High-energy sub-nanosecond optical pulse generation with a semiconductor laser diode for pulsed TOF laser ranging utilizing the single photon detection approach

Bulk and quantum well laser diodes with a large equivalent spot size of da/Γa ≈ 3 µm and stripe width/cavity length of 30 µm/3 mm were realized and tested. They achieved a pulse energy and pulse length of the order of ~1 nJ and ~100 ps, respectively, with a peak pulse current of 6–8 A and a current pulse width of 1 ns. The 2D characteristics of the optical output power versus wavelength and time were also analyzed with a monochromator/streak camera set-up. The far-field characteristics were studied with respect to the time-homogeneity and energy distribution. The feasibility of a laser diode with a large equivalent spot size in single photon detection based laser ranging was demonstrated to a non-cooperative target at a distance of a few tens of meters

Association of Forced Vital Capacity with the Developmental Gene <i>NCOR2</i>

Background Forced Vital Capacity (FVC) is an important predictor of all-cause mortality in the absence of chronic respiratory conditions. Epidemiological evidence highlights the role of early life factors on adult FVC, pointing to environmental exposures and genes affecting lung development as risk factors for low FVC later in life. Although highly heritable, a small number of genes have been found associated with FVC, and we aimed at identifying further genetic variants by focusing on lung development genes. Methods Per-allele effects of 24,728 SNPs in 403 genes involved in lung development were tested in 7,749 adults from three studies (NFBC1966, ECRHS, EGEA). The most significant SNP for the top 25 genes was followed-up in 46,103 adults (CHARGE and SpiroMeta consortia) and 5,062 chi

Single-photon -ilmaisuun perustuva lasertutka

Diplomityössä tutkittiin suurella taajuudella pulssitettavaan kapeaan laserpulssiin sekä aikaportitettuun single photon ilmaisimeen perustuvan lasertutkan toteutettavuutta ja suorituskykyä. Tutkimuksessa toteutettiin lasertutkan lähetinvastaanotin, jolle suoritettiin verifiointi- ja suorituskykymittaukset. Lähettimessä hyödynnettiin puolijohdelaserilla tuotettujen energialtaan nJ- sekä puoliarvoleveydeltään 100 ps -luokan laserpulsseja sekä vastaanottimessa digitaalista CMOS SPAD ilmaisinta. Puolijohdelaserin herätteenä käytettiin puoliarvoleveydeltään nanosekunti- ja amplitudiltaan ampeeriluokan virtapulsseja. Virtapulssitinelektroniikassa käytettiin nopeaa MOSFET-transistoria virtapulssitintopologian edellyttämänä kytkimenä. Lasertutkan pulssitustaajuusalue oli 100–1000 kHz. Lähettimelle suoritetuilla mittauksilla tutkittiin toteutetun virtapulssittimen tuottamien virtapulssien ominaisuuksia sekä eräiden bulk- ja yhden kvanttikaivolaserrakenteen optisia vasteita kyseisille virtapulssiherätteille. Laserrakenteen aktiivisen tilavuuden koosta riippuen optisten pulssien maksimi tehot vaihtelivat välillä 2–12 W ja puoliarvoleveydet 80–130 ps. TOF-etäisyysmittausjärjestelmälle 100 kHz pulssitustahdilla suoritetuilla aikavälimittauksilla määritettiin vastaanottimen hyötyfotoni-ilmaisutahti, jota verrattiin tutkayhtälön antamaan teoreettiseen tulokseen. Mittausetäisyyksillä 24,5 m ja 50 m saatujen mittaustulosten ja tutkayhtälön välillä havaittiin selkeä yhdenmukaisuus. Järjestelmän kertamittaustarkkuuden määrittävä mittaus antoi vastaanotetun optisen pulssin puoliarvoleveydeksi 150 ps vastaten 22 mm erottelukykyä. Walk-virhe -mittaustulokset osoittivat SPAD-ilmaisimen etäisyysmittaustuloksiin vaikuttavan systemaattisen virhelähteen mittauskohteiden erilaisten heijastuskertoimien vaikutuksesta olevan 60 mm. Voimakkaassa taustavalaistuksessa suoritettujen aikaportitusmittausten tuloksista nähdään 10 ns etäisyydelle hyötypulssin etureunasta asetetun aikaportin yli 600 kertainen parannus vastaanottimen hyötypulssi-ilmaisutodennäköisyyteen 308 ns etäisyydelle hyötypulssin etureunasta asetettuun aikaporttiin verrattuna. Lasertutkan vastaanottimen toteutuksessa käytetyn CMOS SPAD ilmaisimen toimivuus ja suorituskyky osoittivat CMOS-prosessilla toteutettavan kompaktin TOF-etäisyysmittausjärjestelmän olevan käytännön sovelluksissa mahdollinen. Suorituskykymittaustulokset osoittivat lasertutkan senttimetriluokan mittaustarkkuuden kymmenien ja jopa satojen metrien mittausetäisyydellä

