Physics
The Feynman Lectures on Physics
Electricity and Magnetism - Purcell - pdf
Cohen-Tannoudji, Diu and Laloë - Quantum Mechanics (vol. I, II and III, 2nd ed.) : Claude Cohen-Tannoudji, Bernard Diu and Franck Laloë : Free Download, Borrow, and Streaming : Internet Archive
DSP
Signals & systems : Oppenheim, Alan V., 1937- : Free Download, Borrow, and Streaming : Internet Archive
Courses
Signals and systems
Video Lectures | Signals and Systems | Electrical Engineering and Computer Science | MIT OpenCourseWare
Lecture 7: Discrete Approximation of Continuous-Time Systems | Signals and Systems | Electrical Engineering and Computer Science | MIT OpenCourseWare
Medical imaging systems
Fessler: UMich EECS 516 Homepage
Electronics
lcamtuf
The 101 of analog signal filtering - lcamtuf’s thing
Advanced technologies (e.g., applied physics)
Microwave-optics quantum frequency conversion and optically heralded microwave photons | Stanford Digital Repository
Etc
Scaling and networking a modular photonic quantum computer | Nature