Temporal chirpless near-field microscope

An imaging system with a single lens imposes a quadratic phase on the optical field. Usually, we can neglect it when measuring intensity, since our sensors are not sensitive to this phase. For certain signal processing applications we may need to remove this phase. In our lab, we develop temporal imaging systems which image signals in time, similar to a lens in space. Therefore, temporal imaging systems also exhibit quadratic phase on the output signal. To cancel this quadratic phase, we designed a double-lens microscopy system that enables chirpless temporal magnification of the input signal. It can be used for adjusting the temporal width of entangled photons – making them temporally indistinguishable. Or for measuring optical decaying signals in active-dispersive medium with complex β_2, (the temporal equivalence of spatial evanescent waves). This system also has a larger temporal aperture compared to a single time-lens, assuring no loss of frequencies at the output.