Microcrystalline Diamond Powders As Promising Objects for Generation of Multifrequency Stimulated Raman Scattering

Abstract

Regular trends of Raman scattering in microcrystalline diamond powders as a function of size of the diamond microcavities are investigated in the range of the latter between 1 to 600 μm. The observed effect of anomalously high intensity of spontaneous Raman scattering is attributed to “trapping” of electromagnetic radiation with a wavelength shorter than the size of the diamond microcrystals in diamond microcavities. The electromagnetic energy density for the driving and secondary radiation increases as a result of photon “trapping” in the diamond microcavities. A high Q factor of the fundamental optical mode in the vibrational sp-ectrum of diamond and anomalous increase in the Raman scattering intensity in diamond microcavities pave the way for observation of the low-threshold multifrequency Raman scattering in microcrystalline diamond powders. Using the radiation of a pulsed solid state YAG:Nd³⁺ laser at the fundamental wavelength (λ = 1064 nm) and its optical harmonics (λ = 532, 355, 266 nm) as sources of driving radiation opens up a possibility for creation of an array of equidistant (with respect to frequency shift) laser sources with wavelengths extending from the ultraviolet to the terahertz range promising for investigation of biological and medical objects.