Search

We have studied guiding performance of 2-MeV proton implanted diamond waveguides as a function of implantation fluence and annealing temperature. Raman spectra show that the change in refractive index (Δ n ˜) cannot be ascribed to any single defect. Instead, the normalized intensity of the 1332 cm−1 Raman line (I Raman) has been adopted as a generic parameter to quantify the structural damage caused by implantation. I Raman is experimentally shown to be an indicator of guiding performance. Of all the fabrication conditions, I Raman = 0. 27 in the guiding region produces the largest transmission and is achieved by implantation at fluence of 1 × 1016 cm−2 followed by annealing at 600℃. Experimental observations have been supported by the reconstruction of mode profiles with finite element simulation using I Raman. A single linear relationship of Δ n ˜ = (6. 1 + 8. 5 i) × 10−3 ⋅ (1 − I Raman) is employed to simulate all of the experimental mode profiles. Our use of proton beam writing and the measured I Raman is a potential technique to design and manufacture light-guiding structures directly in bulk single crystal diamond. Image 1 [ABSTRACT FROM AUTHOR]

Herein, finite‐element analysis is used to optimize the performance of mid‐infrared (MIR) (7.7–13.7 μm) waveguides by selecting optimal waveguide and substrate materials, waveguide size, and boundary field. The results show that a diamond waveguide has a substantially higher sensitivity than Si‐ or Ge‐based waveguides owing to its higher boundary evanescent field at the same depth. Furthermore, it is found that AlN substrates have better optical stabilities than SiO2 and Si3N4 substrates, because AlN substrates do not have apparent absorption characteristics in the MIR range (7.7–13.7 μm). Geometry of diamond waveguide on AlN substrate is optimized, and a section length of 45 μm is chosen for optimal signal transmission quality. The calculations of the infrared attenuated total reflection (ATR) of the diamond waveguide applied to water, alcohol, and diisopropyl methyl phosphate are highly consistent with the actual infrared absorption spectrum. This proves the feasibility of applying AlN/diamond waveguides in MIR ATR detection, which is of great significance for the preparation of high‐sensitivity MIR detectors. [ABSTRACT FROM AUTHOR]