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Wu P.,Tianjin Key Laboratory of Film Electronic and Communication Devices | Ren G.-J.,Tianjin Key Laboratory of Film Electronic and Communication Devices | Yao J.-Q.,Institute of Laser and Opto electronics
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2014

The production of filter combined terahertz with photonic crystal fiber is rare. Fill the nematic liquid crystal in the photonic crystal fiber air hole, photonic crystal optical fiber transmission mechanism was tuned by changing the nature of the liquid crystal. Liquid crystal refractive index change with temperature, so that the defect mode frequency will move. Based on this mechanism, threshold switching or filter can be designed. For the terahertz sensing characteristics in this article, mode field area and sensitivity become small as the wavelength increases. © 2014, National Institute of Optoelectronics. All right reserved.

Cao X.-L.,Institute of Laser and Opto electronics | Yao J.-Q.,Institute of Laser and Opto electronics | Zhong K.,Institute of Laser and Opto electronics | Xu D-G.,Institute of Laser and Opto electronics | Xu D-G.,Key Laboratory of Opto electronics Information Technology
Optical Engineering | Year: 2013

Abstract. The intersubband absorptions between the conduction ground state and excited states in Al0.5Ga0.5As/GaAs/Al0.2Ga0.8As multiple asymmetric quantum well (AQW) have been investigated based on optical difference frequency in the 9 to 11 μm region. Under an intense resonant excitation from a dual-wavelength CO2 laser, the saturation intensity of intersubband absorption for pump waves is estimated to be 0.3 MW/cm2. As the well width variation, the position of absorption peak for pump waves and the absorption of terahertz (THz) wave by DFG show concomitant changes. For an AQW of 7 nm deep well-width and 27 nm total well-width, the maximum of absorption for the THz wave is 6.01×105 m-1 when the two pump wavelengths are 9.69 and 10.64 μm, respectively. These manipulative transitions in AQW can be applied to tunable optical semiconductor devices and implemented in THz wave devices to achieve additional functionalities. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE).

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