• Development of coherent tunable source in 2–16 𝜇m region using nonlinear frequency mixing processes

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      https://www.ias.ac.in/article/fulltext/pram/082/01/0029-0038

    • Keywords

       

      Nonlinear frequency conversion; infrared radiation; nonlinear materials

    • Abstract

       

      A very convenient way to obtain widely tunable source of coherent radiation in the infrared region is through nonlinear frequency mixing processes like second harmonic generation (SHG), difference-frequency mixing (DFM) or optical parametric oscillation (OPO). Using commonly available Nd:YAG laser and its harmonic pumped dye laser radiation as parent beams, we have been able to generate coherent tunable infrared radiation (IR) in 2–16 𝜇m region using different nonlinear crystals by DFM and OPO. We have also generated such IR source in the 4–5 𝜇m region through SHG of CO2 laser in different infrared crystals. In the process we have characterized a large number of nonlinear crystals like different borate group of crystals, KTP, KTA, LiIO3, MgO:LiNbO3, GaSe, AgGaSe2, ZnGeP2, AgGa$_{1−x}$In$_x$Se2, HgGa2S$_4$ etc. To improve the conversion efficiencies of such frequency conversion processes, we have developed some novel schemes, like multipass configuration (MC) and positive optical feedback (POF). The significance of the obtained results lies in the fact that to get the same conversion in SHG or DFM, one now requires fundamental input radiation with much lower intensity.

    • Author Affiliations

       

      Udit Chatterjee1

      1. Laser Laboratory, Physics Department, Burdwan University, Burdwan 713 104, India
    • Dates

       
  • Pramana – Journal of Physics | News

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