Sökning: "optical mixers"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden optical mixers.

1. 1. NbN Hot Electron Bolometric Mixers for a Quasi--Optical THz Receiver

   Författare :Matthias Kroug; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bolometric mixer; superconducting NbN; heterodyne detection; hot electron effect; quasi-optical;

   Sammanfattning : Experimental work on the development of a quasi-optical heterodyne receiver for the THz frequency range is reported. The mixing device is a superconducting hot electron bolometer (HEB) made from ultrathin, d = 3 - 5 nm, niobium nitride (NbN) films. LÄS MER

3. 2. Antenna Integrated Superconducting Mixers

   Författare :Hans Ekström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tapered slotline antenna; mixer; double dipole antenna; superconducting; hot electron; receiver; Niobium; bolometer; trilayer junction; edge junction; Niobium Nitride; SIS;

   Sammanfattning : This thesis investigates the prospects of some different superconducting mixers integrated with planar antennas for the millimeter and submillimeter regime. Two kinds of Superconductor/Insulator/Superconductor (SIS) tunnel junctions for use in mixers have been fabricated; Nb/PbBi edge junctions and Nb trilayer junctions. LÄS MER

4. 3. Design and characterisation of terahertz Schottky diode harmonic mixers

   Författare :Divya Jayasankar; RISE Research Institutes of Sweden; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Schottky diodes; Phase locking; Harmonic mixers; Heterodyne receivers; Terahertz electronics; Frequency stabilisation; Frequency converters;

   Sammanfattning : Efficient, compact, and reliable terahertz frequency converters preferably operating at ambient temperature are crucial for stabilising far-infrared optical sources. This thesis focuses on the design and characterisation of terahertz Schottky diode harmonic mixers for frequency stabilisation of quantum-cascade lasers. LÄS MER

5. 4. Photonic terahertz-wave generation, radiation and quasioptical integration

   Författare :Biddut Kumar Banik; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor device modelling; semiconductor diodes; III-V semiconductors; Catadioptric lens; imaging; dipole antennas; slot antennas; lens antennas; semiconductor heterojunctions; dielectric loaded antennas; optical mixers; photomixers; near-field imaging; computer aided engineering; indium compounds; millimetre wave imaging; near-field optics; submillimeter wave generation; photodiodes; terahertz sources; millimetre wave generation; submillimetre wave integrated circuits; microwave imaging; uni-travelling-carrier photodiodes;

   Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER

7. 5. Characterisation and Modelling of Graphene FETs for Terahertz Mixers and Detectors

   Författare :MICHAEL ANDERSSON; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; graphene; millimetre and submillimetre waves; power detectors; nonlinear device modelling; microwave amplifiers; nanofabrication; integrated circuits; noise modelling; Field-effect transistors FETs ; terahertz detectors; Volterra; subharmonic resistive mixers;

   Sammanfattning : Graphene is a two-dimensional sheet of carbon atoms with numerous envisaged applications owing to its exciting properties. In particular, ultrahigh-speed graphene field effect transistors (GFETs) are possible due to the unprecedented carrier velocities in ideal graphene. LÄS MER