Spectral restoration for femtosecond spectral interferometry with attosecond accuracy

Lightweight hollow rooftop mirrors for stabilized interferometry

“…A piezoelectric transducer was attached to the back of HRM to actively stabilize the interferometer displacement using feedback from a polarized continuous wave 632.8 nm wavelength HeNe laser. 3,32 Acceleration of the retroreflector during active interferometer stabilization with the piezoelectric transducer is up to ∼10 −2 g (rms) in a 50 Hz to 3 kHz frequency range. Interferometer displacement was independently monitored outside of the feedback loop using a polarized continuous wave 594.1 nm wavelength HeNe laser.…”

“…Interferometer displacement was independently monitored outside of the feedback loop using a polarized continuous wave 594.1 nm wavelength HeNe laser. 3 The yellow and red beams were copropagating; the HRMs allowed femtosecond laser beams to be stacked above them inside the interferometer. A displacement stability of AE0.8 nm rms was measured over 0.1 Hz to 10 kHz, demonstrating the structural rigidity of the HRM required for use in actively stabilizing an interferometer.…”

“…Retroreflectors have found many precision metrology uses, from measurements of distances 1 and machining, 2 to stabilized 3 and scanning interferometers. 4 The main advantage of using a retroreflector over a mirror is that it returns the light to its source without great sensitivity to alignment.…”

“…5 While there are many retroreflector designs, hollow retroreflectors serve an important role in Fourier transform spectroscopy, 6 laser stabilization, 7 and interference-based ultrafast techniques. 3,4 Hollow retroreflectors are preferred over other designs because they have lower masses than solid retroreflectors. They also minimize the chromatic dispersion that lengthens ultrafast pulses.…”

“…8 These phase shifts can be eliminated by mounting retroreflectors on piezoelectric transducers. 3 Hollow rooftop mirrors (HRMs) allow beams to be stacked without inversion of the stack and can preserve polarization (unlike trihedral retroreflectors). For a 90 deg angle between plane mirror surfaces, HRMs retroreflect light incident in planes perpendicular to the mirror joint axis (dihedral retroreflection).…”