Abstract: An aspect of the present disclosure is related to a method for measuring and controlling linear chirp level of ultrafast laser pulse. The method includes steps as follows. A carrier-envelope phase-chirp (CEP-chirp) relation which serve as a chirp monitor is extracted, in which the CEP-chirp relation is generated from an ultrafast laser pulse. A linear chirp level of a target pulse is measured in response to the CEP-chirp relation. According to the measuring with respect to the linear chirp level of the target pulse, a dispersion element which the ultrafast laser pulse passes through is varied to control and stabilize the linear chirp level of the target pulse.

Abstract: An aspect of the present disclosure is related to a method for measuring and controlling linear chirp level of ultrafast laser pulse. The method includes steps as follows. A carrier-envelope phase-chirp (CEP-chirp) relation which serve as a chirp monitor is extracted, in which the CEP-chirp relation is generated from an ultrafast laser pulse. A linear chirp level of a target pulse is measured in response to the CEP-chirp relation. According to the measuring with respect to the linear chirp level of the target pulse, a dispersion element which the ultrafast laser pulse passes through is varied to control and stabilize the linear chirp level of the target pulse.

Abstract: A reflection-mode waveplate for operation in the terahertz region by shifting the phase between two perpendicular polarization components of the light wave, comprising a ground plane; an array of polygonal unit cells; the polygonal unit cells comprising a polymer positioned between the ground plane and the exterior of the array of polygonal patches.

Abstract: A reflection-mode waveplate for operation in the terahertz region by shifting the phase between two perpendicular polarization components of the light wave, comprising a ground plane; an array of polygonal unit cells; the polygonal unit cells comprising a polymer positioned between the ground plane and the exterior of the array of polygonal patches.

Abstract: Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.

Abstract: Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.