Tunable Single-frequency operation of a diode-pumped Vertical-External Cavity Laser at the Caesium D2 line

International audienceWe report on a diode-pumped vertical external-cavity surface-emitting laser emitting around 852 nm for Cesium atomic clocks experiments. We have designed a 7-quantum-well semiconductor structure optimized for low laser threshold. An output power of 330 mW was achieved for 1.1 W of incident pump power. Furthermore a compact setup was built for low-power single-requency emission. We obtained an output power of 17 mW in a single longitudinal mode, exhibiting both broad (9 nm) and continuous (14 GHz) tunability around the Cesium D2 line. The laser frequency has been stabilized on an atomic transition with residual frequency fluctuations ~ 300 kHz. Through a beatnote experiment the -3 dB laser linewidth has been measured to < 500 kHz over 10 ms

COMPACT AND ROBUST SINGLE-FREQUENCY DIODE-PUMPED VECSEL AT THE CESIUM D2 LINE FOR ATOMIC CLOCKS

This work reports on an optically-pumped vertical external-cavity surface­emitting laser emitting around 852 nm dedicated to atomic physics experiments with cold Cs atoms. The design of the semiconductor active structure has been optimized to provide a low threshold. A low-power diode-pumped compact prototype has been developed with improved stability. With this setup, we obtained a 17-mW single frequency emission exhibiting large tunability around the Cesium D2 line. The laser linewidth has been measured to less than 500 kHz on a 10 ms time

Multipolar Photoconductive Antennas for THz Emission Driven by a Dual-Frequency Laser Based on Transverse Modes

Continuous-wave tunable photonics-based THz sources present limited output power due to the restricted input optical power accepted by photomixers, along with reduced radiation resulting from low paraxial field amplitude. Here, we investigate multipolar antenna designs to increase the available continuous-wave THz output power by incorporating more photomixers. For this purpose, the spatial structures of the optical and THz E-fields are designed to enhance THz power and radiation in the far field. Simulations of 2 to 4 dipole antennas are conducted, demonstrating an improvement in antenna gain compared to standard dipole antennas. This is in addition to a potential increase in THz power and radiation for photomixing applications. Such work also paves the way for functionalizing the spatial structure of THz light for advanced applications

Optical-Feedback Cavity-Enhanced Absorption Spectroscopy Using a Short-Cavity Vertical-External-Cavity Surface-Emitting Laser

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HIGH SENSITIVITY INTRA-CAVITY LASER ABSORPTION SPECTROSCOPY WITH VERTICAL EXTERNAL CAVITY SURFACE EMITTING SEMICONDUCTOR LASERS

Author Institution: Laboratoire de Spectrom\'{e}trie Physique; Laboratoire de Microstructures et de Micro\'{e}lectronique; Institut de Microet Opto\'{e}lectronique - EPFL, CH 1015, Lausanne. Switzerland., Laboratoire de Microstructures et de Micro\'{e}lectroniqueWe report the demonstration of high sensitivity Intra-Cavity-Laser-Absorption-Spectroscopy (ICLAS) employing Multiple-Quantum-Well Vertical-External-Cavity Surface-Emitting semiconductor Lasers (VECSEL's). A detection limit of $10^{-10} cm^{-1}$ has been achieved. The spectro-temporal dynamics of a broadband VECSEL in the 1000 nm wavelength range has been studied in order to determine the sensitivity limit of the new class of the laser materials suitable for ICLAS. The laser was operating CW at room-temperature, with a baseline signal to noise ratio as high as 400. The laser was diode pumped with a threshold as low as 110 mW and broadly tunable over a spectral range of about 76 nm. In the nearest future this should allow developing very compact transportable ICLAS instruments, suitable for in situ measurements. VECSEL systems offer very wide operating range in the near- and mid-Infrared from $0.7 \mu$m to $2.5 \mu$m

Self-mixing in low-noise semiconductor vortex laser: detection of a rotational Doppler shift in backscattered light

International audienceLight carrying orbital angular momentum (L) over right arrow, scattered by a rotating object at angular velocity (Omega) over right arrow, experiences a rotational Doppler shift (Omega) over right arrow.(L) over right arrow. We show that this fundamental light-matter interaction can be detected exploiting self-mixing in a vortex laser under Doppler-shifted optical feedback, with quantum noise-limited light detection. We used a low-noise relaxation oscillation-free (class-A) vortex laser, based on III-V semiconductor vertical-external-cavity-surface-emitting laser technology to generate coherent Laguerre-Gauss beams carrying L = hl (l = +/- 1,...+/- 4). Linear and rotational Doppler effects were studied experimentally and theoretically. This will allow us to combine a velocity sensor with optical tweezers for micro-manipulation applications, with high performances: compact, powerful >> 10 mW, high-quality beam, auto-aligned, linear response up to > 10(8) rad/s or > 300 km/h, low back-scattered light detection limit < 10(-16)/Hz

Structured light from Photonic & THz coherent sources based on III-V semiconductor laser technology

3D Structured coherent electromagnetic field emitting in the optical and/or THz spectral domain is a hot topic and of great interest for a large panel of applications in opto-hyper field, both in the fondamental and applied domains: telecom, LIDAR, sensing, optical tweezers, biophotonics, spectroscopy... We will present an overview of our recent results on 3D (time-space) structured coherent electromagnetic field [1,2,4], emitting in the near-IR and THz spectral domain. These photnic devices are based on III-V semiconductor VECSEL laser technology [3], and exploiting parity symmetry-breaking together with metasurafce and photo-conductive antenna nanotechnology. We demonstrated a vortex laser with controlled orbital angular momentum allowing both linearrotationnal doppler based speed sensing under light matter-interaction [1], spatially modeless laser and light multiplexing [4], non-linear structured light [4,5], dual-mode laser based tunable coherent THz emitter [2]... We will discuss the ongoing work towards light bullets photonic device, multiplex structured coherent photonic sources and plasmonics photomixer based powerfull cw THz emitter, of great interest for challenging applications

GaSb-based VCSELs emitting in the mid-infrared wavelength range (2-3 µm) grown by MBE

International Conference on Molecular Beam Epitaxy (MBE-XV), The 15th International Conference on Molecular Beam Epitaxy (MBE-XV)International audienceWe report the growth conditions and operations of electrically pumped monolithic Sb-based type-I quantum-well vertical cavity surface emitting lasers (VCSELs) emitting above 2.2 µm. The structures were grown on (001)-GaSb substrates by molecular beam epitaxy(MBE)and are made of two N-type GaSb/AlAsSb Bragg reflectors,a GaInAsSb/AlGaAsSb multiquantum-well active region and an InAsSb/GaSb tunnel junction. Growth conditions have been optimized for each target wavelength. Laser emission in CW up to 293K at 2.3 µm and in pulsed regime at 2.52 µm at room temperature(RT)is demonstrated. These are the longest wavelength achieved with electrically pumped VCSELs to date