Showing papers by "Wei Fang published in 2013"
TL;DR: In this paper, a whispering gallery mode microlaser was used to construct freestanding microdisks supported by thin pillars by femtosecond laser ablation of the glass substrate immersed in water, followed by CO2 laser annealing.
Abstract: We report on fabrication of whispering-gallery-mode microlasers in a Nd:glass chip by femtosecond laser three-dimensional micromachining. The main fabrication procedures include the fabrication of freestanding microdisks supported by thin pillars by femtosecond laser ablation of the glass substrate immersed in water, followed by CO2 laser annealing for surface smoothing. The quality (Q) factor of the fabricated microcavity is measured to be 1.065×10(6). Lasing is observed at a pump threshold as low as ~69 μW at room temperature with a continuous-wave laser diode operating at 780 nm. This technique allows for fabrication of microcavities of high Q factors in various dielectric materials, such as glasses and crystals.
48 citations
TL;DR: Multicolour lasing with wavelength varying from 578 nm to 640 nm is realized from a single bandgap-graded CdSSe alloy nanoribbon, by selecting the excited spot at room temperature by increasing the excitation area.
Abstract: Multicolour lasing with wavelength varying from 578 nm to 640 nm is realized from a single bandgap-graded CdSSe alloy nanoribbon, by selecting the excited spot at room temperature Though reabsorption is a serious problem to achieve lasing at short wavelength, multiple scatters on the nanoribbon form localized cavities, and thus lasing at different wavelengths is realized By increasing the excitation area, multicolour lasing from the same nanoribbon is also observed simultaneously
35 citations
TL;DR: In this article, a polymer micro/nanofiber Bragg gratings (MNFBGs) are fabricated with a ~551nm grating period and a grating depth >;10 dB around 1.5μm wavelength.
Abstract: By using a simple and low-cost nanoimprinting technique, polymer micro/nanofiber Bragg gratings (MNFBGs) are fabricated with a ~551-nm grating period and a grating depth >;10 dB around 1.5-μm wavelength. As-fabricated MNFBGs also show high compactness to optical fiber systems and large dynamic range. Using a 2.5-μm-wide and 1.4-μm-thick MNFBG, we demonstrate strain sensing with a high sensitivity of -2.5 pm/μe.
31 citations
TL;DR: Investigations indicate the MNF is a promising candidate for developing the sources of nonclassical light and the spectral property of photon pairs can be used to noninvasively test the diameter and homogeneity of the M NF.
Abstract: We study the generation of correlated photon pairs via spontaneous four wave mixing in a 15 cm long micro/nano-fiber (MNF). The MNF is properly fabricated to satisfy the phase matching condition for generating the signal and idler photon pairs at the wavelengths of about 1310 and 851 nm, respectively. Photon counting measurements yield a coincidence-to-accidental ratio of 530 for a photon production rate of about 0.002 (0.0005) per pulse in the signal (idler) band. We also analyze the spectral information of the signal photons originated from the spontaneous four wave mixing and Raman scattering. In addition to discovering some unique feature of Raman scattering, we find the bandwidth of the individual signal photons is much greater than the calculated value for the MNF with homogeneous structure. Our investigations indicate the MNF is a promising candidate for developing the sources of nonclassical light and the spectral property of photon pairs can be used to non-invasively test the diameter and homogeneity of the MNF.
27 citations
TL;DR: In this paper, a 15 cm long micro/nano-fiber (MNF) was fabricated to satisfy the phase-matching condition for generating the signal and idler photon pairs at wavelengths of about 1310 and 851 nm, respectively.
Abstract: We study the generation of correlated photon pairs via spontaneous four-wave mixing (SFWM) in a 15 cm long micro/nano-fiber (MNF). The MNF is properly fabricated to satisfy the phase-matching condition for generating the signal and idler photon pairs at wavelengths of about 1310 and 851 nm, respectively. Photon-counting measurements yield a coincidence-to-accidental ratio of 530 for a photon production rate of about 0.002 (0.0005) per pulse in the signal (idler) band. We also analyze the spectral information of the signal photons originating from SFWM and Raman scattering (RS). In addition to discovering some unique features of RS, we find the bandwidth of the individual signal photons is much greater than the calculated value for the MNF with homogeneous structure. Our investigations indicate the MNF is a promising candidate for developing the sources of nonclassical light and the spectral property of photon pairs can be used to noninvasively test the diameter and homogeneity of the MNF.
26 citations
09 Jun 2013
TL;DR: In this article, the authors report efficient transverse sum-frequency generation in single semiconductor nanowires with low power operation, which may serve as broadband tunable coherent light source for potential application in physics, chemistry, materials science and biology.
Abstract: Here we report efficient transverse sum-frequency generation in single semiconductor nanowires with low-power operation, which may serve as broadband tunable coherent light source for potential application in physics, chemistry, materials science and biology.
1 citations