Investigation into nonlinear optical absorption property of CoSb3 skutterudite in the 2 μm spectral region. (September 2020)

• Record Type: Journal Article
• Authors: Lee, Jinho; Kim, Taeyoon; Lee, Ju Han
• Is Part Of: Optics & laser technology. Volume 129(2020)
• Publication Date: 2020-09
• Subjects: Nonlinear optical materials -- Saturable absorption -- Optical fiber lasers -- Mode-locking -- Skutterudite -- 2-μm wavelength; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2020.106274
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: Nonlinear absorption properties of CoSb3 was investigated at 2 μm wavelengths. The nonlinear absorption coefficient was measured at ~−90.5 × 10 4 cm/GW at 1900 nm. Using a CoSb3 SA, femtosecond mode-locking of a 1.9-μm fiber laser was achieved. Abstract: We report our recent investigation results on the nonlinear optical absorption property of CoSb3 skutterudite at 2-μm wavelengths. First, we conducted an open-aperture (OA) Z-scan measurement to figure out the nonlinear absorption coefficient (β) of CoSb3 skutterudite. The coefficient was estimated to be around −90.5 × 10 4 cm/GW at a wavelength of 1900 nm with the measurement. Next, in order to demonstrate the practical applicability of CoSb3 skutterudite in the 2-μm spectral region, a saturable absorber (SA) was implemented on a side-polished fiber platform by depositing a composite of CoSb3 and polyvinyl alcohol (PVA). The measured saturation power and modulation depth of the fabricated SA were ~21 W and ~10%, respectively. Using the prepared SA within a fiberized ring cavity, stable soliton pulses with a temporal width of ~838 fs could be produced at 1912.9 nm. The output pulses were almost transform-limited with a time-bandwidth product of ~0.32. The signal-to-noise ratio (SNR) was measured as ~72 dB at the fundamental frequency of ~16.93 MHz.