesensitive,aswellassomeofthevariantsonanglesensitivepixels, and some of the ways they can be used. How to best combine thesestructureswithstandardSPADstructureswillbediscussed,andanexamplearrayof angle-sensitive SPADs will be presented. Ways in which the two types ofinformationgatheredbyanangle-sensitiveSPADcanbemeaningfullycombinedwillalsobediscussed.Severalexampleapplicationsofsuchmulti-modalsensorswill be discussed, including lens-less, filter-less FLIM, and “depth-field imaging”,where time-of-flight and light-filed techniques are combined. Finally, potentialfutureapplicationswillbediscussed,aswellasimplicationsforoptimalco-designof angle-sensitive SPADs, both at the sensor level, and in conjunction withassociatedelectronics.

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ASPAD-based,DirectTimeofFlight,64Zone,15fps,ParallelRangingDeviceBasedon40nmCMOSSPAD

Technology

BruceRaeandPascalMellot

STMicroelectronics

WepresentaSPAD-based,directtimeofflight,multi-zoneparallelrangingdevicebasedonSTMicroelectronics40nmCMOSSPADtechnology.Capableofstreamingup to 64 zones at 15fps, this all-in-one device includes on-chip VCSEL driver(coupled to in-module VCSEL),multi-target detectionwith parallel 8x8 ambientandsignalmapgeneration.Takingadvantageofthe40nmadvanceddigitalnode,16 parallel full histogram read-out channels have been implemented, eachcapableofcapturingmultipletargetswithinthe“zone”fieldofview.Featuringanon-board 32bit 250MHzMCUwith custom hardware acceleration features, thedevice is capable of extensive HQ processingwithmultiple target and statisticsreporting.AreconfigurableSPADarrayhasbeen implementedofferingflexibilityinzonesize,locationandbinning.Withamaximumrangingdistanceof5metresand millimetre range accuracy, this device is suitable for a wide range ofapplications.

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SPADBasedStreakCameras

WilfriedUhring

UniversityofStrasbourg

During the measurement of a fast event with a high speed camera, theinstantaneous pixel rate can be as large as a few Giga pixel/s to several Terapixel/S or even some Peta pixel/s depending of the camera’s technology. Thishugedatarateismandatoryfortherecordofauniquephenomenonthatcan’tberepeatedandthusthemeasurementhastobeoperatedinthesingleshotmode.In the field of high speed imaging, the streak imaging is a specific imageacquisition paradigm that offers the best temporal resolution. Contrary to theframeimagingwhereafullimageistakenwithtwodimensionsinboththexandyaxisatagivensamplingrate,thesocalledstreak imagingconsists inacquiringthescenetobeobservedthroughasingle lineonlyonthexaxis.At thecostofthe looseofa spatialdimension, foragivenandconstantoverallpixel rate, thetemporal resolution can be enhanced by a factor equivalent to the number ofrow.Indeed,thehistoryofhighspeedimagingshowsthatstreakimagersoffersatemporalresolutionabout100to1000timesbetterthanframeimagerandthatwhatever theused technology, suchas theopto-mechanic, the vacuum tubeorthesolidstatedevices.The time resolved or time gated photon counting is an image acquisitionparadigm that imply that the phenomenon can be repeated as only a poorinformationisfetchedeachtimetherecurrentphenomenonismeasured.Inthiscase the required sample rate is drastically reduced and the streak imagingparadigmseems lessuseful.Nevertheless, the streak imagingapproach releasesthespaceconstraintsinherenttothematrixarchitectureoftheframesensor,andthe sensor can be enhancedwith bothmore performing electronics and smartoperation.Forinstance,ahistogramconstructionembeddedprocessingmakesitpossibletoradicallyreducetheamountofdatawhileachievingthefastestphotoncountinginsidethesensor.