2D CMOS SPAD array techniques in 1D pulsed TOF distance measurement applications

Abstract The goal of the research was to study the characteristics, performance and feasibility of a pulsed time-of-flight 1D laser radar system employing a 2D SPAD detector array in conjunction with a custom-made laser diode producing high energy and high-speed laser pulses. The research included the characterization and comparison of custom-made QW and bulk laser diodes operating in enhanced gain switching mode and producing laser pulses with a total energy of ~1–5 nJ and an FWHM of ~100 ps at pulsing rates >100 kHz. The receiver module was a purpose-built single-chip CMOS IC incorporating a 2D 9x9 SPAD array and a 10-channel TDC circuit enabling parallel SPAD-specific TOF measurements. The key performance parameters of the laser radar system are intrinsic timing walk error ~5 cm (dynamic range ~1:100 000), linearity ± 0.5 mm, signal detection rate ~28% (target distance 34 m and reflectivity 11%) and precision ~2 cm. The total energy of a probe pulse was 0.6 nJ and the diameter of the circular receiver aperture ~20 mm. The selectable subarray feature of the receiver IC enables laser spot tracking on the detector array while maintaining a small effective field of view, thus reducing background radiation-induced noise detections, and offering prospect of walk error free measurement results. Detection time gating proved an effective means for signal-to-noise ratio improvement under conditions of high-level background radiation. Feasibility studies demonstrated high spatial accuracy of the system in practical settings when performing non-contact human heart rate measurement and when distinguishing individual free-falling snowflakes. The implementation and performance of the 1D laser radar system demonstrated the viability of the proposed technology as an alternative along with a conventional laser radar operating in the linear detection mode for high performance, compact and cost-effective laser radar applications.Tiivistelmä Väitöstyössä tutkittiin kaksiulotteista SPAD-ilmaisinmatriisiteknologiaa sekä suurienergisiä ja lyhyitä laserpulsseja hyödyntävän 1D-lasertutkan ominaisuuksia, suorituskykyä ja toteutettavuutta. Tutkimuksessa karakterisoitiin ja vertailtiin erikoisrakenteisia ”enhanced gain switching”-moodissa toimivia bulk- ja kvanttikaivolaserdiodeja (QW), joilla voidaan tuottaa ~1–5 nJ sekä ~100 ps (puoliarvoleveys) laserpulsseja >100 kHz pulssitustahdilla. Tutkimustyössä kehitetyn ja toteutetun pienikokoisen lasertutkan vastaanottimena käytettiin tarkoitukseen suunniteltua integroitua CMOS-piiriä, joka sisältää 9x9 SPAD ilmaisinmatriisin sekä 10-kanavaisen aika-digitaalimuuntimen (TDC) rinnakkaisia SPAD-kohtaisia laserpulssin kulkuaikamittauksia varten. Lasertutkan keskeiset suorituskykyparametrit ovat kompensoimaton ajoitusvirhe ~5 cm (dynaaminen alue ~1:100 000), lineaarisuus ± 0,5 mm, signaalin ilmaisutahti ~28 % (kohteen etäisyys 34 m, heijastuskerroin 11 %) ja kertamittaustarkkuus ~2 cm. Laserpulssin kokonaisenergia ja vastaanottimen apertuurin halkaisija ovat 0,6 nJ ja ~20 mm. Aktiivinen 3x3 osailmaisinmatriisi minimoi vastaanottimen efektiivisen näkökentän (FOV) vähentäen taustasäteilystä aiheutuvia ilmaisuja ja osailmaisinmatriisin valintatoiminto mahdollistaa laserspotin seurannan ilmaisinmatriisin pinnalla sekä ajoitusvirheettömät etäisyysmittaustulokset. Ilmaisimen aikaportitustoimintoa voidaan käyttää mittauksen signaali-kohinasuhteen (SNR) parantamiseen taustasäteilyn ollessa voimakasta. Lasertutkan spatiaalisen tarkkuuden sekä mittausnopeuden havainnollistamiseksi suoritetuissa soveltuvuustutkimuksissa mitattiin koehenkilön sydämen syke ilman fyysistä kontaktia usean metrin etäisyydeltä sekä havaittiin yksittäisistä lumihiutaleista aiheutuvia kaikuja lumisateessa. Tutkimuksen tuloksiin perustuen kehitetty teknologia on toimiva vaihtoehto ns. perinteisen lineaariseen ilmaisuun perustuvan lasertutkan ohella suorituskykyisiin, kompakteihin ja kustannustehokkaisiin lasertutkasovelluksiin

Compact laser radar based on a subnanosecond laser diode transmitter and a two-dimensional CMOS single-photon receiver

