Detection of Light

Detection of Light - Spring Semester 2020

Location & Time

The lectures take place in room HL 414 in the Huygens building, on Fridays from 14:15 - 16:00 hr (unless otherwise noted - check schedule below).


Course level is 500. The course language is English.

Course concept and content

Detectors are the crucial link between the astronomical target and the observer. As astronomers are aiming at fainter and fainter objects the quality and calibration of the detector systems have become increasingly important. The main goal of this course is to provide an overview of the various physical principles and techniques to detect electromagnetic radiation, from the UV to the sub-millimeter.

The course is split in two parts:

'Part A' (3 ECTS) is aimed at the observational astronomer and provides an overview of common  detector technologies and their operation.  Course topics are intrinsic and extrinsic photo-conductors, photodiodes and other junction-based detectors, detector arrays, bolometers, coherent receivers, and submillimeter- and millimeterwave heterodyne receivers. The course will not only provide the physical background of the various detector technologies but also cover practical aspects, which are of general interest to the observer, such as cosmetic quality and detector artifacts, linearity and dynamical range, spectral response and bandwidth, quantum efficiency and noise.

For students of Astronomy (Research) following DTL, part A is mandatory, part B is optional; for Instrumentation students, both parts are mandatory. Students who want to get credits for 'Part B' must have followed 'Part A' before.

Credits and grading

'Part A' and 'Part B' each count ECTS (3+3).

The grade for 'Part A' is based to 80% on the written exam and to 20% on the mandatory homeworks. There are 8 sets of homeworks, which will be distributed after each lecture via the course website, and which shall be handed-in, on paper, at the start of the subsequent lecture (usually one week later). The exam is on Friday, 17 April 2020, 14:15 - 18:00 hr. It is a written, "closed book" exam. Pocket calculators are required at the exam.

In order to get the credits for 'Part B', one has to attend the lectures of 'Part B', as well as write a report, which is mainly a literature study on a topic which is related to one of the guest lectures.  The report has to be written within six weeks and will not receive a numerical grade but receive an O/V/G "grade".


The course will be heavily based on the book Detection of Light - from the Ultraviolet to the Submillimeter, by George Rieke, 2nd Edition, 2003, Cambridge University Press, ISBN 0-521-01710-6, paperback ~90 €. It is recommended that students get their own copy of this book.

Recommended for further reading are:

Schedule 'Part A'



f2f Organization & Refresher of Solid State Physics

General: grading, exercises, book, nature of light, EM spectrum, technology, photographic plate, overview of detectors principles and types; solid state physics: atomic energy levels, crystal: bands, conductors and semi-condd., k-vector, Fermi energy

  no lecture


f2f Intrinsic Photoconductors & Noise

general principle, box diagram, conductivity, mobility, tau, gain, quantum efficiency and responsivity; intro noise: poisson & Gaussian & 1/f noise; detector noise: Johnson, kTC, 1/f, BLIP

f2f Extrinsic Photoconductors

energy bands, doping, wavelength ranges, limitations, drawbacks and comparisons; BIB detectors, photodiodes, avalanche diodes

4 6-Mar-20 f2f IR Arrays & CCDs IR arrays: principle, construction, readout electronics; CCDs: principle, back/front illuminated, thinned, readout, CTE, CT architectures, variants Homework
  Covid-19 pause    
  Covid-19 pause    
online Operations and Artifacts

Readout schemes: SUR, Fowler, linearity & dynamic range, data rates; cryogenics

online Operations / Bolometers

(Buffer slot -- will be filled)

  10-Apr-20   no lecture Good Friday  
17-Apr-20 online Bolometers

Basic operation, time constants, superconducting, edged; comparison: responsivity, noise, NEP

8 24-Apr-20  online Heterodyne Detectors general principle, IF, mixing, sidebands, bandwidth, components (HEB, SIS); performance: throughput, S/N, noise and antenna temperature, comparison coherent-incoherent detectors Homework
  30-Apr-20 online oral exams  individual time slots still TBD  
  1-May-20 online oral exams individual time slots still TBD  


Program 'Part B'

The guest lectures for 'Part B' run from 8 May through 19 June.  There will be 6 lectures (on May 22nd, the university will be closed).

Date Speaker Affiliation Topic
8-May-20 Liz George ESO Development, characterization and operation of detectors for astronomy
15-May-20 Jochem Baselmans SRON/TU Delft Kinetic Inductance detectors for imaging and spectroscopy from optical to Terahertz astronomy
22-May-20 University closed
29-May-20 Akira Endo TU Delft On-chip spectrometers
5-Jun-20 Linda Höeglund IRnova QWIP detectors
12-Jun-20 Pourya Khosropanah SRON TES and applications
19-Jun-20 Alessandra Menicucci TU Delft Space radiation environment and its effect on detectors