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SpaceSecureCommunicationsusingSinglePhotons

PaoloVilloresi

UniversityofPadova

The paradigm shift that Quantum Communications represent vs. classicalcounterpart allows envisaging the global application of Quantum Informationprotocolsasthecryptographickeydistributionaswellasoftheuseofthequbitsasaprobe for fundamental testsofQuantumMechanicsandGravityona scalebeyondterrestrial limits.Singlephotonsarethenaturalcarrierofthedegreesoffreedom needed to encode the qubits, as they may travel with very littledecoherence and be detected efficiently. We shall report on the extension oftestsonbasicprinciplesofQuantumMechanicsusingQuantumCommunicationsto an orbiting terminal in Space using different encoding in single photons.Indeed,itwaspossibletodemonstratetheQuantumCommunicationswithLow-Earth-Orbitsatellitesusingpolarizationdegreeoffreedomtoencodethequbits.Temporal modes were used to demonstrate the quantum interference along aSpacechannelwillbealsodescribed.TherecentresultsontheextensiontoSpaceof the Gedankenexperiment proposed by John Wheeler on the wave- particleduality,thenabouttheverynatureofthequantumentities,willbedescribed.

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BCDSPADImagerwithReconfigurableMacropixelsforPhotonCounting,TimingandCoincidenceDetection

F.Villa,D.Portaluppi,E.Conca,F.Zappa

PolitecnicodiMilano,DipartimentodiElettronica,InformazioneeBioingegneria

Arrayof SinglePhotonAvalancheDiodes (SPADs)aregaining increasing interestboth in the scientific research and in industry automation and automotiveassistancesystems.Single-photonsensitivity,precisetiminginformation,highfill-factor,enhancedefficiencyinthenearinfra-redandbackgroundlightrobustnessare the main requirements for most of these applications. We designed andfabricatedasingle-photonsensitiveimagerbasedonSPADsina0.16µmBipolarCMOS DMOS (BCD) technology with 16×16 reconfigurable macropixels. Theinnovative pixel architecture includes 4 separate detectors with independentactivetime-gatingandquenchingcircuit,asharedTime-to-DigitalConverter(TDC)with 75 ps resolution, 4 independent photon counters, andmultiple operationmodes. SPADs have a square shape (32µm×32µm)with rounded corners and100µmpitch,resultingin9.6%fill-factor.TheTDCisconstitutedbya7-bitcoarsecounter and two 5-bit fine interpolators, namely the global START interpolatorandthe in-pixelSTOPone. Interpolatorsaremadeof fast latches,whichsamplethestatusofmultiphase-clocksgeneratedbyaglobalDelayLockedLoop(DLL)atthe rising edge of the input event; then, a thermometric-to-binary decodergenerates the 5-bit interpolation result. Multiple events can be converted andstoredduringeachframeofacquisitionandanarbitrationlogicpreservesspatialinformation among the 4 SPADs connected to the shared TDC, by storing theresultinthememorycellassociatedwiththetriggeringSPAD.Lightintensityandphoton arrival time can be measured simultaneously for capturing 2D and 3Dimagesof thescene ina singleshot (frame)oronlycountingcanbeenabled toreduce power consumption and increase achievable frame-rate when timinginformationisnotneeded.Photon-coincidenceonmultipledetectorsisexploitedto reduce the effect of high background levels, e.g. in LIDAR applications withstrongambientlight.Theachieveddetectionperformanceisamongthebestreportedintheliterature:PDEof60%at500nmwavelengthandstill12%at800nm;lowdarkcountrateof<0.2cps/µm2(countspersecondperunitarea);afterpulsingprobabilitylowerthan1%with50nsdead-time; temporal responsewith30ps full-widthathalfmaximum and less than 50 ps diffusion tail time constant. According to apreliminarycharacterizationtheTDCsingleshotprecisionis115psFWHM.

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APPLICATIONS

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ComputationalSingle-photonImaging

GordonWetzstein

StanfordUniversity

Time-of-flight imaging and LIDAR systems enable 3D scene acquisition at longrange using active illumination. This is useful for autonomous driving, roboticvision, human-computer interaction and many other applications. Thetechnological requirements on these imaging systems are extreme: individualphotoneventsneedtoberecordedandtime-stampedatapicosecondtimescale,whichisfacilitatedbyemergingsingle-photondetectors.Inthistalk,wediscussanew class of computational cameras based on single-photon detectors. Theseenable efficientways for non-line-of-sight imaging (i.e., looking around corners)andefficientdepthsensingaswellasotherunprecedentedimagingmodalities.

