We have previously demonstrated a method for achieving room-temperature, intraband, midinfrared (3-5 μm) absorption in CdSe colloidal quantum dotpoly[2-methoxy-5-(2′ -ethylhexyloxy)-1,4- phenylenevinylene] conducting polymer nanocomposites deposited on GaAs substrates. In this work, theoretical and experimental evidence are presented to further verify that the observed infrared sensitivity is due to intraband transitions. © 2008 American Institute of Physics.