1% rms amplitude noise from a 30 fs continuum based source tunable from 800 to 1250 nm.

We present amplitude noise characterization of a low-cost continuum source tunable from 800 to 1250 nm, with the pulse duration of 30 fs, and average output power up to 140 mW at 80 MHz pulse repetition rate. The system is based on a SESAM-modelocked, solid-state Yb tungstate laser plus spectral broadening via a microstructured fiber followed by pulse compression with a simple prism compressor. The measured RMS amplitude noise of 1.2 to 2.5% in the whole tunable range is comparable to the modelocked oscillators. Additionally, we show an excellent agreement between simulated and the experimentally measured spectra.

Two-photon fluorescence imaging with 30 fs laser system tunable around 1 micron.

We developed a low-cost, low-noise, tunable, high-peak-power, ultrafast laser system based on a SESAM-modelocked, solid-state Yb tungstate laser plus spectral broadening via a microstructured fiber followed by pulse compression. The spectral selection, tuning, and pulse compression are performed with a simple prism compressor. The output pulses are tunable from 800 to 1250 nm, with the pulse duration down to 25 fs, and average output power up to 150 mW, at 80 MHz pulse repetition rate. We introduce the figure of merit (FOM) for the two-photon and multi-photon imaging (or other nonlinear processes), which is a useful guideline in discussions and for designing the lasers for an improved microscopy signal. Using a 40 MHz pulse repetition rate laser system, with twice lower FOM, we obtained high signal-to-noise ratio two-photon fluorescence images with or without averaging, of mouse intestine section and zebra fish embryo. The obtained images demonstrate that the developed system is capable of nonlinear (TPE, SHG) imaging in a multimodal operation. The system could be potentially used in a variety of other techniques including, THG, CARS and applications such as nanosurgery.