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ImagingattheSpeedofLight

DanieleFaccio

UniversityofGlasgow

Iwill talkaboutsomeof theexcitingresearchthat is takingplace in the fieldofultrafastimagingandimagingwithsinglephotoncountingcameras.Singlephotonsensitivity and short acquisition times enable the direct observation of a lightpulse propagating in air and we will discuss some results in which we use thetiminginformationtomeasuredlightpropagation.Wewillalsodiscussapplicationstothetrackingofobjectshiddenfromview.Ourapproachisessentiallybasedonnon-line-of-sightlaserrangingthatreliesontheabilitytosendlightaroundanobstacleusingascatteringfloorandtothendetectthe return signal from a hidden object with only a few seconds of acquisitiontime.We can track amovingobject located up to a fewmetres away from thecamerawithcentimetreprecision.Wewilldiscussrecentprogressinthisfield,includingthelong-distancedetectionandmachinelearningappliedtotheidentificationofhiddenpeople.Finally, we will discuss applications of time-resolved single photon counting toimagingthroughdiffusivemedia.

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SPADArrays:fromSingle-MoleculeDetectiontoWide-FieldPhasorFluorescenceLifetimeImaging

X.Michalet1,A.Ingargiola1,M.Segal1,S.Weiss1,A.Gulinatti2,I.Rech2,M.Ghioni2,S.Burri3,A.Ulku3,C.Bruschini3,E.Charbon3

1. DepartmentofChemistry&Biochemistry,UCLA2. DipartimentodiElettronica,InformazioneeBioingeneria,Politecnicodi

Milano3. SchoolofEngineering,EPFL

TheadventoftheSlikTMsingle-photonavalanchediodeintheearly90’shasmadesingle-molecule spectroscopy, and specifically, single-molecule FRET, a practicalreality.Similarly,custom-technologySPADarraysdevelopedsincethemid2000’s,haveopenedup theway tohigh-throughputsingle-moleculedetection,bringingus one step closer to mainstream applications of these techniques, as well asofferingexcitingnewbasicresearchopportunities.Meanwhile,CMOSSPADarraysare closing the gap in termsof sensitivity,while pushing ahead in termsof size(numberofpixels)andembeddedfunctionalities.These“imagers”aremuchmorethanfancycameras,andofferexcitingnewprospects forbiomedical imaging, inparticularforfluorescencelifetimeimaging,withapplicationsininvivomolecularimaging, fluorescence tomographyand image-guidedsurgery. Inbothcases, theabilitytopreprocessrawdata inFPGAbeforetransferring ittotheuserappearsalmost as an important as the raw detection capabilities of these devices, andraisesinterestingchallengesonhowtolettheuserharnessthispotential.

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LIDARsforAutomotiveandIndustrialApplications

LucioCarrara

Fastree3D

Flash LIDAR technology is anticipated as a prime enabler of advanced drivingassistance and autonomous navigation in automotive and machine visionapplications.While SPAD-based sensors are known to provide the flexibility and reliabilityrequiredbysuchapplications,theirintegrationinfull-fledgedcamerasystemsisacomplexandmultidisciplinarytask,whichdemandsbalancingmultipleconflictingrequirements.ThistalkwillexplorethefundamentalchallengesrelatedtodesigningflashLIDARsystems based on SPADs for automotive and machine vision applications. Keychallenges,suchastheresilienceagainstambient light,optical interference,andthe reliability of measurements, will be introduced, and importantimplementation trade-offs will be shown in the context of cutting-edge systemarchitectures.