Abstract A pulsed TOF laser radar utilizing the single-photon detection mode has been implemented, and its performance is characterized. The transmitter employs a QW double-heterostructure laser diode producing 0.6 nJ∕100 ps laser pulses at a central wavelength of ∼810 nm. The detector is a single-chip IC manufactured in the standard 0.35-μmHV CMOS process, including a 9 × 9 single-photon avalanche diode (SPAD) array and a 10-channel time-to-digital converter (TDC) circuit. Both the SPAD array and the TDC circuit support a time gating feature allowing photon detection to occur only within a predefined time window. The SPAD array also supports a 3 × 3 SPADs subarray selection feature to respond to the laser spot wandering effect due to the paraxial optics and to reduce background radiation-induced detections. The characterization results demonstrate a distance measurement accuracy of þ∕ − 0.5 mm to a target at 34 m having 11% reflectivity. The signal detection rate is 28% at a laser pulsing rate of 100 kHz. The single-shot precision of the laser radar is ∼20 mm (FWHM). The deteriorating impact of high-level background radiation conditions on the SNR is demonstrated, as also is a scheme to improve this by means of detector time gating

A laser radar based on a “impulse-like” laser diode transmitter and a 2D SPAD/TDC receiver

Abstract A pulsed TOF laser radar has been implemented and its performance characterized. The transmitter applies a QW double-heterostructure laser diode producing 0.6 nJ/ 100 ps laser pulses at the central wavelength of ~ 817 nm. The detector is a single-chip IC, manufactured in the standard 0.35 μm HV CMOS process, including a 9×9 SPAD array and a 10-channel TDC circuit. Both the SPAD array and the TDC circuit support a time gating feature allowing photon detection only to occur within a predefined time window. The SPAD array also supports the sub-array selection feature in order to respond to the laser spot wandering effect due to paraxial optics. A sub-array is a 3×3 SPAD array freely chosen within a 9×9 SPAD array. The characteristic measurement results demonstrate the measurement range of tens of meters with a linearity precision +/- 0.5 mm to the 11% target reflectivity and at pulsing frequency of 100 kHz. The distance dependent detection rate varies from 28% to 500%, thus providing a high measurement rate. The single-shot precision is ~ 20 mm. The deteriorating impact of high-level background radiation conditions on the SNR has been demonstrated as well as a scheme to improve it by detector time gating

GenZ white paper: strengthening human competences in the emerging digital era

We are witnessing an emerging digital revolution. For the past 25–30 years, at an increasing pace, digital technologies—especially the internet, mobile phones and smartphones—have transformed the everyday lives of human beings. The pace of change will increase, and new digital technologies will become even more tightly entangled in human everyday lives. Artificial intelligence (AI), the Internet of Things (IoT), 6G wireless solutions, virtual reality (VR), augmented reality (AR), mixed reality (XR), robots and various platforms for remote and hybrid communication will become embedded in our lives at home, work and school. Digitalisation has been identified as a megatrend, for example, by the OECD (2016; 2019). While digitalisation processes permeate all aspects of life, special attention has been paid to its impact on the ageing population, everyday communication practices, education and learning and working life. For example, it has been argued that digital solutions and technologies have the potential to improve quality of life, speed up processes and increase efficiency. At the same time, digitalisation is likely to bring with it unexpected trends and challenges. For example, AI and robots will doubtlessly speed up or take over many routine-based work tasks from humans, leading to the disappearance of certain occupations and the need for re-education. This, in turn, will lead to an increased demand for skills that are unique to humans and that technologies are not able to master. Thus, developing human competences in the emerging digital era will require not only the mastering of new technical skills, but also the advancement of interpersonal, emotional, literacy and problem-solving skills. It is important to identify and describe the digitalisation phenomena—pertaining to individuals and societies—and seek human-centric answers and solutions that advance the benefits of and mitigate the possible adverse effects of digitalisation (e.g. inequality, divisions, vulnerability and unemployment). This requires directing the focus on strengthening the human skills and competences that will be needed for a sustainable digital future. Digital technologies should be seen as possibilities, not as necessities. There is a need to call attention to the co-evolutionary processes between humans and emerging digital technologies—that is, the ways in which humans grow up with and live their lives alongside digital technologies. It is imperative to gain in-depth knowledge about the natural ways in which digital technologies are embedded in human everyday lives—for example, how people learn, interact and communicate in remote and hybrid settings or with artificial intelligence; how new digital technologies could be used to support continuous learning and understand learning processes better and how health and well-being can be promoted with the help of new digital solutions. Another significant consideration revolves around the co-creation of our digital futures. Important questions to be asked are as follows: Who are the ones to co-create digital solutions for the future? How can humans and human sciences better contribute to digitalisation and define how emerging technologies shape society and the future? Although academic and business actors have recently fostered inclusion and diversity in their co-creation processes, more must be done. The empowerment of ordinary people to start acting as active makers and shapers of our digital futures is required, as is giving voice to those who have traditionally been silenced or marginalised in the development of digital technology. In the emerging co-creation processes, emphasis should be placed on social sustainability and contextual sensitivity. Such processes are always value-laden and political and intimately intertwined with ethical issues. Constant and accelerating change characterises contemporary human systems, our everyday lives and the environment. Resilience thinking has become one of the major conceptual tools for understanding and dealing with change. It is a multi-scalar idea referring to the capacity of individuals and human systems to absorb disturbances and reorganise their functionality while undergoing a change. Based on the evolving new digital technologies, there is a pressing need to understand how these technologies could be utilised for human well-being, sustainable lifestyles and a better environment. This calls for analysing different scales and types of resilience in order to develop better technology-based solutions for human-centred development in the new digital era. This white paper is a collaborative effort by researchers from six faculties and groups working on questions related to digitalisation at the University of Oulu, Finland. We have identified questions and challenges related to the emerging digital era and suggest directions that will make possible a human-centric digital future and strengthen the competences of humans and humanity in this era

