Public access from Jun 1, 2020
Université de Neuchâtel

10 kHz linewidth mid-infrared quantum cascade laser by stabilization to an optical delay line

Shehzad, Atif ; Brochard, Pierre ; Matthey, Renaud ; Südmeyer, Thomas ; Schilt, Stéphane

In: Optics Letters, 2019, vol. 44, no. 4, p. 3470-3473

We present a mid-infrared quantum cascade laser (QCL) with a sub-10 kHz full width at half-maximum linewidth (at 1 s integration time) achieved by stabilization to a free-space optical delay line. The linear range in the center of a fringe detected at the output of an imbalanced Mach–Zehnder interferometer implemented with a short free-space pathlength difference of only 1 m is used as a...

Université de Neuchâtel

Electrically-driven pure amplitude and frequency modulation in a quantum cascade laser

Shehzad, Atif ; Brochard, Pierre ; Matthey, Renaud ; Blaser, Stéphane ; Gresch, Tobias ; Maulini, Richard ; Muller, Antoine ; Südmeyer, Thomas ; Schilt, Stéphane

In: Optics Express, 2018, vol. 26, no. 9, p. 12306-12317

We present pure amplitude modulation (AM) and frequency modulation (FM) achieved electrically in a quantum cascade laser (QCL) equipped with an integrated resistive heater (IH). The QCL output power scales linearly with the current applied to the active region (AR), but decreases with the IH current, while the emission frequency decreases with both currents. Hence, a simultaneous modulation...

Université de Neuchâtel

All‑fiber versatile laser frequency reference at 2 μm for CO2 space‑borne lidar applications

Schilt, Stéphane ; Matthey, Renaud ; Hey Tow, Kenny ; Thévenaz, Luc ; Südmeyer, Thomas

In: CEAS Space Journal, 2017, vol. 9, no. 4, p. 493-505

We present a frequency stabilized laser at 2051 nm based on a versatile all-fibered stabilization setup. A modulation sideband locking technique is implemented to lock the laser at a controlled frequency detuning from the center of the CO2 R(30) transition envisaged for space-borne differential absorption lidar (DIAL) applications. This method relies on the use of a compact all-fibered...

Université de Neuchâtel

Interferometric measurements beyond the coherence length of the laser source

Salvadé, Yves ; Przygodda, Frank ; Rohner, Marcel ; Polster, Albert ; Meyer, Yves ; Monnerat, Serge ; Gloriod, Olivier ; Llera, Miguel ; Matthey, Renaud ; Di Francesco, Joab ; Gruet, Florian ; Mileti, Gaetano

In: Optics Express, 2016, vol. 24, no. 19, p. 21729-21743

Interferometric measurements beyond the coherence length of the laser are investigated theoretically and experimentally in this paper. Thanks to a high-bandwidth detection, high-speed digitizers and a fast digital signal processing, we have demonstrated that the limit of the coherence length can be overcome. Theoretically, the maximal measurable displacement is infinite provided that the sampling...

Université de Neuchâtel

Rb-stabilized laser at 1572 nm for CO2 monitoring

Matthey, Renaud ; Moreno, William ; Gruet, Florian ; Brochard, Pierre ; Schilt, Stéphane ; Mileti, Gaetano

In: Journal of Physics: Conference Series, 2016, vol. 723, no. 1, p. 012034

We have developed a compact rubidium-stabilized laser system to serve as optical frequency reference in the 1.55-μm wavelength region, in particular for CO2 monitoring at 1572 nm. The light of a fiber-pigtailed distributed feedback (DFB) laser emitting at 1560 nm is frequency-doubled and locked to a sub-Doppler rubidium transition at 780 nm using a 2-cm long vapor glass cell. Part of...

Université de Neuchâtel

Compact rubidium-stabilized multi-frequency reference source in the 1.55-μm region

Matthey, Renaud ; Gruet, Florian ; Schilt, Stéphane ; Mileti, Gaetano

In: Optics Letters, 2015, vol. 40, no. 11, p. 2576-2579

Combining light modulation and frequency conversion techniques, a compact and simple frequency-stabilized optical frequency comb spanning over 45 nm in the 1.56- μm wavelength region is demonstrated. It benefits from the high-frequency stability achievable from rubidium atomic transitions at 780 nm probed in a saturation absorption scheme, which is transferred to the 1.56- μm spectral region...

Université de Neuchâtel

Methods and evaluation of frequency aging in distributed-feedback laser diodes for rubidium atomic clocks

Matthey, Renaud ; Affolderbach, Christoph ; Mileti, Gaetano

In: Optics Letters, 2011, vol. 36, no. 17, p. 3311-3313

Distributed-feedback laser diodes emitting at 780 nm have been evaluated, with respect to the aging of the injection current required for reaching the rubidium D2 resonance line. Results obtained for lasers operating in air and in vacuum for 9 months are reported. When operated at constant temperature, the laser current required for emission at the wavelength of the desired atomic resonance is...

Université de Neuchâtel

Comparison between Backscatter Lidar and Radiosonde Measurements of the Diurnal and Nocturnal Stratification in the Lower Troposphere

Martucci, Giovanni ; Matthey, Renaud ; Mitev, Valentin ; Richner, Hans

In: Journal of Atmospheric and Oceanic Technology, 2007, vol. 24, no. 7, p. 1231-1244

A collection of boundary layer heights has been derived from measurements performed by a ground-based backscatter lidar in Neuchâtel, Switzerland (47.000°N, 6.967°E, 485 m ASL). A dataset of 98 cases have been collected during 2 yr. From these data, 61 are noon and 37 are midnight cases. The following two different schemes were used to retrieve the mixed layer depth and the height of the...

Université de Neuchâtel

Diode laser frequency stabilisation for water-vapour differential absorption sensing

Matthey, Renaud ; Schilt, Stéphane ; Werner, D. ; Affolderbach, Christoph ; Thévenaz, Luc ; Mileti, Gaetano

In: Applied Physics B : Lasers and Optics, 2006, vol. 85, no. 2-3, p. 477-485

We describe a low-power continuous-wave laser system for water-vapour sensing applications in the 935-nm region. The system is based on extended-cavity diode lasers and distributed-feedback lasers and delivers four single-mode frequency-stabilised optical signals. Three lasers are locked to three water-vapour absorption lines of different strengths, whereas the fourth lies outside any absorption...

Université de Neuchâtel

Frequency of Boundary-Layer-Top Fluctuations in Convective and Stable Conditions Using Laser Remote Sensing

Martucci, Giovanni ; Matthey, Renaud ; Mitev, Valentin ; Richner, Hans

In: Boundary-Layer Meteorology, 2010, vol. 135, no. 2, p. 313-331

The planetary boundary-layer (PBL) height is determined with high temporal and altitude resolution from lidar backscatter profiles. Then, the frequencies of daytime thermal updrafts and downdrafts and of nighttime gravity waves are obtained applying a fast Fourier transform on the temporal fluctuation of the PBL height. The principal frequency components of each spectrum are related to the...