title: Resonant second-order nonlinear optical processes in quantum cascade lasers.
abstract: We demonstrate an efficient intracavity nonlinear interaction of laser modes in a specially adapted quantum cascade laser. A two-wavelength quantum cascade laser structure emitting at wavelengths of 7.1 and 9.5 micrometer included cascaded resonant optical intersubband transitions in an intracavity configuration leading to resonantly enhanced sum-frequency and second-harmonic generation at wavelengths of 4.1, 3.6, and 4.7 micrometer respectively. Laser peak optical powers of 60 and 80 mW resulted in 30 nW of sum-frequency signal and 10-15 nW of second-harmonic signal, both in good agreement with theoretical calculations.
authors.affiliation: Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974, USA.
authors.forename: Nina
authors.initials: N
authors.lastname: Owschimikow
authors.forename: Claire
authors.initials: C
authors.lastname: Gmachl
authors.forename: Alexey
authors.initials: A
authors.lastname: Belyanin
authors.forename: Vitaly
authors.initials: V
authors.lastname: Kocharovsky
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Sivco
authors.forename: Raffaele
authors.initials: R
authors.lastname: Colombelli
authors.forename: Federico
authors.initials: F
authors.lastname: Capasso
authors.forename: Alfred Y
authors.initials: AY
authors.lastname: Cho