Widely tunable sum-frequency generation in PPLN waveguide pumped by a multi-wavelength Yb-doped fiber laser

We present some experimental results on tunable sum-frequency generation in a periodically poled lithium-niobate waveguide using a multi-wavelength fiber laser pump stabilized by a nonlinear optical loop mirror. We are able to up-convert to about 629 nm a continuous-wave infrared signal varying from 1497 nm to 1525 nm. Such a wideband conversion efficiency is ensured by the multiple spectral components of the laser pump, which is controlled by an adjustable Fabry-Perot filter. Potential applications, in particular for stellar imaging, are discussed.     

A broadly tunable IR waveguide Raman laser pumped by a dye laser

Design and performance characteristics of a tunable ir waveguide Raman laser pumped by a high power dye laser are described. Using SRS up to third Stokes order in compressed H₂, the wavelength range from 0.7 to 7 μm has been covered without gaps. Taking advantage of a waveguide structure in the scattering chamber, energy conversion efficiencies better than 1% with power levels in excess of 80 kW for the third Stokes component have been achieved. The experimental results support the theoretical predictions that a 4-wave parametric process is responsible for the production of the third Stokes component.     

Blue light generation in a ridge waveguide MgO:LiNbO3 crystal pumped by a fiber Bragg grating stabilized laser diode

We report cw blue light generation by using a periodically poled MgO:LiNbO(3) crystal with a ridge waveguide pumped by a fiber Bragg grating stabilized laser diode with 0.25 nm spectrum width in the coherent collapse regime. Blue light generation of 73 mW with 27% conversion efficiency and a wide temperature tolerance of 5.7 degrees C were attained.     

1.1-W cw Cr:LiSAF laser pumped by a 1-cm diode array

We demonstrate 1.1-W cw output power from a diode-laser array-pumped Cr:LiSAF laser based on a concept that allows for pumping low-gain solid-state lasers at reduced temperature rise. We discuss scaling to higher powers as a function of diode power and define a figure of merit for evaluating given diode lasers as pump sources for low-gain solid-state lasers.     

Stabilized diode laser pumped, idler-resonant cw optical parametric oscillator

We present a diode laser pumped continuous wave, pump-enhanced singly-resonant optical parametric oscillator (OPO). The cavity is stabilized by a Pound?CDrever?CHall scheme using direct modulation of the diode laser. The system provides stable signal powers of up to 220?mW. The wavelength can be tuned between 1.40?C1.60???m for a ring or a linear cavity design by changing the crystal temperature. The relative fluctuations of the stabilized OPO??s wavelength are less than 10^?7 for more than one hour. Using a self-heterodyne technique, we measure a linewidth of the signal wave of 3.5?MHz.     

Widely tunable continuous-wave Raman laser in diatomic hydrogen pumped by an external-cavity diode laser

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.     

Spectral narrowing of a flashlamp-pumped,waveguide dye laser by amplification of tunable narrow-band cw radiation

Spectral narrowing of the broad-band emission from a flashlamp-pumped dye laser, which consisted of a slab waveguide high-gain amplifier in conjunction with a high-loss resonator, is reported.The pulsed laser oscillator was driven by a cw dye laser oscillating in several longitudinal modes. An energy output up to 10 mJ per pulse has been obtained with a driving power of 10 mW, showing the possibility of substantial power amplification of the narrow-band emission from a cw dye laser.     

Broadband tunable external cavity laser using a bent-waveguide quantum-dot superluminescent diode as gain device

A broadband tunable grating-coupled external cavity laser is realized by employing a self-assembled InAs/GaAs quantum-dot (QD) superluminescent diode (SLD) as the gain device. The SLD device is processed with a bent-waveguide structure and facet antireflection (AR) coating. Tuning bandwidths of 106 nm and 117 nm are achieved under 3-A and 3.5-A injection currents, respectively. The large tuning range originates essentially from the broad gain spectrum of self-assembled QDs. The bent waveguide structure combined with the facet AR coating plays a role in suppressing the inner-cavity lasing under a large injection current.     

Characteristics of a continuous-wave Yb:GdVO4 laser end pumped by a high-power diode

An efficient and compact diode-pumped continuous-wave Yb:GdVO4 laser is demonstrated, generating an output power of 4.0 W with an optical conversion efficiency of 61% and a slope efficiency as high as 78%. With increasing pump power the polarization of the laser output changes from sigma to pi, while in a certain intermediate power range the two polarization states coexist with different emission wavelengths.     

