Photonics

Photonics

Plane light sources are transmitted in a vacuum

    • 2212296
      Subscriber

      Hi everyone, I ran a small simulation test. The substrate is aluminum oxide, rectangular in shape and 500um in thickness (-500, 0). The light source selects a plane beam with a wavelength of 40um, and the position is 20um (20) higher than the substrate. The monitor selects the frequency domain power monitor, which is located at (-550) um. After running the simulation, I found that the monitor power is 0.

      I think something happens, like the absorption of light by aluminum oxide. So I set the substrate material to etch and the result is still 0. This is not the same as what I expected. Why can't the light source travel a long distance without a medium? Thank you very much for your reply.

    • 2212296
      Subscriber

    • 2212296
      Subscriber

    • 2212296
      Subscriber

      In addition, the background refractive index of the FDTD simulation region is 1

    • Moshe
      Subscriber

      Hi,

      I suggest to check the "simulation time" in the FDTD.

      My guess is that your simulation time ended before the wave reached the field monitor.

       

      Best regards.

      • 2212296
        Subscriber

        Thanks for your suggestion, I will try it.

    • Guilin Sun
      Ansys Employee

      Thank you @Moshe ! this is the first thing to check with a time monitor and see if the pulse has reached there, and have a series of pulses due to this F-B cavity.

      Please make sure you are simulating a cavity.

      • 2212296
        Subscriber

        Sorry, I'm not very familiar with time monitoring. I may need an example to help me figure out how to set the simulation time. In addition, my main working range is in the terahertz band. Thanks again.

    • Guilin Sun
      Ansys Employee

      terahertz band will definitely need much longer simulaiton time since the default is for optical frequency. For cavity, you can think the simulation needs 100 times of the light propagation from source to monitor due to multiple reflections, and let the autoshutoff min to terminate the simulation.

      You can simply add a time monitor at the exit side. After simulation terminates, you can check the time signal with visualier: https://optics.ansys.com/hc/en-us/articles/360037222234-Using-the-data-visualizer-and-figure-windows

      Another method is to check the progress percentage. If it terminates at 100% with the default autoshutoff min, it indicates the simulation time is not long enough.

       

      There are some online videos in the EDU course, or in youtube that you can search and watch.

       

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