Ultra-high-finesse IV-VI microcavities for the midinfrared

IV-VI semiconductor-based midinfrared microcavities with very high-quality factors were grown by molecular-beam epitaxy. The structures consist of PbT e/EuTe Bragg mirrors with three to five layer pairs rendering reflectivitie s in excess of 99.7%. The PbTe resonator layer between the reflectors has a n optical length of lambda/2, which yields a first-order cavity. The transm ission spectra of the microcavities show a very narrow Lorentzian-shaped Fa bry-Perot resonance at 1877 cm(-1) (lambda=5.32 mu m) with a full width at half maximum of 0.63 cm(-1) 78 mu eV. This corresponds to an ultrahigh effe ctive cavity finesse of 1700. (C) 1999 American Institute of Physics. [S000 3-6951(99)01235-8].