Four-wave mixing fast wavelength sweeping FDML laser with kW peak power at 900 nm and 1300 nm

Abstract

High power fast wavelength sweeping fiber lasers can be used in many ways, e.g. in nonlinear imaging methods like stimulated Raman [1] and spectro-temporal laser imaging by diffractive excitation (SLIDE) two-photon microscopy [2]. In the 900 nm region fluorescent proteins especially in brain activity measurements are of high interest [3], [4]. Unfortunately, at 900 nm and 1300 nm no appropriate fiber gain media are present and other ways of achieving high peak power, like four-wave mixing (FWM), are needed [5]. This FWM approach is used here to shift the laser power of our 1064 nm master oscillator power amplifier (MOPA) fiber laser to the 1300 nm of a Fourier Domain Mode locked (FDML) laser [6], while generating a 900 nm FWM wavelength tuneable pulsed output (Figure 1, left side). With this, 2.5 kW peak power over a 54 nm span and 70 pm spectral width at 900 nm and 1.4 kW peak power over a 105 nm span at 1300 nm is possible.