GenZ white paper:strengthening human competences in the emerging digital era

Executive summary We are witnessing an emerging digital revolution. For the past 25–30 years, at an increasing pace, digital technologies—especially the internet, mobile phones and smartphones—have transformed the everyday lives of human beings. The pace of change will increase, and new digital technologies will become even more tightly entangled in human everyday lives. Artificial intelligence (AI), the Internet of Things (IoT), 6G wireless solutions, virtual reality (VR), augmented reality (AR), mixed reality (XR), robots and various platforms for remote and hybrid communication will become embedded in our lives at home, work and school. Digitalisation has been identified as a megatrend, for example, by the OECD (2016; 2019). While digitalisation processes permeate all aspects of life, special attention has been paid to its impact on the ageing population, everyday communication practices, education and learning and working life. For example, it has been argued that digital solutions and technologies have the potential to improve quality of life, speed up processes and increase efficiency. At the same time, digitalisation is likely to bring with it unexpected trends and challenges. For example, AI and robots will doubtlessly speed up or take over many routine-based work tasks from humans, leading to the disappearance of certain occupations and the need for re-education. This, in turn, will lead to an increased demand for skills that are unique to humans and that technologies are not able to master. Thus, developing human competences in the emerging digital era will require not only the mastering of new technical skills, but also the advancement of interpersonal, emotional, literacy and problem-solving skills. It is important to identify and describe the digitalisation phenomena—pertaining to individuals and societies—and seek human-centric answers and solutions that advance the benefits of and mitigate the possible adverse effects of digitalisation (e.g. inequality, divisions, vulnerability and unemployment). This requires directing the focus on strengthening the human skills and competences that will be needed for a sustainable digital future. Digital technologies should be seen as possibilities, not as necessities. There is a need to call attention to the co-evolutionary processes between humans and emerging digital technologies—that is, the ways in which humans grow up with and live their lives alongside digital technologies. It is imperative to gain in-depth knowledge about the natural ways in which digital technologies are embedded in human everyday lives—for example, how people learn, interact and communicate in remote and hybrid settings or with artificial intelligence; how new digital technologies could be used to support continuous learning and understand learning processes better and how health and well-being can be promoted with the help of new digital solutions. Another significant consideration revolves around the co-creation of our digital futures. Important questions to be asked are as follows: Who are the ones to co-create digital solutions for the future? How can humans and human sciences better contribute to digitalisation and define how emerging technologies shape society and the future? Although academic and business actors have recently fostered inclusion and diversity in their co-creation processes, more must be done. The empowerment of ordinary people to start acting as active makers and shapers of our digital futures is required, as is giving voice to those who have traditionally been silenced or marginalised in the development of digital technology. In the emerging co-creation processes, emphasis should be placed on social sustainability and contextual sensitivity. Such processes are always value-laden and political and intimately intertwined with ethical issues. Constant and accelerating change characterises contemporary human systems, our everyday lives and the environment. Resilience thinking has become one of the major conceptual tools for understanding and dealing with change. It is a multi-scalar idea referring to the capacity of individuals and human systems to absorb disturbances and reorganise their functionality while undergoing a change. Based on the evolving new digital technologies, there is a pressing need to understand how these technologies could be utilised for human well-being, sustainable lifestyles and a better environment. This calls for analysing different scales and types of resilience in order to develop better technology-based solutions for human-centred development in the new digital era. This white paper is a collaborative effort by researchers from six faculties and groups working on questions related to digitalisation at the University of Oulu, Finland. We have identified questions and challenges related to the emerging digital era and suggest directions that will make possible a human-centric digital future and strengthen the competences of humans and humanity in this era