Single-beam homodyne SPIDER for multiphoton microscopy

Compression of fiber supercontinuum pulses to the Fourier-limit in a high-numerical-aperture focus

A multiphoton intrapulse interference phase scan (MIIPS) adaptively and automatically compensates the combined phase distortion from a fiber supercontinuum source, a spatial light modulator pulse shaper, and a high-NA microscope objective, allowing Fourier-transform-limited compression of the supercontinuum pulses at the focus of the objective. A second-harmonic-generation-based method is employed to independently validate the transform-limited compression. The compressed pulses at the focus of the objective have a tunable duration of 10.8-38.9 fs (FWHM), a central wavelength of ~1020 nm, an average power of 18-70 mW, and a repetition rate of 76 MHz, permitting the application of this source to nonlinear optical microscopy and coherently controlled microspectroscopy.

Application of single-beam homodyne SPIDER for the control of complex spectral phase profiles

We investigate the range of application of single-beam homodyne spectral phase interferometry for direct electric field reconstruction (SPIDER) for multiphoton microscopy. Simulations and experimental studies performed on model spectral phase profiles show that the phase reconstruction technique used in this method makes the phase retrieval quality highly sensitive to the complexity of the profile. In addition, we show that the use of iterative processes is likely to deteriorate the phase retrieval quality, especially for strongly varying phase profiles. These effects are illustrated and quantified for sinusoidal and quadratic spectral phase profiles.