Second harmonic generation by femtosecond Yb-doped fiber laser source based on PPKTP waveguide fabricated by femtosecond laser direct writing

The frequency doubling of femtosecond pulses from an Yb-doped fiber laser source was demonstrated in a PPKTP waveguide fabricated by femtosecond laser direct writing. The PPKTP waveguide contains a fixed period of 8.9 μm and the feomtosecond fundamental pulses have a central wavelength of 1044 nm. A maximum SHG power of 406 mW was produced, yielding a conversion efficiency of 5.6%. Numerical simulations were carried out to investigate the property of frequency doubling for femtosecond pulses. The results show that the SHG process proceeds even the quasi-phase-matching (QPM) condition is not well satisfied, which is significantly different from that of “long” pulses or CW light and is accorded with the experimental results.     

Free-running emerald laser pumped by laser diode

Free-running emerald laser pumped by 660-nm laser diode (LD) was reported. Free-running output powerof 24 mW has been obtained with overall efficiency of 1.4% and slope efficiency of 11.9% when the LD incident power was 2.56 W. The laser threshold value of emerald crystal was estimated to be 0.7 W.     

Dispersion in a cw optically pumped FIR laser

Direct frequency measurements of a¹³CO₂/¹⁵NH₃ OPFIRL output show that laser pulling effects give shifts of a few MHz, which agree well with a density matrix calculation.     

Supercontinuum generation in quasi-phase-matched LiNbO3 waveguide pumped by a Tm-doped fiber laser system

We demonstrate self-referencing of a Tm-doped fiber oscillator-amplifier system by performing octave-spanning supercontinuum generation in a periodically poled lithium niobate waveguide. We model the supercontinuum generation numerically and show good agreement with the experiment.     

The generation of tunable near IR radiation using a nitrogen laser pumped dye laser

Excitation transfer between the two components of a dye mixture has allowed a near IR dye laser to be pumped by a nitrogen laser. Several dye mixtures were employed to achieve lasing at all wavelengths within the range 6400–7720 Å. The output pulse powers were in excess of 10 kW over most of this range.     

Transform-limited behavior from the synchronously pumped cw dye laser

We report for the first time transform limited behavior from the picosecond synchronously pumped cw dye laser. This is accomplished by the use of an inexpensive, low-loss intra-cavity etalon. The Fourier relationship between pulse frequency width and time duration is shown to be obeyed quantitatively at three different wavelengths. The pulse profile changes as a function of wavelength and does not follow an analytical functionality at any wavelength studied. For each wavelength, the optical cavity length producing transform limited pulses is shown to be the same.     

High-average-power Nd:YAG planar waveguide laser that is face pumped by 10 laser diode bars

A planar waveguide Nd:YAG laser is pumped with 430 W of power from 10 laser diode bars to produce a multimode output power of 150 W at an optical efficiency of 35%. Use of a hybrid resonator of the positive-branch confocal unstable type for the lateral axis and of one of the near-case I waveguide type for the transverse axis increased the laser brightness by a factor of ~26 with only 12% less power than in the multimode case.     

New FIR laser lines from CHD2OH optically pumped by a cw CO2 laser

This work reports 83 new optically pumped far infrared laser lines, using deuterated methyl alcohol, CHD₂OH, as active medium. For each line we list the measured wavelength, its polarization relative to the pump line, the optimum gas pressure and the CO₂ laser pump power at the maximum absorption.     

Travelling-wave operation of a tunable cw dye laser

A ring cavity configuration for a tunable cw dye laser is described. A substantial reduction of the output bandwidth of the ring laser with increase in power for unidirectional or traveling-wave operation has been demonstrated. The advantages of the ring configuration for single-frequency operation of cw dye lasers are explored.     

Single mode operation of a tunable cw dye laser

Using the differential absorption method the NO₂ concentration within the plume of a smoke stack and over the area of a chemical factory was measured.     

New cw FIR laser lines from optically pumped ammonia analogues

Two new cw submillimetre lines optically pumped by the 9 μR(30) CO₂ laser have been observed for¹⁴NH₃ and assigned to thea(6,0)→s(5,0) transition and to its cascade transitions(5,0)→a(4,0) in thev ₂=1 state. In addition, six new emission lines have been observed for NH₂D, and one tentatively assigned to the (11,1)→(10,1) transition of ND₃. Methylamine has also been investigated and twenty-eight new emission lines have been discovered.