Phase Nanoscopy with Correlated Frequency Combs.

This study addresses any sensor based on measuring a physical quantity through the phase of a probing beam. This includes sensing of rotation, acceleration, index change, displacement, fields… While most phase measurements are made by detecting an amplitude change in interfering beams, we detect instead a phase change through a relative frequency shift of two correlated frequency combs. This paper explores the limit sensitivity that this method can achieve, when the combs are generated in an Optical Parametric Oscillator (OPO), pumped synchronously by a train of femtosecond pulses separated by half the OPO cavity round-trip time.

High-resolution remote spectroscopy and plasma dynamics induced with UV filaments.

Spectroscopy is performed on the plume created by a high-power short-pulse laser on a solid surface. It is shown that high resolution (<10  pm) and accurate spectral analysis can be performed using a self-absorption feature appearing within the emission lines. The time-dependent self-absorption study reveals dynamics of a shock wave.

A Sagnac Fourier spectrometer.

A spectrometer based on a Sagnac interferometer, where one of the mirrors is replaced by a transmission grating, is introduced. Since the action of a transmission grating is reversible, both directions experience the same diffraction at a given wavelength. At the output, the crossed wavefronts are imaged onto a camera, where their Fizeau fringe pattern is recorded.

Impact of resonant dispersion on the sensitivity of intracavity phase interferometry and laser gyros.

Intracavity phase interferometry is a phase sensing technique using mode-locked lasers in which two intracavity pulses circulate. The beat frequency between the two output frequency combs is proportional to a phase shift to be measured. A laser gyro is a particular implementation of this device.

Concerning the Spatial Heterodyne Spectrometer.

A modified Spatial Heterodyne Spectrometer (SHS) is used for measuring atomic emission spectra with high resolution. This device is basically a Fourier Transform Spectrometer, but the Fourier transform is taken in the directions perpendicular to the optical propagation and heterodyned around one preset wavelength. In recent descriptions of this device, one specific phenomenon - the tilt of the energy front of wave packets when diffracted from a grating - was neglected.