NNSE618-L16-intraband-absorption

NNSE618-L16-intraband-absorption - NNSE 618 Lecture #16 1...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: NNSE 618 Lecture #16 1 Lecture contents • Selection rules for interband transitions • Intraband transitions – Free carriers – Shallow impurities – Optical phonons – Polaritons NNSE 618 Lecture #16 2 Electric field modulation of transmission spectra of 100 A GaAs/AlGaAs QW at two polarizations Modulation of intersubband transitions in quantum wells • Absorption edge red-shifts with electric field • Exciton absorption strength reduces with field because the electron and hole wavefunctions are separated by electric field • Polarization rules apply due to symmetry of electron-radiation matrix elements From Miller, 1986 f i f er i p A mc e H QW plane E QW plane E HH CB LH CB LH CB NNSE 618 Lecture #16 3 Selection rules • We have seen that interaction of oscillating electric field with band states is proportional to the matrix element: • We can consider known symmetries of Bloch wavefunctions at the band extrema to find out when this matrix element is zero are non-zero f i f i f er i p p A mc e H NNSE 618 Lecture #16 4 Selection rules + polarization • Matrix elements for the band-to-band transitions: • These elements are zero: •...
View Full Document

This note was uploaded on 11/07/2011 for the course NNSE 618 taught by Professor Sergeoktyabrsky during the Spring '11 term at SUNY Albany.

Page1 / 11

NNSE618-L16-intraband-absorption - NNSE 618 Lecture #16 1...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online