Figure 3

Second-harmonic generation (SHG) from the Ba₂TiSi₂O₈ (BTS) glass-ceramic (GC). (a) Spectrum of the upconverted luminescence from the focal area upon irradiation using an 800 nm fs laser. The insets show the power dependence of the spectral intensity of the SHG signal (top) and the charge coupled device (CCD)-captured images for the emission spot from the front and side surfaces of the GC (bottom). (b) Temporal intensity profile of the SHG radiation. (c) Spectra collected from the focal area upon excitation at 900, 1080 and 1230 nm. The inset images shows clear blue, green and red light radiated from the focal area. (d) The corresponding CIE chromaticity diagram showing the color coordinates that were calculated from the spectra shown in c. (e) Simulated electric field E (upper panel) and E² (middle panel) intensity distribution along the light path and E² (bottom panel) intensity distribution in the presence of attenuation (assuming a nonlinear absorption coefficient of 0.000005 cm⁻¹). The simulation was conducted by assuming a Gaussian beam profile. The red, green and blue curves represent the boundaries where the intensity is enhanced 10⁵, 10⁷ and 10⁹ times, respectively.