Real-time spectral analysis of ultrafast pulses using a free-space angular chirp-enhanced delay.

Frequency-to-time mapping is a powerful technique for observing ultrafast phenomena and nonrepetitive events in optics. However, many optical sources operate in wavelength regions, or at power levels, that are not compatible with standard frequency-to-time mapping implementations. The recently developed free-space angular chirp-enhanced delay (FACED) removes many of these limitations and offers a linear frequency-to-time mapping in any wavelength region where high-reflectivity mirrors and diffractive optics are available. In this work, we present a detailed formulation of the optical transfer function of a FACED device. Experimentally, we verify the properties of this transfer function and then present simple guidelines to guarantee the correct operation of a FACED frequency-to-time measurement. We also experimentally demonstrate the real-time spectral analysis of femtosecond and picosecond pulses using this system.