ABSTRACT
We demonstrate carrier-envelope phase stabilization of a mode-locked Ti:sapphire laser by use of quantum interference control of injected photocurrents in a semiconductor. No harmonic generation is required for this stabilization technique. Instead, interference between coexisting single- and two-photon absorption pathways in the semiconductor provides a phase comparison between different spectral components. The phase comparison, and the detection of the photocurrent that it produces, both occur within a single low-temperature-grown gallium arsenide sample. The carrier-envelope offset beat note fidelity is 30 dB in a 10-kHz resolution bandwidth. The out-of-loop phase-noise level is essentially identical to the best previous measurements with the standard self-referencing technique.
ABSTRACT
We demonstrate quantum interference control of injected photocurrents in a semiconductor using the phase stabilized pulse train from a mode-locked Ti:sapphire laser. Measurement of the comb offset frequency via this technique results in a signal-to-noise ratio of 40 dB (10 Hz resolution bandwidth), enabling solid-state detection of carrier-envelope phase shifts of a Ti:sapphire oscillator.
ABSTRACT
We demonstrate a diode-pumped cw Raman laser in H(2) with photon-conversion efficiency of (66+/-8)%. Pumped by an injection-locked diode laser at 792 nm, the Stokes laser produces a peak output power of ~16mW at 1180 nm. Accompanying the high Stokes power are deviations from the existing theory, which are believed to be caused by the thermal-lensing effect of the Raman gas.
ABSTRACT
What is to the authors' knowledge the first experimental demonstration of a nonresonant cw Raman laser pumped by a tunable external-cavity diode laser (ECDL) is presented. The ECDL is phase-frequency locked to a high-finesse Raman laser cavity containing diatomic hydrogen (H(2)) by the Pound-Drever-Hall locking technique. The Stokes lasing threshold occurs at a pump power of 400 +/- 30 muW, and a maximum photon conversion efficiency of 12.0 +/- 1.3% is achieved at 1.6 mW of pump power. A 40-nm tuning range of the cw Stokes emission, 1174-1214 nm, is obtained by tuning of the wavelength of the ECDL pump source.
ABSTRACT
We demonstrate a nonresonant cw Raman laser pumped by an optically locked diode laser at 790 nm that produces cw Stokes (1178-nm) and coherent anti-Stokes (595-nm) emission. Considering the modest pump powers, relative low cost, and predicted spectral purity, we expect that frequency downconversion of tunable diode lasers through stimulated Raman scattering will provide an attractive source for remote sensing, spectroscopic, and atomic physics applications. The Stokes laser threshold is 240+/-19muW pump power, and emission is observed over a roughly 10-nm range by adjustment of the optical locking feedback phase. Photon-conversion efficiency rises throughout the pump-power region, with a peak value of 15+/-2% .
ABSTRACT
We describe a sensitive and inexpensive vibrometer based on optical feedback by diffuse scattering to a single-mode diode laser. Fluctuations in the diode laser's operating frequency that are due to scattered light from a vibrating surface are used to detect the amplitude and frequency of surface vibrations. An additional physical vibration of the laser provides an absolute amplitude calibration. The fundamental bandwidth is determined by the laser response time of roughly 10(-9)s. A noise floor of 0.23 nm/Hz(1/2) at 30 kHz with 5 × 10(-5) of the incident light returning is demonstrated. This instrument provides an inexpensive and sensitive method of noncontact measurement in solid materials with low or uneven reflectivity. It can be used as a vibration or velocity sensor.
