Strong TE-polarized intersubband absorption in InGaAs single-quantum-well waveguides

The authors report the first unambiguous demonstration that ternary quantum-well (QW) intersubband transitions are TE (transverse electric), as well as TM (transverse magnetic), active, a result that has significant implications for the applications of these transitions in a variety of infrared detector structures. Using a unique waveguide measurement geometry, Fourier transform infrared absorption measurements have been made on a number of lattice-matched In/sub 0.53/Ga/sub 0.47/As/In/sub 0.52/Al/sub 0.48/As and strained In/sub 0.7/G a/sub 0.3/As/AlAs/In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As single-QW waveguide heterostructures. These measurements show that both TE and TM polarized light can excite intersubband transitions.