1,721,018 research outputs found
Mid-infrared optical combs from a compact amplified Er-doped fiber oscillator
No full textBy means of a difference-frequency-generation (DFG) process driven by a two-branch Er-doped fiber laser at
a stabilized 100 MHz repetition rate, broadly tunable pulses from 5 to 12 um are generated with an unprecedented
power level of around 100 uW. The mid-IR pulse train is expected to exhibit an harmonic comb
structure as a result of the cancellation of the carrier-envelope offset frequency resulting from the DFG
process
Scanning micro-resonator direct-comb absolute spectroscopy
Full text linkDirect optical Frequency Comb Spectroscopy (DFCS) is proving to be a fundamental tool in many areas of science and technology thanks to its unique performance in terms of ultra-broadband, high-speed detection and frequency accuracy, allowing for high-fidelity mapping of atomic and molecular energy structure. Here we present a novel DFCS approach based on a scanning Fabry-Pérot micro-cavity resonator (SMART) providing a simple, compact and accurate method to resolve the mode structure of an optical frequency comb. The SMART approach, while drastically reducing system complexity, allows for a straightforward absolute calibration of the optical-frequency axis with an ultimate resolution limited by the micro-resonator resonance linewidth and can be used in any spectral region from UV to THz. We present an application to high-precision spectroscopy of acetylene at 1.54 μm, demonstrating performances comparable or even better than current state-of-the-art DFCS systems in terms of sensitivity, optical bandwidth and frequency-resolution
Tunable frequency combs in the fingerprint region from a compact erbium-doped fiber oscillator
No full textTunable frequency combs in the fingerprint region from a compact erbium-doped fiber oscillato
Frequency-noise measurements of optical frequency combs by multiple fringe-side discriminator
Full text linkThe frequency noise of an optical frequency comb is routinely measured through the hetherodyne beat of one comb tooth against a stable continuous-wave laser. After frequency-to-voltage conversion, the beatnote is sent to a spectrum analyzer to retrive the power spectral density of the frequency noise. Because narrow-linewidth continuous-wave lasers are available only at certain wavelengths, heterodyning the comb tooth can be challenging. We present a new technique for direct characterization of the frequency noise of an optical frequency comb, requiring no supplementary reference lasers and easily applicable in all spectral regions from the terahertz to the ultraviolet. The technique is based on the combination of a low finesse Fabry-Perot resonator and the so-called "fringe-side locking" method, usually adopted to characterize the spectral purity of single-frequency lasers, here generalized to optical frequency combs. The effectiveness of this technique is demonstrated with an Er-fiber comb source across the wavelength range from 1 to 2 μm
High-power frequency comb in the range of 2–2.15 μm based on a holmium fiber amplifier seeded by wavelength-shifted Raman solitons from an erbium-fiber laser
No full textWe demonstrate a room-temperature high-power frequency comb source covering the spectral region from 2 to 2.15 μm. The source is based on a femtosecond erbium-fiber laser operating at 1.55 μm with a repetition rate of 250 MHz, wavelength-shifted up to 2.06 μm by the solitonic Raman effect, seeding a large-mode-area holmium (Ho) fiber amplifier pumped by a thulium (Tm) fiber laser emitting at 1.94 μm. The frequency comb has an integrated power of 2 W, with overall power fluctuations as low as 0.3%. The beatnote between the comb and a high-spectral-purity, single-frequency Tm–Ho laser has a linewidth of 32 kHz over 1 ms observation time, with a signal-to-noise ratio in excess of 30 dB
Kinetics of interfacial charges in hybrid GaAs/oligothiophene semiconducting heterojunctions
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