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

Single-Frequency High-Power Continuous-Wave Oscillation at 1003 nm of an Optically Pumped Semiconductor Laser

This work reports single-frequency laser oscillation at 1003.4 nm of an optically pumped external cavity semiconductor laser. By using a gain structure bonded onto a high conductivity substrate, we demonstrate both theoretically and experimentally the strong reduction of the thermal resistance of the active semiconductor medium, resulting in a high power laser emission. The spectro-temporal dynamics of the laser is also explained. Furthermore, an intracavity frequency-doubling crystal was used to obtain a stable single-mode generation of blue (501.5 nm) with an output power around 60 mW.Comment: 11 page

Single-frequency diode-pumped semiconductor laser tuned on a Cs transition

Diode-pumped semiconductor lasers have already demonstrated high powers in circular diffraction-limited output beams and single-frequency laser emission. Our work is focused on the design of a laser structure suitable for Cesium (Cs) atomic clock experiments that could merge both properties

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