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Kerr nonlinear microcavities have garnered significant interest owing to their rich dynamics of nonlinear optical phenomena and compatibility with on-chip photonic integration. Recently, silicon carbide has emerged as a compelling platform due to its unique optical properties. In this study, we demonstrate Raman-assisted and Kerr optical frequency generation in a 4H-silicon carbide-on-insulator microresonator. By pumping the transverse electric (TE00) mode within the device, we observe a stimulated Raman scattering (SRS) Stokes with the Raman shift at approximately 775 cm-1, achieved with an on-chip power of 350 mW. Furthermore, by red-tuning the TE00 pump wavelength, we have achieved the coexistence of Raman and Kerr frequency combs. Using another device on the same chip with light variation of the taper we can observe the Raman and Kerr frequency combs within a spectral bandwidth ranging from ∼ 1440 to 1960 nm. The inclusion of the Raman-assisted comb extends the comb’s coverage into longer wavelength regimes, making it highly desirable for spectroscopy applications.

Porous Fe3O4/SnO2core/shell nanorods are successfully fabricated, in which the width and the length of the pores are 5−10 and 10−60 nm, respectively. We prepared 80 wt % of porous Fe3O4/SnO2core/shell nanorod-wax composites in order to measure their electromagnetic parameters. The measured results indicate that effective complementarities between the dielectric loss and the magnetic loss are realized over 2−18 GHz frequency range, suggesting the porous Fe3O4/SnO2core/shell nanorods have excellent electromagnetic wave absorption properties. The reflection loss was calculated in terms of the transmit-line theory. The absorption range under −20 dB is from 3.2 to 16.88 GHz for an absorber thickness of 2−5 mm. Moreover, the porous core/shell nanorods exhibit dual-frequency absorption characteristics and their maximum reflection loss reaches −27.38 dB at 16.72 GHz as the absorber thickness is 4 mm. The excellent microwave absorption properties of the porous Fe3O4/SnO2core/shell nanorods are attributed to effective complementarities between the dielectric loss and the magnetic loss and the special core−shell structures.