Here is a useful story about a student’s search for the perfect resource and why the specific "better" version matters.
While many modern books focus on specific applications like quantum computing or silicon photonics, Loudon’s approach is foundational. It is widely considered "better" for three reasons: loudon quantum theory of light pdf better
Gerry and Knight is more introductory. If you find Loudon too difficult, start there, then move "up" to Loudon. Here is a useful story about a student’s
: This edition features a new introductory section that carefully addresses the conceptual challenges of defining a "photon". If you find Loudon too difficult, start there,
: Detailed chapters on chaotic light, intensity correlations, and the Brown-Twiss interferometer.
A better PDF also includes the and appendices . The third edition’s appendices on the dipole approximation and the fluctuation-dissipation theorem are often missing in bootleg scans.
The book is published by Oxford University Press and is available through various retailers: