Long-wave infrared multi-wavelength optical source for standoff detection of chemical warfare agents.

We have designed and built a wavelength-tunable optical source for standoff detection of gaseous chemicals by differential absorption spectrometry in the long-wave infrared. It is based on a nanosecond 2 µm single-frequency optical parametric oscillator, whose idler wave is amplified in large aperture Rb:PPKTP crystals. The signal and idler waves are mixed in crystals to produce single-frequency tunable radiation in the 7.

Atmospheric boundary layer CO remote sensing with a direct detection LIDAR instrument based on a widely tunable optical parametric source.

We report on the capability of a direct detection differential absorption lidar (DIAL) for range resolved and integrated path (IPDIAL) remote sensing of CO in the atmospheric boundary layer (ABL). The laser source is an amplified nested cavity optical parametric oscillator (NesCOPO) emitting approximately 8 mJ at the two measurement wavelengths selected near 2050 nm. Direct detection atmospheric measurements are taken from the ground using a 30 Hz frequency switching between emitted wavelengths.

Wide and fast dispersion tuning of a picosecond OPO based on aperiodic quasi-phase matching using an axially chirped volume Bragg grating.

We report on a widely tunable synchronously pumped picosecond optical parametric oscillator (OPO) combining an aperiodically poled MgO-doped LiNbO crystal as a broadband gain medium and an axially chirped volume Bragg grating as a spectral filtering dispersive element. Translation of the Bragg grating along the beam axis enables wavelength tuning over 215 nm around 3.82 μm and provides spectral narrowing.

Active stabilization of a rapidly chirped laser by an optoelectronic digital servo-loop control.

We propose and demonstrate a novel active stabilization scheme for wide and fast frequency chirps. The system measures the laser instantaneous frequency deviation from a perfectly linear chirp, thanks to a digital phase detection process, and provides an error signal that is used to servo-loop control the chirped laser. This way, the frequency errors affecting a laser scan over 10 GHz on the millisecond timescale are drastically reduced below 100 kHz.

Wideband and high-resolution coherent optical transients with a frequency-agile laser oscillator.

We report what is believed to be the first experimental demonstration of a wideband spectral coherent process driven by a frequency-agile laser in a rare-earth-ion-doped crystal. The very demanding chirp-transform algorithm is studied in detail and is applied to radio-frequency spectral analysis. A time-bandwidth product of 24,000 is demonstrated.