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Time-DomainNearInfraredSpectroscopy

DavideContini

PolitecnicodiMilano

Diffuseopticsstudiesbiological tissuesbymeansofphotons.Applicationsrangefrom neuroscience to the food quality assessment. Time-Domain Near InfraredSpectroscopy (TD-NIRS) is one of the technique used to measure opticalproperties of a turbid medium like biological tissues. From a physical point ofview, timedomainmeasurementsare themoststraightforwardand informativeintheframeworkofdiffuseoptics.Unfortunately,itslimitintermsofrobustness,cost and complexity prevented its diffusion and applications outside researchlaboratories. In the last decade, TD-NIRS is undergoing fascinating technologyadvancements, permitting to overcome its limitations. With respect to otheroptical techniques, TD-NIRS systems guarantee higher information content,sensitivity,penetration inthetissueand insensibility tomotionartifact. Inordertomaximize their performances, 4 conditions are needed, being nowadays themain technological challenges: i) dense distribution of miniaturized pulsedsources to maximize the injected power; ii) dense distribution of miniaturizedprobe-hosted TD detectors to maximize the harvesting of diffused light (SPAD,array of SPADs, SiPM) ; iii) fast time-gating capability to implement the gatedacquisition technique, thus achieving the largest dynamic range of acquisition(gatedSPADs);iv)highthroughputcompactelectronicsforphotontiming.Inthefuture with the achievement of these 4 conditions, TD-NIRS could potentiallyreachapenetrationdepthof6cminhumantissues,withthepossibilitytonon-invasively probe organs, as for example the lung or the heart,which are todayunreachablewiththestandardopticaltechniques.

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ImagingwithEntangledPhotons

L.Gasparini1,M.Perenzoni1,H.Xu1,L.Parmesan1,M.MorenoGarcia1,D.Stoppa1,B.Bessire2,M.Unternährer2,A.Stefanov2,D.L.Boiko3

1. FondazioneBrunoKessler,viaSommarive18,Povo,38123Trento,Italy2. InstituteofAppliedPhysics,UniversityofBern,3012Bern,Switzerland

3. CentreSuissed’ÉlectroniqueetdeMicrotechnique,Jaquet-Droz1,CH-2002Neuchâtel,Switzerland

SpatiallyentangledphotonsbehaveasasinglequantumobjectcharacterizedbyitsdeBrogliewavelength.Thisquantumobjectofferssuper-resolutioncapabilitiesas compared to imaging with a classical light. In both cases, the Rayleighresolutionlimit issetatahalfofthewavelength,butinthecaseofNentangledphotons,theeffectivewavelengthisreducedbyafactorofN.Inordertobenefitfromsuchsuper-resolutioncapabilities,adedicateddetector isneeded,capableof implementinghigh-ordercross-correlationsofarrival timecoincidenceeventsbetweenNdetectorpixels.Coincidences forpixelpairs, triads, tetradsetc.mustbe measured within a time bin. Such functionality renders the detectorarchitecturetobedrasticallydifferentfromexistingstate-of-the-arttime-resolvedsingle-photondetectors,e.g. largeSPADarrays for timeresolvedmeasurementsimplemented in CMOS. One can easily spot that such detector system wouldrapidly reachany feasible limitsof thedata transmission ratesanddatastoragecapabilities to handle all possible multi-pixel combinations if specific measureswere not taken in the design. Here we report on SuperEllen sensor developedwithin the project SUPERTWIN for super-resolution imaging applications withcorrelatedphotons.Itisimplementedin150nmCMOStechnologyandconsistsof32x32pixelswithsub200ps timingcapabilityandahigh fill factorof20%.Wewill present first measurements with this sensor showing the potential of thetechnologyforquantumopticsimaging.Weshowresultsobtainedwithentangledphotonpairsandbyrecording4-thordercorrelationimageswiththermallight.

