Demonstration of minute continuous-wave triggered supercontinuum generation at 1 µm for high-speed biophotonic applications

Abstract

Ultra-broadband supercontinuum (SC) at 1-μm wavelength is regarded as diagnostics window in bio-photonics due to its large penetration depth in tissues and less Rayleigh scattering. Dispersive Fourier transform (DFT) is an important technique to realize the high-speed, ultra-fast and high-throughput spectroscopy. Thus, a stable light source with good temporal stability plays an important role in the bio-imaging and spectroscopy applications. We here demonstrate stabilized and enhanced SC generation at 1 μm by a minute continuous-wave (CW) triggering scheme. By introducing a weak CW (200,000 times weaker than the pump), a significant broadening in the SC bandwidth and an improvement in the temporal stability can be obtained. Over 8 dB gain is achieved in both blue and red edges and the SC spectrum can span from 900 nm to over 1300 nm with the CW trigger. We present the CW-triggered SC capability of enabling highspeed spectroscopy based on DFT at 1 μm. In regards to the performance of DFT, the wavelength-time mapping fluctuation reduced by 50% which is an indication of the improvement of the temporal stability. This triggering scheme allows, for the first time, 1-μm DFT at a spectral acquisition rate of 20 MHz with good temporal stability - paving the way toward realizing practical real-time, ultrafast biomedical spectroscopy and imaging.