<p>The visible light photon counter (VLPC) is a high quantum efficiency (QE), Si-based, single-photon detector with high gain, low-noise multiplication, low timing jitter, and photon number resolution. While the VLPC has high QE in the visible wavelengths, the QE in the ultraviolet and infrared is low due to minimal absorption within the active layers of the device. In the ultraviolet, the absorption coefficient of Si is high and most of the incident photons are absorbed within the top contact of the device, whereas, in the infrared, Si is practically transparent. A number of applications in quantum information science would benefit from use of the VLPC if the QE was improved in the ultraviolet (e.g., state detection of trapped ions) and the infrared (e.g., long-distance quantum cryptography). This thesis describes the development of the ultraviolet photon counter (UVPC) and the infrared photon counter (IRPC), which are modified versions of the VLPC with increased QE in the ultraviolet and infrared wavelengths, respectively. The UVPC has a transparent metal Schottky contact to reduce absorption within the top contact of the VLPC, resulting in an increase in the QE in the ultraviolet by several orders of magnitude. The IRPC is a proposed device that has an InGaAs absorption layer that is wafer-fusion bonded to the VLPC. The band alignment of the resulting InGaAs/Si heterojunction is measured and shows a large discontinuity in the valence band that impedes carrier transport at the interface. A ultra-high vacuum wafer-bonding system was developed to understand the impact of the surface chemistry of the bonded wafers on the band alignment of the InGaAs/Si heterojunction of the IRPC.</p> / Dissertation

Šiame darbe yra aptariamos elektroninės mikroskopijos technologijos, elektroninių mikroskopų pagrindiniai veikimo principai, jais gaunami vaizdai bei apdorojimo metodai, funkcionalumo praplėtimo galimybės. Ypatingas dėmesys yra skiriamas – Artimo lauko optinio skenavimo mikroskopijai (SNOM – Scanning Near-Field Optical Microscopy). Darbo eigoje suprojektuota ir sukurta programinė įranga, leidžianti prie SNOM tipo mikroskopo prijungti nestandartinį grįžtamojo signalo įrenginį - fotonų skaitiklį. Fotonų skaitiklis yra daug jautresnis už standartiškai naudojamą fotodaugintuvą, tai leidžia SNOM mikroskopu atlikti naujus eksperimentus, kaip fluorescencijos tyrimas, tiriamųjų objektų žymėjimas kvantiniais taškais ir kt. Suprojektuota programa valdo SNOM naudodama sąsajas su mikroskopo programine įranga, sinchronizuoja fotonų skaitikliu gaunamus rezultatus, generuoja vaizdus, pateikia galimybes juos išsaugoti įvairiais formatais. Atlikus programos funkcionalumo tyrimą realiomis sąlygomis, buvo atrasti ir pašalinti programos trūkumai (susiję su sinchronizacija ir SNOM zondo veikimo ypatumais), bei nustatytos fotonų skaitiklio greitaveikos ribos, maksimalios fotonų skaičiaus reikšmės, rekomenduojama matavimo periodo trukmė. Darbe naudojamo fotonų skaitiklio greitaveikos problemoms spręsti pasiūlytas fotonų skaitiklio vienlustės sistemos projektas. Vienlustei sistemai sukurti buvo naudojami duomenys, surinkti programinės įrangos kūrimo ir testavimo metu. Pateikiami vienlustės sistemos... [toliau žr. visą tekstą] / This paper describes technologies used in electronic microscopy, mainly SNOM (Scanning Near-Field Optical Microscopy) and functionality extension possibilities. Software that enables using a photon counting unit as a supplementary input device was designed and presented. The photon counting device is much more sensitive than standard input device, thus new experiments as fluorescence research and Q-dot marking becomes available. The designed software collects data from photon counting unit and utilizes scripts to link with default SNOM software that controls probe movement. While testing the software, issues related to latency and synchronization helped to find out timing limits and optimal probe movement paths. To improve quality and speed of the whole scanning process a system-on-chip (SoC) project is presented. The paper provides details of SoC design, operation and limitations.

Ce travail porte sur la réalisation d'un microspectromètre SWIFTS (Stationary Wave Integrated Fourier Transform Spectrometer) incluant des compteurs de photons SNSPD (Superconducting Nanowire Single Photon Detector). Il met en œuvre un interféromètre intégré à guide d'onde en arête bouclé, en SiN, sous lequel sont disposés 24 nanofils supraconducteurs SNSPD en NbN échantillonnant les interférences au pas de 160nm, à une longueur d'onde centrée sur 1.55µm. La conception, l'étude des composantes optique et électronique, la fabrication et la caractérisation à 4.2K sont décrites, jusqu'à la mise en évidence d'une modulation de puissance lumineuse dans le guide conformément à la formation attendue d'interférences. Le SWIFTS-SNSPD constitue le premier dispositif optoélectronique supraconducteur à part entière, doublement intégré. Sa capacité unique d'échantillonnage direct de franges d'interférences ouvre de nombreuses perspectives, pour des applications allant de l'astrophysique aux télécoms. / This work presents the realization of a SWIFTS (Stationary Wave Integrated Fourier Transform Spectrometer) micro-spectrometer with SNSPD (Superconducting Nanowire Single Photon Detector) photon counters. The device features an integrated interferometer made of a SiN loop ridge-waveguide, with an array of 24 NbN-nanowire SNSPD underneath that samples at a 160nm period the interferogram of a laser light, at a wavelength centred on 1.55µm. The conception, preliminary studies of integrated optics and electronics, fabrication and characterization at 4.2K of the final device are described, in particular the observation of the detected signal modulation in the waveguide in agreement with the expected interference formation. The SWIFTS-SNSPD constitutes the first stand-alone, fully integrated superconducting optoelectronic device. Its unique capability of direct sampling of light interferogram opens numerous perspectives, with possible applications ranging from astrophysics to telecommunications.