Incoherent Photon Detection Bolometric Photon Counting Integrating Radio Telescopes Typical Designs Heterodyne Receivers Janskys First Radio Telescope 1933 Grote Reber 1937 Radio Telescope ID: 720338
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Slide1
Detection Methods
Coherent
↔
Incoherent
Photon Detection
↔
Bolometric
Photon Counting
↔ IntegratingSlide2
Radio Telescopes
Typical Designs
Heterodyne ReceiversSlide3
Jansky’s First Radio Telescope
1933Slide4
Grote Reber: 1937 Radio TelescopeSlide5
The Arecibo Radio TelescopeSlide6Slide7Slide8Slide9Slide10
Heterodyne Receivers
Mix signal and local oscillator
Mixed signal contains
“intermediate frequency”
f_signal – f_local
but also the sum of the frequenciesSlide11
Heterodyne Signal DetectionSlide12Slide13Slide14Slide15Slide16
MM and Sub-MM Telescopes
Use both coherent and incoherent detection
Heterodyne receivers for emission-lines
Mostly bolometers for continuumSlide17
Millimeter Valley on Mauna KeaSlide18Slide19
NGC 6334Slide20Slide21
SMA ReceiversSlide22
Bolometers
Absorb and thermalize photons
Measure temperature change
Balance between heating and cooling results in long time constants
Typically used in chopped operationSlide23Slide24Slide25Slide26Slide27Slide28Slide29
Transition Edge Sensors: Extreme sensitivity to small temperature changes allows to build very sensitive bolometer arraysSlide30Slide31
Photocathods
The photoelectric effect
Quantum nature of light
Photomultipliers, channel plates …Slide32Slide33Slide34Slide35Slide36Slide37Slide38
Photocathod Devices
Cathods
Photomultiplier
Image intensifiers
Microchannel platesSlide39Slide40Slide41Slide42Slide43
Physics of Semiconductors
Basic Quantum Physics
Solids
Semiconductors
PN JunctionsSlide44Slide45Slide46Slide47Slide48Slide49Slide50Slide51
Semiconductors
Conduction in semiconductors
DopingSlide52Slide53Slide54Slide55Slide56Slide57Slide58Slide59Slide60
PN Junctions
Formation of pn junction
Rectifying properties
Charge separating propertiesSlide61Slide62Slide63Slide64Slide65Slide66Slide67Slide68Slide69Slide70
Electronics
PN junctions and photodiodes
Field Effect transistors
Logic devices
Analog switches
Operational amplifiersA practical exampleSlide71
Field Effect Transistor
Junction FET (JFET)
Metal-Oxide-Semiconductor FET (MOSFET)
CMOS circuits (Complementary Oxide Semiconductor)Slide72Slide73Slide74Slide75Slide76Slide77Slide78Slide79Slide80Slide81
Fabrication of Integrated Circuits
Doping
Depositing metal
Growing oxides (as isolators)
All controlled by photoresist maskingSlide82
HAWAII-2: Photolithographically Abut 4 CMOS Reticles to Produce Each 2048
2
ROIC
Twelve 2048
2
ROICs per 8” Wafer
2048
2
Readout Provides Low Read Noise for Visible and MWIRSlide83
3-D Barrier to Prevent Glow from Reaching the DetectorSlide84Slide85Slide86Slide87Slide88