AI Article Synopsis
- The study explores how terahertz waves can be converted to lower frequencies when passing through a GaAs waveguide, specifically at the temporal boundaries created by photoexcitation.
- The photoexcited waveguide facilitates the coupling of different electromagnetic modes, leading to a phenomenon known as frequency down-conversion, with efficient results confirmed by experimental data.
- The findings indicate that the direction of frequency conversion can be controlled by altering the polarization of the incoming waves, which could enhance terahertz communication systems by enabling efficient signal interconversion across various frequency channels.
Article Abstract
In this study, the frequency down-conversion of terahertz waves is analytically and experimentally demonstrated at the temporal boundaries within a GaAs waveguide. The temporal boundary is established by photoexciting the top surface of the waveguide, thereby instantaneously increasing its electrical conductivity. This photoexcited waveguide supports a transverse electromagnetic (TEM) mode with a frequency lower than those of the transverse magnetic (TM) modes present in the original waveguide. At the temporal boundary, the incident TM mode couples with the TEM mode, resulting in frequency down-conversion. Subtracting the propagation loss from the frequency-converted components indicates that the frequency conversion occurs with an efficiency consistent with the analytical predictions. The propagation loss is primarily due to ohmic loss, caused by the finite electrical conductivity of the photoexcited region. Given that the frequency of transverse electric modes is up-converted at the temporal boundary, our findings suggest that the direction of frequency conversion (upward or downward) can be controlled by manipulating the incident polarization. The polarization-dependent frequency conversion in waveguides holds significant potential for applications in devices designed for the interconversion of terahertz signals across various frequency channels. This capability is instrumental in the development of frequency-division-multiplexed terahertz wave communication systems, thereby enabling high data transfer rates.
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|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11501523 | PMC |
| http://dx.doi.org/10.1515/nanoph-2024-0010 | DOI Listing |
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Article Synopsis
- The study explores how terahertz waves can be converted to lower frequencies when passing through a GaAs waveguide, specifically at the temporal boundaries created by photoexcitation.
- The photoexcited waveguide facilitates the coupling of different electromagnetic modes, leading to a phenomenon known as frequency down-conversion, with efficient results confirmed by experimental data.
- The findings indicate that the direction of frequency conversion can be controlled by altering the polarization of the incoming waves, which could enhance terahertz communication systems by enabling efficient signal interconversion across various frequency channels.
Article Synopsis
- Thin film lithium niobate is a promising material for integrated photonics, known for its strong ability to convert wavelengths due to its second-order nonlinear properties.
- The team demonstrated simultaneous phase-matching for multiple wavelengths in coupled thin film lithium niobate waveguides without needing a poling technique, using modal phase-matching.
- They showed that the phase-matching wavelengths can be adjusted by changing the gap between waveguides, paving the way for efficient nonlinear optical processes in nanophotonics and quantum optics.
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