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ListofParticipants

Lastname Firstname Affiliation ACCARINO Claudio Univ.ofGlasgowANHUT Tiemo CarlZeissGroupANTOLOVIC IvanMichel TUDelft/EPFLARDELEAN Andrei EPFLASADA Kunihiro Univ.ofTokyoBOSO Gianluca IDQuantiqueBOURREAU Christophe ViaviSolutionsBROCKHERDE Werner FraunhoferIMSBRUSCHINI Claudio EPFLBUETTGEN Bernhard AppleBURRI Samuel TUDelft/USI/EPFLCANER Onal WaymoLLCCAPASSO Massimo FondazioneBrunoKesslerCARIMATTO AugustoJosé TUDelftCARMONA-GALAN Ricardo CSICCARRARA Lucio Fastree3DCHANDRAMOULI Paramanand Univ.ofSiegenCHARBON Edoardo EPFLCONTINI Davide PolitecnicodiMilanoCANTINI Cosimo ForimtechDEBONDT Joris SONYSDSDIEBEL Falko IbeoAutomotiveSystemsDRADER Marc AppleFACCIO Daniele GlasgowUniv.FENIGSTEIN Amos TowerJazzFIELD Ryan QuanergySystems,Inc.GILBOA Niv AppleGIUDICE Andrea MicroPhotonDevicesGNECCHI Salvatore SensLTechnologiesGOLA Alberto FondazioneBrunoKesslerGOLANSKI Dominique STMicroelectronicsGONG Ting Fastree3DGOVE Robert SynapticsGRAMUGLIA Francesco EPFLGULINATTI Angelo PolitecnicodiMilanoGYONGY Istvan Univ.ofEdinburghHAIGH Richard KromekGroupplc

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Lastname Firstname Affiliation HENDERSON Robert Univ.ofEdinburghHURWITZ Jed AnalogDevicesINNOCENT Manuel ONSemiconductorITZLER Mark ArgoAIJACKSON Carl SensLTechnologiesKAPPEL Robert amsAGKHAN Brigitte EPFLKOROBOV Vladimir ONsemiconductorsKÜHNHOLD Ralf ElmosSemiconductorAGKUIJK Maarten VrijeUniv.BrusselLEE Myung-Jae EPFLLENOBLE Julie EPFLLINDNER Scott EPFLMAMDY Bastien STMicroelectronicsMARSDEN Edward KromekGroupplcMEDINALOPEZ CamiloErnesto SonyDepthsensingSolutionsMELLOT Pascal STMicroelectronicsMEYNANTS Guy amsAGMICHALET Xavier UCLAMOLNAR Alyosha CornellUniv.MOORE Kevin STMicroelectronicsMORIMOTO Kazuhiro EPFLMOUSSY Norbert CEA-LETIMUNTEAN Andrada EPFLNICLASS Cristiano ApplePACHE Christophe CSEMPADMANABHAN Preethi EPFLPELLEGRINI Sara STMicroelectronicsPERENZONI Matteo FBKRAE Bruce STMicroelectronicsREGAZZONI Francesco USIRIEDLBERGER Franz LFoundryRUSKOWSKI Jennifer FraunhoferIMSSAGAWA Nobuaki FUJIFILMElectronicMaterialsSTOPPA David amsAGSUN Pengfei X-FABSemiconductorSÜSS Andreas imecTAGUCHI Yoshinori FUJIFILMTERANISHI Nobukazu Univ.ofHyogo

3

Lastname Firstname Affiliation THIL Christophe SICKAGTOSI Alberto PolitecnicodiMilanoUHRING Wilfried Univ.ofStrasbourgULKU ArinCan EPFLVANSIELEGHEM Edward ImecVENIALGO Esteban TUDelftVERGHESE Simon Waymo/AlphabetVILLA Federica PolitecnicodiMilanoVORNICU Ion CSICWALKER Richard PhotonForceLtdWETZSTEIN Gordon StanfordUniv.WICHT Sebastian X-FABSemiconductorWU Ken VisEraTechnologiesXIMENES Augusto TUDelftYAMASHITA Yuichiro tsmcZAPPA Franco PolitecnicodiMilanoZHANG Chao TUDelftZIMMER Alexander X-FABSemiconductorZWÖLFER Ulrich SICKAG

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